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*** START OF THE PROJECT GUTENBERG EBOOK 78213 ***




[Illustration]




                             SHRAPNEL SHELL
                              MANUFACTURE

                A COMPREHENSIVE TREATISE ON THE FORGING,
                MACHINING, AND HEAT-TREATMENT OF SHELLS,
                 AND THE MANUFACTURE OF CARTRIDGE CASES
                  AND FUSES FOR SHRAPNEL USED IN FIELD
                AND MOUNTAIN ARTILLERY, GIVING COMPLETE
                DIRECTION FOR TOOL EQUIPMENT AND METHODS
                 OF SETTING UP MACHINES, TOGETHER WITH
                GOVERNMENT SPECIFICATIONS FOR THIS CLASS
                              OF MUNITIONS

                         By DOUGLAS T. HAMILTON

                      ASSOCIATE EDITOR OF MACHINERY
                 AUTHOR OF “ADVANCED GRINDING PRACTICE,”
                   “AUTOMATIC SCREW MACHINE PRACTICE,”
                         “MACHINE FORGING,” ETC.

                             _FIRST EDITION_


                                NEW YORK
                          THE INDUSTRIAL PRESS
                                  1915




                             COPYRIGHT, 1915
                                   BY
                          THE INDUSTRIAL PRESS
                                NEW YORK




PREFACE


The design of shrapnel and the machining of its component parts
are matters which, at the present time, are of world-wide interest
to manufacturers, engineers, toolmakers, and mechanics in general.
Shrapnel is used in enormous quantities in the great European war,
and American machine tool builders have been called upon to provide
machines and tool equipment of the latest and most efficient design to
meet the demands made upon the manufacturers of shrapnel. Many shops
are running full force, day and night, and are months behind with their
orders. The great importance of shrapnel manufacture, at the present
time, is, therefore, unquestioned.

A small percentage of shrapnel shells are now made from bar stock, but
most shrapnel bodies are made from forgings, formed hollow in hydraulic
presses or in forging machines. The forging processes, which are of
extraordinary interest, especially to those who know something of the
difficulties attending them, are, however, not finishing processes.
Whether made from the bar or forged hollow, all shrapnel shells must be
very accurately finished by machining.

This book has been brought out to meet the demands for a treatise
dealing comprehensively with the construction, forging and machining
operations, and the tool equipment used for making the shell, fuse
parts, and brass cases. In this book are included not only the
unusually complete articles on shrapnel manufacture contained in the
April, 1915, number of MACHINERY, of which 5000 extra copies were
printed and 5000 additional reprints made, all of which have been sold,
but it also includes all other material that has been published at
various times in MACHINERY relating to shrapnel manufacture, together
with a great deal of material obtained by the Editors especially for
this book; and, in addition to this, it contains abstracts of the
official specifications, together with line-engravings of the details
of Russian, British, and American shrapnel shell bodies, fuses, and
cartridge cases. Hence, it is believed that the book will prove
the most valuable addition to the literature on the manufacture of
munitions that has been made since the beginning of the great war.

                                                            D. T. H.

NEW YORK, _October, 1915_.




CONTENTS


  CHAPTER I.

  Shrapnel Shells                                                   1-19

  CHAPTER II.

  Forging Shrapnel Shells                                          20-39

  CHAPTER III.

  Machining and Heat-treatment of Shrapnel Shells                  40-74

  CHAPTER IV.

  Machines and Tools for Shrapnel Manufacture                     75-142

  CHAPTER V.

  Making Fuse Parts                                              143-171

  CHAPTER VI.

  Making Shrapnel Cartridge Cases                                172-193

  CHAPTER VII.

  Specifications for the Manufacture and Inspection of the
  Russian 3-inch Shrapnel Shell                                  194-212

  CHAPTER VIII.

  Specifications for the Manufacture and Inspection of the
  Combination Fuse for Russian 3-inch Shrapnel Shells            213-230

  CHAPTER IX.

  Specifications for the Manufacture and Inspection of
  Russian 3-inch Shrapnel and High-explosive Cartridge Cases     231-250

  CHAPTER X.

  Specifications for British 18-pounder Quick-firing
  Shrapnel Shell                                                 251-259

  CHAPTER XI.

  Specifications for British Combination Time and Percussion
  Fuses                                                          260-275

  CHAPTER XII.

  Specifications for British 18-pounder Quick-firing
  Cartridge Case and Primer                                      276-285

  CHAPTER XIII.

  Specifications for American Shrapnel Shells                    286-292

  INDEX                                                          293-296




CHAPTER I

SHRAPNEL SHELLS


In naval, coast defense and artillery operations, several types of
explosive shells are used; the chief ones are: the armor-piercing
shell, made to pierce armor-plate before exploding; shells exploded
by means of a timing fuse; shells exploded by either a timing or
percussion fuse; and shells exploded by percussion only. Each different
shell has some definite function to fulfill, and is designed for
that purpose. For field or artillery operations, the shrapnel and
lyddite are the two principal types used. Of these, shrapnel is the
most prominent, because of its destructive power and its interesting
mechanical construction.


=Early Development of Shrapnel.=--The shrapnel shell was invented
in 1784 by Lieut. Henry Shrapnel, and was adopted by the British
Government in 1808. As is shown at _A_ in Fig. 2, the first shell was
spherical in shape, and the powder or explosive charge was mixed with
the bullets. Although this type of shell was an improvement over the
grape and canister previously used, its action was not altogether
satisfactory, as the shell, on bursting, projected the bullets in all
directions and there was also a liability of premature explosion. In
order to overcome the defects mentioned, Col. Boxer separated the
bullets from the bursting charge by a sheet-iron diaphragm, as shown at
_B_ in Fig. 2. This shell was called a diaphragm shell to differentiate
it from the first shell of this type.

In the shell made by Col. Boxer, the lead bullets were hardened by the
addition of antimony, and as the bursting charge was small, the shell
was weakened by cutting four grooves extending from the fuse hole to
the opposite side of the shell. Shells of spherical shape were first
fired out of plain-bored guns, and upon the advent of the rifled gun
it was necessary to add a circular base, which was made of wood and
covered with sheet iron or steel to take the rifling grooves. The first
shrapnel shells were made of cast iron, but a later development was to
use steel and elongate the body, reducing it in diameter. The diameter
of the bullets was also reduced so that a greater number could be
contained in a slightly smaller space. The improved shrapnel was also
capable of being more accurately directed.


=Shrapnel Shells of Present-day Design.=--Shrapnel shells, as used
at the present time by the different governments, vary slightly in
construction and general contour as well as in the constituents
entering into their different members. As shown in Fig. 1, a completed
shrapnel comprises a brass case carrying a detonating primer and the
explosive charge for propelling the projectile out of the bore of
the gun. The projectile itself comprises a forged shell that carries
the lead bullets and bursting charge. Screwed into the front end is
the combination timing and percussion fuse which can be set so as to
explode the shell at any desired point, and from which the flame for
exploding the bursting charge is conveyed through a powder timing train
and a tube filled with powder pellets down through the diaphragm to the
powder pocket.

Of these members of a shrapnel, the shell and timing fuse present the
most interesting features from a mechanical standpoint. The shell used
by most governments is made from a forging, machined to the desired
dimensions in hand and semi-automatic turret lathes as well as in
ordinary engine lathes. The fuse is an extremely accurate piece of
mechanism, and is largely produced from screw machine parts, some of
which, however, are forged previous to machining. The brass cartridge
case--the next member of importance--is drawn from a brass blank by
successive operations in drawing presses, and is indented and headed.
Following this, several machining operations are performed on the head
and primer pocket.

[Illustration: Fig. 1. Types of Shrapnel Shells used by the American,
Russian, German, French, and British Governments]


=Types of Shrapnel Shells.=--Shrapnel shells are made in two distinct
types, one of which is known as the common shell, and the other as
the high-explosive. The common shell is a base-charged shrapnel,
fitted with a combination fuse, whereas the high-explosive shell is
fitted with a combination fuse and, in addition, with a high-explosive
head, the head also bursting and flying into atoms upon impact. The
high-explosive shell is not ruptured upon the explosion of the bursting
charge in the base, but the head is forced out and the bullets are
shot out of the case with an increased velocity. In the meantime,
the head continues in its flight and detonates on impact. This type
of shell is not used as extensively as the common shrapnel, and,
therefore, the common shrapnel shell alone will be taken up in the
following.

[Illustration: Fig. 2. Original Shell designed by Lieut. Henry Shrapnel
and Col. Boxer’s Improvement]


=The Explosive Charge.=--Reference to Fig. 1 will show that as far
as the construction of the shrapnel shell and case is concerned,
there is very little difference in those employed by the various
governments. Starting with the cases, it will be seen that these are
almost identical, except for length and the arrangement of the head for
carrying the detonating primer. There is a marked similarity in this
respect between the Russian, the British, and the German, and between
the American and the French. The form of the explosive charge held in
the brass case differs in almost every instance, but without exception
smokeless powder in some form or other is used. In the American shell,
nitrocellulose powder composed of multi-perforated cylindrical grains
each 0.35 inch long and 0.195 inch in diameter are used. In the Russian
case, smokeless powder of crystalline structure is used. In the German,
smokeless (nitrocellulose) powder in long sticks and arranged in
bundles is held in the case. The French use stick smokeless powder
¹⁄₂ millimeter (0.0195 inch) thick by 12.69 millimeters (¹⁄₂ inch)
wide. Two lengths or rows of this powder are arranged in the case.
The British use a smokeless powder of crystalline structure somewhat
similar to the Russian, but in some cases cordite has also been used,
although of late this type of powder has not been quite as commonly
employed.

The detonating agent or primer held in the head of the case varies in
almost every type of shrapnel. Practically all primers are provided
with “safety heads,” so that the shrapnel can be handled without danger
of premature explosion. The object, of course, of the detonating agent
or primer is to detonate or cause the sudden explosion of the explosive
charge in the shell for propelling the shrapnel out of the field gun.


=The Shrapnel Shell.=--The shell itself, as previously mentioned,
is made either from a forging or from bar stock. Forgings, however,
are used to a greater extent than bar stock, because the forged
shell is more homogeneous in its structure than the bar-stock shell,
and piping--a serious objection in the bar-stock shell--is entirely
eliminated. The shells used by the British, Russian, and German
governments are made almost exclusively from forgings, whereas those
used by the French and American governments are made both from forgings
and bar stock. When the French shell is made from bar stock, an
auxiliary base is screwed into it to eliminate any danger of piping.
Near the base of all shells is a groove in which a bronze or copper
band is hydraulically shrunk. This is afterward machined to the desired
shape and takes the rifling grooves in the gun so as to rotate the
shell when it is expelled. The body of the shell itself is slightly
smaller than the bore in the gun, and the rifling band, which is
larger and which is compressed into the rifling grooves, rotates the
projectile, thus keeping it in a straight line laterally during flight.
The bursting charge, which in practically all cases is common black
powder, is carried in the base of the shell and is usually enclosed
in a tin cup. Located above this is the diaphragm which is used for
carrying the lead bullets out of the shell when the bursting charge
explodes and distributes them in a fan shape. In most shells, upon
exploding, the nose blows out, stripping the threads that hold the
members together. It will, therefore, be seen that, in the explosion,
the entire fuse, fuse base, tube, diaphragm and bullets are all
ejected, the shell itself acting as a secondary cannon in the air.

The number of lead bullets carried in the 3-inch shrapnel shells ranges
from 210 to 360. In all cases, the lead bullets are about ¹⁄₂ inch in
diameter, weigh approximately 167 grains, and are kept from moving in
the shell by resin or other smoke-producing matrix. The matrix put
in with the lead bullets, in addition to keeping them from rattling,
is also used as a “tracer.” It is of importance in firing shrapnel
that the position of the explosion be plainly seen. With large shells
this is not difficult, but with shrapnel for field guns at long range
certain conditions of the atmosphere make it difficult to see when
the shell actually bursts. Various mixtures are used to overcome this
difficulty. In some cases, fine-grained black powder is compressed in
with the bullets in order to give the desired effect. In the German
shrapnel, a mixture of red amorphous phosphorus and fine-grained
powder which produces a dense white cloud of smoke is used, and in the
Russian, a mixture of magnesium antimony sulphide is used. The range of
a 3-inch shrapnel shell is about 6500 yards, and the muzzle velocity
of the quick-firing field gun ranges from 1700 on the American to 1930
feet per second on the Russian field gun. The duration of flight ranges
from 21 to 25 seconds.


=Development of Timing and Percussion Fuses.=--The first fuses used
in field ammunition were short iron or copper tubes filled with a
slow-burning composition. These were screwed into a fuse hole provided
in the shell, but there was no means for regulating the time of
burning. Later--about the end of the seventeenth century--the fuse
case was made of paper or wood so that by drilling a hole through into
the composition the fuse could be made to burn for approximately the
desired length of time before exploding the shell, or the fuse could be
cut to the correct length to accomplish the same purpose.

For a considerable time all attempts to produce a percussion fuse were
unsuccessful. Upon the discovery of fulminate of mercury in 1799,
the chief requirement of a percussion fuse was obtained. About fifty
years elapsed, however, before a satisfactory fuse was made. The
first percussion fuse was known as the Pettman fuse, and comprised a
roughened ball covered with detonating composition that was released
upon the discharge of the gun. When the shell hit the desired object,
the ball struck against the inner walls of the fuse, exploded the
composition and powder charge, thus bursting the shell. There are at
the present time three principal types of fuses in use: First, those
depending on gas pressure in the gun setting the pellet of the fuse
free--this is a base fuse; second, those relying on the shock of
discharge or the rotation of the shell to set the pellet free--used in
nose and base fuses; third, those depending on impact.

In shrapnel shells advantage is taken of two types of fuses, one of
which is the combination timing and percussion fuse used on common
shrapnel, and the other the combination timing and percussion fuse of
the high-explosive type used on high-explosive shrapnel. These types of
fuses are again sub-divided, but only in the manner of construction.
The most common fuse is that known as the combination timing and
percussion fuse of the double-banked type. This is used in practically
all shrapnel fuses except the French. The advantage of the double ring
of composition shown at _A_ and _B_ in Fig. 3 is to give a greater
length of composition and more accurate burning. Triple-banked and
quadruple-banked fuses on the same principle have been designed, but at
the present time have not been introduced.


=Operation of Combination Timing and Percussion Fuses.=--The manner
in which the combination timing and percussion fuse is regulated to
discharge the bursting charge in the shrapnel shell is interesting and
involves extremely difficult mathematical calculations. Before going
into the method of setting the fuse, it would probably be advisable
to describe briefly just how the fuse operates. As an example of the
double-banked fuse, Fig. 3 shows that adopted by the United States
government. The following description applies to this type of fuse.

[Illustration: Fig. 3. American Type of Combination Timing and
Percussion Fuse used on Shrapnel Shells]

Assume, first, that the timing ring is set at zero. The propelling
force given to the shrapnel shell in leaving the bore of the gun is
such as to sever the wire _C_ from plunger _G_. Plunger _G_ carries a
concussion primer which is discharged by hitting firing pin _D_. The
flame passes out through vent _E_, igniting the powder pellet _F_ and
the upper end of train _A_, and then through the vent _H_. From here,
the flame is transmitted to the lower timing ring _B_ through vent _I_
and the magazine _J_, and from there through the tube to the bursting
charge in the base of the shrapnel shell.

Assume any other setting, say 12 seconds. The vent _H_ is now changed
in position with respect to vent _F_ leading to the upper timing
train, and the vent _I_ leading to the powder magazine _J_ is also
changed. The flame, therefore, now passes through vent _E_ and burns
along the upper time train _A_ in a counterclockwise direction until
the vent _H_ is reached. It then passes down to the beginning of the
lower timing train and burns back in a clockwise direction to the
position of vent _I_, from which it is transmitted by the pellet of
compressed powder in this vent to the powder magazine _J_. It should be
understood that the annular grooves in the lower face of each timing
train do not form complete circles, a solid portion being left between
the grooves in the ends of each. This solid portion is used to obtain
a setting at which the fuse cannot be exploded and is known as the
“safety point.” As shown in Fig. 6, it is marked _S_ on the adjustable
timing ring.

[Illustration: Fig. 4. Russian Type of Combination Timing and
Percussion Fuse used on Shrapnel Shells]

The timing fuse shown in Fig. 3 is of the combination timing and
percussion type, and if the wire _C_ fails to release percussion
plunger _G_, the shell is exploded by means of a percussion fuse
which comes into use when the shell strikes. The percussive mechanism
consists of a primer _K_ held in an inverted position in the center
of the fuse body by a cup located beneath the percussive primer.
Percussion plunger _L_ works in a recess in the base of the fuse body
and is kept at the bottom of the recess away from contact with the
primer by a light spring in plunger _M_. The firing pin _N_ is mounted
on a fulcrumed pin, and is normally kept in the vertical position by
means of two side spring plungers. When the shell strikes, the impact
causes the plunger to snap up against the primer after compressing the
spring in pin _M_. This causes the firing of the primer _K_ and the
explosive charge passes out through a hole in the percussion plunger
chamber, not shown, to the magazine _J_ and from there down to the
powder in the base of the shell


=Russian Fuse.=--The Russian fuse shown in Fig. 4 differs only in a few
minor details from the American fuse, the chief difference being in
the arrangement of the percussive mechanisms. The percussive plunger
for the timing arrangement is kept up from the firing pin by means of
a spring bushing _E_ surrounding the body of the plunger. This bushing
is expanded by the plunger which is forced through it due to the force
of the shrapnel in leaving the bore of the gun. The spring _B_ in the
head of the fuse assists the plunger in expanding bushing _E_ and in
dropping down onto the firing pin _C_. The flame from the exploded
primer then travels down to the powder in the shell in practically the
same way that it does in the American fuse, except that the magazine
chamber is located at _D_ and explodes through the impact fuse chamber.
The percussive arrangement for setting the shell off by impact is
slightly different from that in the American fuse, in that the primer
and firing pin are held apart by means of springs, the inertia of which
is overcome when the shell strikes an object.


=French Fuse.=--With the exception of a few minor details, the timing
fuses used in American, Russian, British, German, Japanese, etc.,
shrapnel shells are the same. The French timing fuse, however, as shown
by the diagram Fig. 5, operates on an entirely different principle. In
this fuse, the firing for the timing train is contained in a sealed
tube of pure tin and is wound spirally around the head of the fuse.
Inside of the head is the ignition arrangement. To set the timing part
of this fuse, it is placed in a fuse-setting machine attached to the
field gun and, by forcing down a handle on this device, a piercing
point is thrust through the outer cap of the fuse, penetrating to the
interior space of the head as shown at _A_. Upon the discharge of
the shell from the gun, the gas pressure forces firing pin _B_ back,
hitting the percussive primer _C_. This causes a flame which passes out
through the opening previously punched at _A_ and ignites the “rope”
powder fuse which is wound around the head of the fuse body. This type
of fuse is also provided with a fuse which sets off the shell by impact
should the timing fuse fail to work. The head of the fuse is covered
with a cap with holes for the piercing point, and the whole cap can
be shifted around for a short distance and set by the corrector scale
marked on the body, as shown in Fig. 1. A projection on the cap engages
a recess in the fuse-setting machine and provides for this movement.

[Illustration: Fig. 5. French Type of Combination Timing and Percussion
Fuse]


=Firing of Shrapnel.=--The accuracy with which a shrapnel can be
exploded in the air at any desired point is remarkable, considering
the number of variable quantities that enter into the construction of
the timing fuse and powder train, etc. The calculations necessary for
finding the correct setting on the timing ring involve, however, the
use of higher mathematics and are consequently not within the scope of
this treatise.

In Fig. 6, the timing ring used on the American fuse is shown. Here
it will be seen that the ring is provided with twenty-one graduations
corresponding to twenty-one seconds in the duration of flight of the
projectile. It will also be noticed that the spacing of the graduations
differs. The reason for this is found in the relation of the vents,
the positions of the lower timing train, the trajectory of the flying
missile, and the decrease of velocity.

[Illustration: Fig. 6. Diagram showing how Timing Ring on the American
Combination Timing and Percussion Fuse is laid out]

Diagram Fig. 7 shows in an interesting manner just how a shrapnel is
fired. The range is approximately obtained by panoramic sights or
other means, and a test shell fired, the point of explosion noted, and
the necessary corrections made. A table which has been worked out for
different distances is then used. In Fig. 7 the diagram shown pertains
to the American quick-firing field gun having a muzzle velocity of 1700
feet per second and the American shrapnel of 3-inch size. It will be
noted that at 2000 yards the terminal velocity of the shrapnel is 1038
feet per second and the time of flight for the projectile 4.75 seconds.
In other words, the timing train to explode the shrapnel at this point
would be set at _A_ in Fig. 6. The range of a 3-inch American shrapnel
is 6500 yards and at this point the terminal velocity is approximately
724 feet per second, the time of flight 21.92 seconds. The shrapnel,
when exploded, shoots out the bullets at an increased velocity or from
250 to 300 feet per second, covering an area of about 250 by 30 yards,
half the bullets falling on the first 50 yards of the beaten zone.

[Illustration: Fig. 7. Diagram Illustrating Path of a Shrapnel and the
Time of Explosion at Various Distances]

In manufacturing shrapnel shells, a test shell is taken from every 120
shells, which is actually fired out of a quick-firing gun into a bank
of sand. If the contour of the shell in the neighborhood of the powder
pocket is expanded during this test, the shell is discarded because of
the liability of tearing out the rifling grooves in the gun


=Propellants and Explosives used in Shrapnel and High-explosive
Shells.=--As has been previously explained, a shrapnel shell contains
three principal parts, _viz._, the projectile that carries the
destructive charge of lead bullets, the fuse that carries a detonating
arrangement for exploding the charge in the base of the projectile,
and the cartridge case that carries the powder charge used in
propelling the projectile out of the bore of the gun. A high-explosive
shell also comprises three principal parts, but the projectile,
instead of carrying a charge of bullets and black powder, is filled
with a high-explosive material, which, when detonated, bursts the body
of the projectile into small pieces that are thrown off with great
velocity and destructive effect. Shrapnel is used against troops in
the open field, whereas high-explosive shells, which may be either
of the ordinary or of the armor-piercing type, are used against
fortifications, etc


=Classification of Explosives.=--The explosives used in shrapnel and
high-explosive shells may be divided into three general classes: 1.
Progressive or propelling explosives--known as “low” explosives. 2.
Detonating or disruptive explosives--known as “high” explosives. 3.
Detonators--known as “fulminates.” The first of these includes black
gun powder, smokeless powder, and black blasting powder. The second,
dynamite, nitroglycerine, gun cotton, etc. The third includes chiefly
fulminates and chlorates. In all classes of explosives, the effect
of the explosion is dependent upon the quantity of gas and the heat
developed per unit of weight and volume of the explosive, the rapidity
of the reaction, and the character of the confinement, if any, of the
explosive charge.

_Low Explosives._--For certain explosives, such as smokeless powder,
the explosive action does not differ in principle from the burning
of a piece of wood or other combustible material. The combustion is
very rapid, but is a surface action, progressing from layer to layer
until the entire grain is consumed. Such materials are known as “low”
explosives, although the power developed through the combustion of
a unit weight may be very great. The progressive emission of gas
from a low explosive, such as burning gun powder, produces a pushing
effect upon a projectile without unduly straining the gun, whereas
the sudden conversion of an equal weight of a high explosive, such
as nitroglycerine, into gas, would develop such high pressures as to
rupture the gun.

_High Explosives._--In high explosives, such as nitroglycerine, gun
cotton, picric acid, etc., the progress of the explosive reaction
is not by burning from layer to layer, but, instead, consists of an
initial breaking up of the molecules, giving rise to an explosive wave,
which is transmitted with great velocity in all directions throughout
the mass, and causes it to be converted almost instantly into a gas.
The velocity of this explosive wave has been determined, for some
materials, to be more than 20,000 feet, or approximately four miles,
per second.

_Detonators or Fulminates._--The action of fulminates is much more
powerful than either the low or high explosives described. They can
be readily detonated by slight shock or by the application of heat,
and are used in primers, for setting off the propelling charge in a
cartridge case, and in fuses, either of the plain percussion or of
the combination time and percussion types. The most common fulminate
is made by dissolving mercury in strong nitric acid and then pouring
the solution into alcohol. After an apparently violent reaction, a
mass of fine, gray crystals of fulminate of mercury is produced. The
crystalline powder thus produced is washed with water to free it from
acid and is then mixed with glass ground to a fine powder. Because of
its extreme sensitiveness to heat produced by the slightest friction,
it is usually kept soaked in water or alcohol until needed


=Manufacture of Black Powder.=--Black powder, because of its “pushing”
effect when exploded, is used extensively as a base charge for shrapnel
shells in expelling the bullets from the projectile. It comprises
three principal elements in about the following proportions: 75
parts of saltpeter, 15 parts of charcoal, and 10 parts of sulphur.
These ingredients must be absolutely free from impurities and, in
manufacturing, great care is taken in refining the saltpeter and
sulphur, and in burning the charcoal, to prevent the introduction
of any foreign substances. After purification, the ingredients are
carefully weighed in the proper proportions and mixed for about 5
minutes in a revolving drum provided with mixing arms. The mixed
charge is now ground for several hours, the charge being moistened
occasionally with distilled water, the resulting mixture being what
is called a “milk cake.” It is then reduced to fine meal in a machine
having Tobin bronze or gun-metal rollers, after which it is compressed
under hydraulic pressure.

The next operation comprises the granulating of the powder, which is
done in a strong Tobin bronze or gun-metal framework carrying two pairs
of toothed and two pairs of plain Tobin bronze or gun-metal rollers.
The “cake” is cut into pieces by these rollers and falls on screens
which sift it into grains of the required size. The grains are then
separated from the dust in a revolving screen, and the high polish or
glaze is produced by putting the powder into drums or glazing barrels,
which revolve constantly for several hours. Graphite is generally used
to provide the glazing effect. The powder is now dried in a stove
heated by steam pipes, and is spread upon canvas trays placed on shelves


=Manufacture of Smokeless Powder.=--Smokeless powder, which is used
in various forms in cartridge cases, was discovered in 1846 by a
German chemist Schoenbein. The chief ingredient of smokeless powder
is cotton. The portion of cotton used is generally the short fiber.
The first attempts to produce gun cotton were unsatisfactory, and
several very serious explosions occurred. Many of the difficulties in
its manufacture were overcome by an Austrian, von Lenk. Still further
progress was made by a Swedish engineer, Alfred Nobel, and the improved
explosive was patented in 1888 under the name of “ballistite.” One of
the principal smokeless powders is known as “cordite”, this name being
derived from the cord-like form it assumes in manufacture. The first
compositions of cordite were: 58 per cent of nitroglycerine; 37 per
cent of gun cotton; and 5 per cent of mineral jelly. This composition,
after considerable use, was found to have a slight deteriorating effect
on the bore of the gun, and after ten years’ use was modified to the
following proportions: 30 per cent of nitroglycerine; 65 per cent of
gun cotton; and 5 per cent of mineral jelly.

The brand of smokeless powder used most extensively as a propelling
charge in shrapnel or high-explosive shells is known as nitrocellulose,
and, as is common with cordite, the base of this is cotton, as
previously explained. It is manufactured as follows: After bleaching
and purifying, the cotton is run through a picker which opens up the
fibers and breaks up any lumps. It is then thoroughly dried and is
ready for nitration. The most generally used method of nitration is
to put the cotton into a large vessel filled with a mixture of nitric
and sulphuric acids. The sulphuric acid absorbs the water developed
in the process of nitration, which would otherwise too greatly dilute
the nitric acid. After a few minutes’ immersion, the pot is rapidly
rotated by power, and the acid permitted to escape. Following this,
the nitrated cotton is washed for a short time and then removed from
the nitrator or pot and repeatedly washed or boiled to remove all
traces of free acid. As the keeping qualities of the nitrated cotton
are dependent upon the thoroughness with which it is purified, the
specifications for powder for the United States army and navy require
that the nitrocellulose shall be given at least five boilings at this
stage of the manufacture, with a change of water after each boiling,
the total time of boiling being forty hours. Following this preliminary
purification, the nitrocellulose is cut up into shorter lengths, by
being rapidly run between cylinders carrying revolving knives. This
operation--known as “pulping”--is necessary because of the difficulty
experienced in removing the free acid, unless the fibers are cut up
into short lengths.

After pulping, the nitrocellulose is given six more boilings, with a
change of water after each, followed by ten cold water washings. The
material is now known as gun cotton or pyrocellulose. Previous to
adding the solvent, this must be free from water. This is generally
accomplished in a circular wringer, and in addition by compressing
the pyrocellulose into solid blocks. Alcohol is forced through the
compressed mass. Ether is then added to the pyrocellulose already
impregnated with alcohol, the relative proportions being two parts,
by volume, of ether to one part of alcohol. After the ether has been
thoroughly incorporated in a kneading machine, the material is placed
in a hydraulic press and formed into cylindrical blocks about 10 inches
in diameter and 15 inches long. It is then transferred to a finishing
press where it is again forced through dies and comes out in the form
of long strips or rods, which are cut into pieces of the length and
widths required. It is in this finishing process that the various
governments differ in their methods of manufacture. The United States
Government uses a short perforated circular block, whereas the French
use flat sticks about 0.0195 inch thick by ¹⁄₂ inch wide. Two lengths
or rows of these sticks are arranged in the cartridge case. The cut
up pieces are subjected to a drying process which removes nearly all
the solvent and leaves the material in a suitable condition for use.
The drying process is a lengthy one, amounting to as much as four or
five months for powder in large pieces. Upon completion, the powder is
blended and packed in airtight boxes


=Manufacture of High Explosives.=--The explosive charges used in
high-explosive shells are known by various trade names, such as:
emmensite, lyddite, melinite, maximite, nitrobenzole, nitronaphthalene,
shimose, trinitrotoluol, turpenite, etc. The base of such explosives as
emmensite, maximite, lyddite, melinite, and shimose, is picric acid,
which is secured from coal tar, subjected to fractional distillation.
The liquid which comes off when this is raised to a temperature of
150 degrees C. is called “light” oil, and when these light oils
have been again distilled, the next fraction or “middle” oil yields
phenol or carbolic acid. This substance when nitrated gives off
picric acid. Experiments with lyddite shells showed their behavior
to be very erratic, some exploding with great effect, while others
gave disappointing results. This was due to the fact that picric
acid requires a powerful detonator to obtain the highest explosive
effect. The use of such a detonator, however, is dangerous, and
extensive experiments have brought forth a new high explosive known as
trinitrotoluol--generally termed T.N.T. Although the explosive force of
trinitrotoluol is slightly less than that of picric acid, the pressure
of the latter being 135,820 pounds per square inch as against 119,000
pounds for trinitrotoluol, its advantages more than compensate for the
difference.

Trinitrotoluol is obtained by the nitration of toluene, contained in
the crude benzol distilled from coal tar and washed out from coal gas.
The crude benzol contains roughly:


                    Per cent
    Benzine            50
    Toluene            36
    Xylene             11
    Other substances    3


Toluene to be used for the manufacture of trinitrotoluol should be a
clear water-like liquid, free from suspended solid matter, and having a
specific gravity of not less than 0.868, nor more than 0.870, at 15.5
degrees C. Trinitrotoluol when pure has no odor and is a yellowish
crystalline powder which darkens slightly with age. It cannot be
exploded by flame or strong percussion, and a rifle bullet may be
fired through it without any effect. When heated to 180 degrees C., it
ignites and burns with a heavy black smoke; but when detonated by a
fulminate of mercury detonator, it explodes with great violence, giving
off a black smoke. Shells containing this explosive, first used on the
western battle front, were given such names as “coal boxes,” “Jack
Johnsons,” “Black Marias,” etc., by the allies.

The Russians and Austrians use a high explosive known as ammonal in
which 12 to 15 per cent of trinitrotoluol is mixed with an oxidizing
compound, ammonium nitrate, a small amount of aluminum powder, and a
trace of charcoal. This high explosive gives somewhat better results
than plain trinitrotoluol, but has the one disadvantage of easily
collecting moisture, and consequently must be made up in airtight
cartridges. The British are now using an improved compound of this
character, which is so prepared that trouble is not experienced with
the collection of moisture.




CHAPTER II

FORGING SHRAPNEL SHELLS


Within the last few months, many methods have been suggested for making
shrapnel forgings, but a comparatively small number have been put into
use. Practically speaking, no two governments have adopted the same
method. The Russian government uses double-acting horizontal hydraulic
forging presses in which two operations are performed at the same time
on different forgings. For instance, while the punch in one end of
the machine is piercing a heated billet, the ram on the return stroke
performs the hot drawing operation on another shell located at the
opposite end of the machine. In this way a shell is completed at each
cycle of the machine--forward and return stroke. The French government,
up to a short time ago, used steam hammers for this purpose, and
produced shrapnel forgings in practically the same manner as a
drop-forging is made, the punch being carried in the ram of the press
and the die held on the bed. This is rather a slow process and requires
more than one heating to complete the forging. The German government
uses a horizontal hydraulic forging press for piercing the billet and
a steam driven machine for drawing the forging, which receives its
motion from a rack and pinion. This method has the advantage over the
hydraulic press of being more economical in the consumption of power.

The methods followed by different concerns in this country and Canada,
at the present time, differ to a large extent. Some manufacturers are
using a method that dates back as far as 1890, as will be described
later. Others are using a more improved method developed about 1895,
whereas about three concerns are using a still more improved method
developed within the past year


=Caley Method of Making Shrapnel Forgings.=--The first method (known
as the Caley process) of making shrapnel forgings in this country had
its inception about 1890 and was used almost exclusively until 1895.
This comprised a slug-forming and billet-piercing operation followed by
a successive reduction and elongation of the forging through drawing
dies. The order of these operations is shown diagrammatically in Fig.
1. The information given herewith pertains to the making of a forging
for a 3-inch shrapnel shell. As shown at _D_, a billet of steel 3¹⁄₄
inches in diameter and 6¹⁄₂ inches long was cut off from a bar with
a cold saw, and formed into a cone shape under a vertical hydraulic
press having a capacity of 100 tons. The billet was heated in a furnace
to about 1900 degrees F., dropped into the impression in the die and
forced into shape by a hydraulic plunger having a depression in the
lower end which centered the blank. The result of this operation is
shown at _F_.

[Illustration: Fig. 1. Diagram showing Caley Process of making Shrapnel
Forgings in Hydraulic Forging Presses]

[Illustration: Fig. 2. Watson-Stillman Hydraulic Forging Press of the
Vertical Type used for making Shrapnel Forgings]

The next step was to anneal the billet, after which it was pierced as
shown at _C_, and at the same time slightly elongated. This operation
was handled in a hydraulic press of the type shown in Fig. 2. On a 0.70
per cent carbon steel billet the pressure on the punch in the piercing
operation was 20,000 pounds per square inch, and the machine used was
a vertical hydraulic forging press of the type referred to having a
capacity of 100 tons. From the piercing operation the forging was
taken direct without annealing to the horizontal hydraulic draw press,
and, as is shown at _H_, was located on a punch and forced through a
series of drawing dies which gradually reduced the shell to the correct
diameter, 3¹⁄₈ inches, and drew it out to the required length, about
8³⁄₄ inches.

A point worthy of attention is the preparation of the cone-shaped
billet. The smallest end was made slightly smaller than the smallest
reduction die in the series. The reason for this was that if any
drawing were done on the end of the shell the front corner would be
drawn over and deformed, increasing the amount of machining required.
The drawing dies in this case were six in number, as shown at _H_,
and were reduced on a sliding scale of the following proportional
reductions. First, 0.100 inch; second, 0.080 inch; third, 0.060 inch;
fourth, 0.040 inch; fifth, 0.030 inch; and sixth, 0.020 inch. This gave
dies of the following sizes, in inches, starting with the largest in
the series: 3.355, 3.275, 3.215, 3.175, 3.145, and 3.125.

The shape given to the drawing edges of the dies is of prime
importance. The mouth or entering side of the hole was beveled to an
angle of 20 degrees leading to a liberal curve which terminated in
a land ¹⁄₁₆ inch wide. The shape was finished off with a ¹⁄₄-inch
radius. These dies were made from chilled cast iron and were held in
position as shown at _H_, being slipped into a pocket in the frame of
the machine, as shown at _I_. The punches for the coning, piercing and
hot drawing operations were made from special hot punching steel. The
first drawing die in the series lasted the longest because the metal
was hotter at this point than when it was drawn completely through the
dies. As a rule, the last drawing die turned out 100 shells before
being worn or scored. Then it was reground to a larger size and used
again. The drawing punch was lubricated occasionally with graphite.
After drawing, the forging is annealed to obtain the proper physical
qualities. This method of making forgings for a 3-inch shrapnel shell
is capable of producing 400 in ten hours.

[Illustration: Fig. 3. Holinger Process of making Shrapnel Forgings]


=Holinger Method of Making Shrapnel Forgings.=--About 1895 the
following method, known as the Holinger process of making shrapnel
forgings, was devised. Instead of making the billet conical in shape
before piercing, this preliminary operation was dispensed with, and to
facilitate the work, as well as to reduce the friction of the flowing
metal, the arrangement of the piercing punch and die was changed. This
process is shown in Figs. 3 and 4, and was accomplished in a hydraulic
press provided with two cylinders, one located at the bottom and the
other at the top of the press.

The operation was as follows: The die _a_ was held in a movable frame
_b_ and the piston _c_ acted first. The first position after the billet
was dropped into the die is shown at _B_. Here the die _a_ and punch
_d_ remained stationary while the piston _c_ descended, pushing the
billet through the die and over the punch. When the piston reached
the end of its stroke, as shown at _C_, the lower cylinder began to
act and the frame carrying the die was raised. This frame, as shown
at _D_, carried a stripper plate _e_ which removed the pierced billet
from the punch and located it so that it could be picked off with a
pair of tongs. A subsequent operation of hot drawing as shown at _E_,
Fig. 4, was required, which is similar to that described in the first
method. The method just described was used chiefly for 6- and 8-inch
shrapnel and projectile forgings, and at the present time is still used
for 3- and 6-inch shell forgings. It requires much less power and turns
out a better and more concentric forging than the method previously
described. The production on 8-inch shells is about 180 in ten hours,
and 250 on the 3-inch shell.

[Illustration: Fig. 4. Holinger Process of making Shrapnel Forgings]

[Illustration: Fig. 5. Improved Method of making Shrapnel Forgings in
One Heat and One Operation]


=Later Methods of Forging Shrapnel Shells.=--The increased demand for
shrapnel within the last few months has been instrumental in bringing
about a radical improvement in the production of forged shells.
Previously, the aim was to get the internal diameter as close as
possible to the finished size and to do comparatively little machining
on it; in fact, this is still, in a great number of cases, one of the
requirements. While at first glance this would appear to be the logical
way of handling the work, on further investigation it is found that
the forging of the shell to the correct size is much more expensive
than to leave sufficient metal to machine all over. In the first place,
a hydraulic machine of 100 tons capacity costs considerably more in
initial outlay than a turret lathe, and in the second place it is more
expensive to operate. The cheapest method of making a shrapnel forging
is to rough-forge it to approximately the correct shape and then finish
to exact shape and diameter in turret lathes or semi-automatic chucking
machines. This simplifies the forging process and also decreases the
production costs.

One of the later methods of making shrapnel forgings is shown
diagrammatically in Fig. 5. A billet of steel 6¹⁄₂ inches long by 3⁵⁄₁₆
inches in diameter is heated to a temperature of from 1900 to 2100
degrees F., and then dropped into the impression in the die _a_ held in
a special cast-steel die-holder _b_. To do this, die _a_ is drawn out
from beneath the punch, punch guide _c_ removed, and the billet dropped
in. Then the guide is replaced and the die-holder slid in until it
contacts with the stop _d_. The press is now operated, and, as shown at
_B_, advances, piercing the billet and making the metal flow up around
the walls of the punch.

The punch now retreats, carrying the centralizing guide _c_ with
it. The die-holder is now drawn out from under the punch onto a
bracket projecting from the bed of the press. The high-carbon steel,
hardened block _e_ then drops out of the die, as is also the case
with the finished forging. This block _e_, of course, is heated up
to a considerable extent due to the hot metal resting on it so that
several blocks of this kind are provided. In the illustration, as
shown at _C_, centralizing guide _c_ is shown attached to the punch.
In actual operation this is not the case. When the punch rises, guide
_c_ is stripped from it by stripper plate _f_ so that the guide is
gripped with tongs and laid down on the bed of the press until a fresh
heated billet has been placed in the die impression ready for the next
piercing. The punch is made from special hot punching steel and the die
from chilled cast iron. The production of forgings by this method for a
3-inch shrapnel shell is about 600 in ten hours.

[Illustration: Fig. 6. Producing Shrapnel Forgings in a 750-ton
Hydraulic Forging Press]

The amount of metal left for machining by this method varies from
¹⁄₈ to ³⁄₁₆ inch on the internal and external diameters. The forging
after annealing is then machined inside and out on turret lathes,
or semi-automatic chucking machines. The accepted method is to first
machine the internal diameter and then hold the shell on an expanding
arbor and machine it on the external diameter.

[Illustration: Fig. 7. Piercing Billets for Shrapnel Forgings In a
“Wood” 750-ton Hydraulic Forging Press]


=Producing Shrapnel Forgings in Hydraulic Presses.=--In the foregoing
description various principles of making shrapnel forgings were
described. Owing to the large number of forgings lately required,
practically all types of forging presses and power forging machines
have been used. Fig. 6 shows how one manufacturer is solving the
problem. The machine used is an R. D. Wood Co., 750-ton hydraulic
forging press; this performs both the billet piercing and drawing
operations. The forgings turned out on this machine are for the British
18-pound shell, and the billet is 3¹⁄₂ inches in diameter by 4¹⁄₂
inches long. The first operation, piercing the billet, is done by the
punches and dies shown in Fig. 7. The billet is heated in a furnace to
a temperature of 2000 degrees F., and then quickly removed and placed
in the dies. The press is now operated, piercing two billets at the
same time. The pierced billet is 3¹⁄₂ inches in diameter by 7¹⁄₂ inches
long.

A complete batch of pierced billets is first put through, then the
pierced billets are taken to the furnace again and heated to 2000
degrees F. The punches and dies in the center of the illustration Fig.
8 are used for finish-drawing the forging by drawing it out to 3¹⁄₂
inches in diameter by 11 inches long. This method is only temporary
and will be replaced shortly by three R. D. Wood four-post hydraulic
presses. The piercing operation will be handled on one press of 350
tons capacity, and the drawing operations on two presses of 200 tons
capacity.

[Illustration: Fig. 8. Drawing Shrapnel Forgings in a “Wood” 750-ton
Hydraulic Forging Press]


=Making Shrapnel Forgings in Power Forging Machines.=--One of the
latest developments in the art of producing forgings for shrapnel
shells is the adaptation of the power forging machine to this work. As
has been previously mentioned, there are several methods of producing
shrapnel shells, and as it has been conclusively proved that the
forged shell is superior to the shell made from bar stock, it is
only natural that several methods for making the forgings would be
developed. In the forging machine method, a bar slightly larger than
the finished diameter of the forging is cut off, making a billet about
5¹⁄₂ inches long. This billet, for a 3-inch shell, weighs about 9¹⁄₄ to
9¹⁄₂ pounds.

[Illustration: Fig. 9. Examples of Shrapnel Forgings turned out on a
Power Forging Machine]

The billet is heated to a white heat in a furnace, the temperature
being about 2000 degrees F., depending on the carbon content and
other constituents in the steel, and is then placed in the lower
impression of the forging die. The machine used for this size of
forging is a standard upsetting and forging machine provided with a
special crank-shaft. Upon being operated, the lower plunger, which is
larger than the diameter of the powder pocket in the shell, advances
and pierces the billet. The pierced billet is then raised to the next
impression, and the machine again operated. The second punch is longer
than the first and smaller in diameter. The billet is forced up on this
punch, which reduces it in diameter and increases its length. After
the second impression the partially formed shell is then placed in
the third or final die impression, where it is given two blows, being
given one-half turn after the first blow to form it more perfectly. The
operations just enumerated are performed in one heating of the billet,
and the production of a 3-inch shell ranges from 400 to 450 in ten
hours.

The dies for this work are, of course, constructed upon a somewhat
different principle from the ordinary forging die, because in this case
it is necessary to make the metal flow up on the punches. The dies,
therefore, are so constructed that they recede as the punch advances,
which tends to make the metal flow up on the punch. The practicability
of this method is well illustrated by the samples shown in Fig. 9. Here
_D_ is the rough forging just as it comes from the machine, with the
exception that the mouth has been trimmed. _C_ is a section of a shell
made from low-carbon steel about 0.30 per cent carbon; _B_ is a shell
made from 0.50 per cent carbon, 3¹⁄₂ per cent nickel steel. This has
been rough-turned, as the illustration shows. The homogeneity of the
forgings is clearly indicated. _A_ is a forging made from low-carbon
steel, finish-turned.

One of the most interesting points about this method is its cost as
compared with shells made from bar stock. To produce a 3-inch shell
from bar stock requires about 22 pounds of material, and on metal
costing 10 cents per pound, a bar shell--exclusive of machining--costs
$2.20; to produce the same shell on a power forging machine requires
about 9¹⁄₄ to 9¹⁄₂ pounds, and figuring on 10 cents per pound the
cost for the material is only $1--a saving of $1.20 on each shell.
Furthermore, the production of shells from bar stock on automatic
machines is about twelve to fifteen per day. The number of forgings
that can be turned out in the same time is 400 to 450, and the number
that can be machined in this time varies from forty to fifty for two
operations. It is therefore evident that the production of shells by
forging is far superior to the bar method, and the forged shell is more
satisfactory from every standpoint.

[Illustration: Fig. 10. Diagram Illustrating Method of piercing and
drawing Shrapnel Forgings in a Bliss Power Press]


=Forging Shrapnel in a Power Press.=--Another interesting development
in the forging line is shown diagrammatically in Fig. 10. This method
comprises three operations, and is handled in a No. 80¹⁄₂ Bliss press
capable of exerting a pressure of 1200 tons. A billet 3¹⁄₄ inches in
diameter by 3³⁄₄ inches long is heated in a furnace to 1976 degrees
F. and then quickly placed in the die shown at _A_. The press is
operated, and the punch in descending pierces the billet, being guided
by the guide _a_, as shown at _B_, which also acts as a stripper. The
forging retains its heat to a certain extent after this operation, the
temperature being about from 1380 to 1425 degrees F. This is sufficient
to perform the second minor operation which, as shown at _C_ and _D_,
consists in forcing the heated billet into the die-block to reduce the
diameter of the lower end and facilitate the succeeding operation. This
reducing operation is performed with the same type of punch as is used
in the succeeding operation, and the die-block is simply laid on top of
a bolster while the reducing is being done.

The final forming or drawing of the forging is accomplished as shown at
_E_ and _F_, the same type of press, _viz._, a Bliss No. 80¹⁄₂ power
press, being used for this purpose. The pierced billet is now heated
to 1976 degrees F., and is then forced through the three drawing dies
_b_, _c_ and _d_, by the punch _e_. The first die is 3⁵⁄₁₆ inches in
diameter and reduces the forging from 3³⁄₈ inches to this size. The
second is 3⁷⁄₃₂, and the third, or last, 3¹⁄₈ inches in diameter.
The forging, after being forced through the dies, is stripped from
the punch by plates _f_, and as it still retains a temperature of
1475 degrees F.--sufficient for annealing--is thrown down on the
sand to cool off. The billet piercing and drawing dies, shown in the
illustration, were made from 50-point carbon steel, hardened. This gave
fair results, although chilled cast-iron dies would prove even more
satisfactory. The punches were made from several different materials
such as chrome-vanadium, 70-point carbon steel, and unannealed
malleable casting. Of the three materials, the latter gave the most
satisfactory results, in that pitting was reduced to a minimum. Of
course, it was necessary to grind the malleable casting to shape.


=Flow of Hot Metal When Pierced.=--In the manufacture of shrapnel shell
forgings, the first operation is that of piercing, and to accomplish
this satisfactorily, it is necessary to understand the action of a
piercing punch on a semi-plastic billet of steel. There are certain
fundamental laws governing the flow of metals under pressure and a
study of these is of exceptional interest. An attempt has been made
in Fig. 11 to illustrate diagrammatically some of the principles
involved, and in the following discussion it should be understood that
the billet is made from 50-point carbon, 60-point manganese steel, 6¹⁄₂
by 3⁵⁄₁₆ inches in diameter.

At _A_ a round-end tapered punch is shown in contact with the heated
billet, and the lines show the possible flow of the metal, _i.e._, the
material commences to “pack” at the end of the punch. In this case the
walls of the die are straight. At _B_ the billet is being pierced,
and the resultant effect on the flow of the metal is indicated. Here
it will be seen that the pressure increases as the punch descends,
because of the wedging action on the metal and the friction between the
surfaces of the sides of the punch and die. The pressure on the end of
a punch of this shape is about 20,000 pounds per square inch.

[Illustration: Fig. 11. Diagram Illustrating Flow of Hot Metal while
being pierced]

By leaving the sides of the die of the same shape as at _B_, but
making the end of the punch square instead of round and not tapered,
different action is caused. When the flat punch, as shown at _C_, first
contacts with the metal, the pressure required is greater than at _A_,
but as soon as the metal commences to flow as at _D_, the pressure
decreases. For instance, suppose the pressure required at _B_ to pierce
the billet was 100 tons; on the same material at _D_, the required
pressure would be only 70 tons--a decrease of 30 per cent. The metal,
however, does not follow the sides of the punch as closely at _D_ as
at _B_, and this accounts in part for the reduction of power required.
The action of hot flowing metal on the face of a square punch is just
the reverse of what would naturally be expected. Instead of the punch
wearing away at the edge, the center first shows signs of wear as
indicated at _e_. Seams are opened up in a radial direction caused by
the hot metal attacking the softest parts in the face of the punch.

[Illustration: Fig. 12. Shrapnel Shell Head and Diaphragm produced in a
Power Forging Machine]

Again, a different condition exists to that shown at _B_ and _D_,
when both the die and the punch are tapered as shown at _E_. Here the
friction of the extruded metal on the walls of the die and sides of
the punch is excessive, and it is practically impossible to produce
a satisfactorily pierced billet in this manner. From a theoretical
standpoint, the conditions shown at _F_ are ideal. Here the sides of
the punch are straight, the end flat, and the walls of the die taper
or increase in diameter toward the bottom. In this case the friction
of the flowing metal is greatly reduced because of the lessening of
the wedging action. Other considerations, however, make this method
impracticable.

[Illustration: Fig. 13. Diagram Illustrating Method of producing
Shrapnel Shell Heads in a Power Forging Machine without any Waste of
Stock]

A still greater reduction in the pressure necessary to pierce a billet
is shown at _G_. Here a square billet instead of a round one is being
pierced. In the plan view it will be noticed that the friction on the
walls of the die is greatly reduced, and the pressure continues low
until the extruded billet contacts all around with the surface of the
die. The completed product, however, is inferior to that made from a
round billet. From the previous remarks, it will be seen that a punch
and die that would best meet the requirements is one having a rounded
end as at _B_, straight sides as at _D_, and straight walls in the die.
The most satisfactory punch and die for piercing shrapnel forgings when
all the variable conditions are considered would be as shown at _H_.

[Illustration: Fig. 14. Diagram Illustrating Method of making Shrapnel
Shell Diaphragms in a Special Type of Power Forging Machine]


=Forging the Shrapnel Head.=--The shrapnel head shown at _A_ in Fig.
12, that screws into the end of the shell and into which the fuse body
is screwed, is made from a forging of low-carbon steel for the French
shell. One method of producing this, which is of unusual interest,
is shown in Fig. 13. A power-driven forging machine equipped with a
special set of tools is used for this purpose. A bar of steel of the
same diameter as the hole in the finished forging, in this case 1¹⁄₂
inch, is gripped in the dies as shown at _A_, and is upset by means
of a plunger _a_, forming an upset on the end of the bar shown to
the right. The upset bar is now placed in the second impression of
the gripping dies, as shown at _B_. By way of explanation, it should
be stated that the views of the dies shown at _A_, _B_, and _C_ are
sections taken in a horizontal plane at each stage or die impression.
Upon gripping the upset forging in the second impression in the dies,
the plunger _b_ advances and forms an annular groove in the face of the
forging, at the same time increasing its width as shown at _c_.

The forging, still integral with the bar, is now quickly removed and
placed in the last impression of the dies. The diameter of the hole
in these dies is larger than the bar, allowing it to slip back as
the punch advances to punch the hole in the forging. When the punch
moves forward it carries with it the spring-operated sleeve _d_, thus
finishing the forging in one heat. This method of forging is very
satisfactory, producing a homogeneous forging at the rate of 1500 in
ten hours.


=Forging the Steel Diaphragm.=--The steel diaphragm shown at _B_ in
Fig. 12 is made from low-carbon steel in a special type of forging
machine operated similarly to a hot-pressed nut machine. That is to
say, the bar, instead of being fed in from the front, as in a regular
forging machine, is fed in from the side. The manner in which this is
accomplished is shown in Fig. 14. A flat bar of steel 2³⁄₈ inches wide
by ³⁄₈ inch thick, heated to the proper temperature for a distance of
three feet, is fed across the face of the die as at _A_ and located by
stop _b_. Punch _c_ then advances and cuts out a blank of the required
diameter, forcing it into the die, as shown at _B_. The metal is now
confined between the faces of punches _d_ and _c_ and in die _a_, and
is forged to the required shape. The next step is shown at _C_, where
punch _d_ advances and forces the formed forging out of the die. The
production of this diaphragm is in the neighborhood of from 8000 to
10,000 in ten hours.




CHAPTER III

MACHINING AND HEAT-TREATMENT OF SHRAPNEL SHELLS


[Illustration: Fig. 1. Shrapnel Shells in Various Stages of Manufacture]

Shrapnel shells are manufactured either from bar stock or forgings. The
bar-stock method, however, is not considered as satisfactory as forging
because of piping, so that the greater number of shrapnel shells made
at the present time are turned out from forgings. The first step,
therefore, in the making of a shrapnel shell is to cut off a billet of
the required length from a bar of steel of the necessary constituents.
In the making of an 18-pound shrapnel shell, the billet is cut off
from a bar of 46-point carbon, 60-point manganese steel in machines of
different types. One way of doing this, as shown in Fig. 2, is to use a
Newton cutting-off machine having an air clamp for holding the bar in
place while it is being cut off. A Hunter duplex saw, as shown in the
illustration, provided with high-speed steel inserted teeth, performs
the cutting operation. The billet for an 18-pound shrapnel shell is
3¹⁄₂ inches in diameter by 4¹⁄₂ inches long. It is then forged to
shape, as has been previously explained.

Assuming that the forging has been completed, the following is a
complete summary of the machining operations on the shell up to the
point of assembling. In one plant where this work is being done, the
shrapnel shells are put through in lots of 120, each lot being kept
in three boxes, forty shells to a box. Out of every 120, one shell
after heat-treatment is tested for tensile strength. The tensile
strength before heat-treatment must be from 30,000 to 40,000 pounds per
square inch, and from 80,000 to 90,000 pounds per square inch after
heat-treatment. For facilitating transportation, trucks of various
designs are used. One type of truck used for this purpose is shown in
Fig. 3. This is built by the Chapman Double Ball Bearing Co. of Canada,
Ltd., Toronto, Ontario, and has some interesting features, the chief of
which are the ball-bearing swiveling head, ball-bearing wheels, and the
means of releasing or raising the load with the handle in any position.
This feature is valuable in using the truck in a crowded space.

[Illustration: Fig. 2. Cutting off Billets for making Shrapnel Forgings
in a Newton Cutting-off Machine]


=Trimming and Facing the Shell Forging.=--The first machining operation
on the forged shell is to cut off the ragged end, which is generally
from ¹⁄₂ to 1¹⁄₂ inch longer than that required for the finished shell.
This operation is performed in many different ways, but one of the
most common is to place it in a Hurlbut-Rogers cutting-off machine as
shown in Fig. 4. For performing the cutting-off operation, two plain
forged cutting-off tools made from “Sabine” extra high-speed steel are
used. The forging is located in the proper position in the chuck by
a plunger or stop _A_, sliding in a fixture _B_ clamped to the base
of the machine. This plunger locates the shell from the bottom of the
hole or powder pocket and forces the shell into the chuck against the
resistance of an open-wound spring. The stop is then located by a gage
_C_ that forms a member of the fixture and fitting ring _D_ on the
stop. The chuck jaws are now clamped on the work and the cutting off
commences. As soon as the excess stock is cut off, the stop is drawn
back and the pressure of the jaws on the work released; the spring in
the chuck then ejects the forging. The production of an 18-pound shell
from one machine is about 140 in eight hours.

[Illustration: Fig. 3. Truck built by the Chapman Double Ball Bearing
Co. for transferring Shrapnel Shells about the Shop]

The next roughing operation is to face off the bottom or closed end of
the forging, bringing the shell to approximately the correct length.
There are also many ways of performing this operation. One method is to
grip the forging in a chuck, as shown in Fig. 5, in an ordinary lathe
and face off the end with a high-speed steel tool held in an Armstrong
tool-holder. From to ¹⁄₄ to ³⁄₈ inch is faced off from the end.

[Illustration: Fig. 4. Cutting off Excess Length of Shrapnel Forging in
a Hurlbut-Rogers Cutting-off Machine]

[Illustration: Fig. 5. Facing off Closed End of Shell to Length]


=Rough-turning Operations on Shrapnel Forging.=--Practically every type
of engine lathe and turret lathe as well as special machines are used
for turning and boring shrapnel forgings, and in the following chapter
each method will be dealt with separately. Before doing this, however,
a complete summary of the methods of machining employed in a large
plant turning out shrapnel will be described. In this plant, the first
rough-turning operation is handled on a flat turret lathe, as shown in
Fig. 6. For this purpose, the shell forging is held on an expanding
arbor and is driven by a dog fastened to it and driven by the faceplate
of the lathe. A multiple tool turner is first brought into position and
takes a cut of about ¹⁄₈ inch from the diameter for practically the
entire length of the shell. The next tool then faces off the end of the
shell to length.

[Illustration: Fig. 6. First Rough-turning Operation on Shrapnel Shell
in a Flat Turret Lathe]

The shell forging is now ready for cutting the rifling band groove
and producing the waves. This is handled in an ordinary engine lathe
equipped with a special fixture, carrying grooving, waving and
under-cutting tools. The shell forging, as shown in Fig. 7, is held in
a chuck at one end and supported by a revolving center at the other.
One part of the fixture is clamped to the bed of the lathe and the
other to the carriage. The grooving and ribbing is accomplished with
a tool held in holder _A_ at the front of the lathe, whereas the two
under-cutting tools are held in holders _D_ and _E_ at the rear of
the lathe. In operation the carriage of the lathe is moved toward the
chuck, carrying the fixture to which are fastened cams _C_, _F_, and
_G_. Cam _C_ forces in the holder carrying the combination grooving and
ribbing tool, whereas cams _F_ and _G_ force in the holders carrying
the two under-cutting tools, these being presented at an angle to the
work. The required oscillations to the slide carrying the grooving and
ribbing tool are secured through a face-cam _B_ clamped to a “Whiton”
chuck. The face-cam operates against the tension of spring _H_ and
gives the required oscillations to the tool-slide carrying the ribbing
and grooving tool, shown at _A_.

The third machining operation is accomplished in a flat turret lathe,
as illustrated in Fig. 8. This consists in facing the open end of the
shell, boring the powder pocket and facing and boring the diaphragm
seat, and also turning the angular surface on the external nose of the
shell. First, a roughing drill is brought in to rough out the powder
pocket. The turret is then indexed and a tool for turning the angle
of the nose is brought into position. The machining on the nose is
then accomplished by operating the cross-sliding head. Then a roughing
cutter is brought in to rough-bore the powder pocket. The turret is
again indexed and a finishing tool is brought in to finish the powder
pocket and face the diaphragm seat. This finishes the machining
operations on the shell previous to heat-treatment.

[Illustration: Fig. 7. Cutting the Rifling Band Groove with a Special
Grooving and Ribbing Attachment on an Engine Lathe]

[Illustration: Fig. 8. Third Machining Operation on Shrapnel Shell in
a Flat Turret Lathe, consisting in Facing the Open End of the Shell,
Boring the Powder Pocket, Facing and Boring the Diaphragm Seat, and
Turning the Angular Surface on the External Nose of the Shell]

[Illustration: Fig. 9. Heat-treating Shrapnel Shells, using a Hoskins
Electric Barium-chloride Bath Furnace]

[Illustration: Fig. 10. Testing Hardness of Shrapnel Shells with Shore
Scleroscope]


=Heat-treating Shrapnel Shells.=--As was previously stated, the tensile
strength of a forged shrapnel shell after heat-treatment must be from
80,000 to 90,000 pounds per square inch, and in order to obtain the
desired physical qualities, it is necessary that the heat-treating
operations be properly conducted. Several methods of heat-treating
employing different cooling solutions are used in the manufacturing
plants making shrapnel shells. One method, as shown in Fig. 9, is
to heat the shell in a Hoskins electric furnace that contains a
barium-chloride bath, heated to a temperature of about 1480 degrees F.
The shells are left in this furnace for half an hour and are taken out
and dipped in a bath of cottonseed oil heated to a temperature of 113
degrees F. The temperature to which the shell is heated varies with the
different constituents of the steel and practically every different
batch of 120 shells requires a slightly different temperature.
The proper temperature is determined by cutting out a section of a
heat-treated shell and testing it for tensile strength. The next step
is to draw the temper on the open end of the shell. In this operation
a muffle gas furnace heated to a temperature of about 1000 degrees F.,
is used. The temper is drawn for about two-thirds of the length of the
shrapnel shells.


=Testing for Hardness and Tensile Strength.=--One shell from a batch
of 120 is now cut open in the proximity of the powder pocket and the
cut-out section sent to the government inspectors to test it for
tensile strength. Each one of the shells in the batch, in addition, is
tested for hardness by a Shore scleroscope as shown in Fig. 10. Before
testing for hardness, the shell near the band groove is polished so
as to get a true reading, then placed in a fixture, and the hammer of
the scleroscope allowed to drop on it. The reading should be between
40 and 50, indicating an elastic limit of from 80,000 to 90,000 pounds
per square inch. The shell must not be ruptured at the point tested
when the charge in it is exploded or when the charge in the case is set
off. Should the shell upset near the rifling band groove when it is
propelled out of the gun, it would tear out the rifling in the bore of
the gun.

Experience with the scleroscope has disclosed the existence of a
fairly definite relation between the hardness and strength of metal.
In determining the strength of metal, two stages are recognized:
First, the elastic limit, determined by the load required to produce a
permanent set; second, the ultimate strength, determined by the load
required to cause rupture. The hardness indicated by the scleroscope is
intimately related to the elastic limit. The elastic limit increases
more rapidly than the hardness from 43 to 45, this being the minimum
index of the strength value required. As an elongation of 8 per cent in
2 inches is also required, there must necessarily be an upper limit to
the hardness. On the steel used for shrapnel, which is generally about
50-point carbon and 60-point manganese, the maximum hardness should not
be over 60 on the scleroscope.


=Tests relating to Heat-treatment of Shells.=--In the September, 1915,
number of MACHINERY, Mr. J. M. Wilson, who has been actively engaged in
heat-treating shells since the beginning of the war, and who has had
to rely entirely upon his own resources in meeting and overcoming the
troubles which seemed to arise on all sides, relates the results of his
experiments.

[Illustration: Fig. 11. Cross-sectional View of Shrapnel Shell showing
Points A, B, and C where Tests are made, and one of the Tensile Test
Samples]

The British government shell specifications call for a yield point
or elastic limit, after heat-treating, of not less than 36 tons per
square inch, a breaking point or ultimate strength not less than 56
tons per square inch, and an elongation not less than 8 per cent in
⁵⁄₈ inch. Officially there is no maximum specified for either of those
three physical characteristics; but as a matter of fact any unusual
condition which is not in conformity with recognized metallurgical
practice may cause the chief government inspector for the district in
which the manufacturer is located to reject a shipment. Reference has
been made to certain points in the shell which must resist the strains
due to firing. The nature of these strains and condition of the steel
best suited to meet them will be understood from Fig. 11, which shows a
cross-section of the British 18-pound shrapnel shell. When a shell is
fired from a gun, the base _A_ is subjected to a blow, _i.e._, a sudden
increase of pressure which almost instantly attains a maximum of from
12 to 14 tons per square inch, and imparts the initial velocity to the
shell. The shell, being a body at rest, opposes this velocity with its
own inertia, the result being that both compressive and tensile strains
are set up in the shell body. The shell body assumes the conditions of
a column which has a compressive load varying from nothing at the nose
to a maximum at the base. The tensile load is due to the inertia of the
bullets inside the shell. These bullets are subject to an increasing
compressive load from the top down, the resultant strain being a
bursting effort which attains a maximum in the region of the point _B_,
known as the “set-up point.”

When the time required for the fuse to act has elapsed, the powder
charge is exploded, and the contents of the shell are blown forward in
the usual manner. The contents are released either by the stripping of
the thread of the brass socket, or else the walls of the shell yield at
the point _C_, opening the threads sufficiently to free the socket. At
_A_, (the base) the shell must be perfectly sound and free from flaws
such as minute cracks, etc., which may allow the flame from the firing
charge to strike through with disastrous results to the shell and gun.
The metal in the base must not be too hard or it may fracture under
the pressure of the explosion, and it must not be too soft or it may
flatten out and spoil the rifling in the bore. At the point _B_ there
is no maximum requirement so far as tensile strength is concerned, but
any abnormal strength is viewed with suspicion unless it is accompanied
by a generous elongation. At _B_ the metal is particularly liable to
distension while the shell is acquiring velocity, and unless the shell
is strong enough to resist the sudden bursting strain, and the amount
of elongation is sufficient to cushion or absorb this strain at the
instant of firing, the shell is liable to take a permanent set in the
region of point _B_, with results mentioned above. The shell must not
be too hard at the point _C_ as it may burst, thus neutralizing the
real object of a shrapnel shell which is to project the bullets forward
with increased velocity at the predetermined instant, being in fact an
aerial gun arranged to discharge its contents at any desired point of
its flight.


=Uniformity of Steel for Shrapnel.=--Having these requirements firmly
established in his mind, the heat-treating expert is now confronted
with a double problem: How is it possible to give steel the suitable
strength; and having done so, how is it possible to know that the
desired result has been obtained, without actually making test pieces
from each shell. The principal condition upon which successful
heat-treating depends is uniformity of material. Carbon and manganese
are the principal substances which influence the results. The exact
composition of steel specified by the government is not given to
any manufacturers other than steelmakers. It is, however, generally
understood to be a 0.50 per cent carbon, 0.60 per cent manganese steel.
Allowing five points variation in carbon and ten points variation
in manganese, the requirements would be approximately 0.45 to 0.55
per cent carbon and 0.50 to 0.70 per cent manganese. In one carload
of forgings, one firm received shells from 23 different heats or
melts, with carbon varying from 0.60 to 0.47 per cent, and manganese
varying from 0.63 to 0.49 per cent, with all possible combinations
and proportions between these limits. The number of forgings supplied
from each heat varied from one up to 1200 so that the question of
determining the best temperature for each carbon content was indeed
quite impracticable. Many manufacturers at the present moment may be
in a similar position, and the gravity of the situation, both from a
financial and a military point of view, may justify a somewhat detailed
description of the method which was followed in treating shells of such
varying composition.


=Results of Tests.=--It is generally known to manufacturers that the
highest tensile strength of steel is obtained by cooling it rapidly
from a temperature slightly higher than the decalescent point or
critical temperature. The degree of hardness resulting from this
operation can be ascertained quickly, accurately, and repeatedly by
means of the scleroscope. The degree of hardness thus shown is a
reliable indication of the probable strength of the material; that is
to say, after making due allowance for different makes of steel and
varying proportions of the principal constituents, the scleroscope
readings are a reliable indication of the results which may be expected
when a tensile test is made of any given shell. In the opening months
of the shell business, considerable reliance was placed on the accurate
determination of the decalescence point. Forgings of varying analysis
were received; the carbon being from 0.48 to 0.53 per cent, and the
manganese from 0.54 to 0.69 per cent. All steels whose composition was
within those limits showed a decalescence point of between 1390 and
1425 degrees F., and when quenched in water at 50 degrees F. above
the decalescence point, such steels would have a scleroscope hardness
number as high as 85; but when quenched in ordinary fish oil the
hardness was only slightly over 50, the sample being 1 inch square and
¹⁄₈ inch thick. A complete shell quenched in fish oil would show a
scleroscope hardness number at the set-up point of from 38 to 40. Test
pieces from such a shell failed to reach the minimum breaking strength
of 56 tons by the narrow margin of 0.6 ton, and this failure brought
up the question of which was the best quenching medium. A series of
experiments gave the results presented in Table I; all conditions were
equal in each test, and the test pieces were all made from the same
forging.

TABLE I. RESULTS OF TESTS TO DETERMINE THE BEST QUENCHING MEDIUM FOR
SHRAPNEL SHELLS

  +-------------+----------------+--------------------+---------------+
  | Quenching   |   Quenching    |   Temperature of   |  Scleroscope  |
  |temperature, |    medium      |     quenching      |  hardness No. |
  | degrees F.  |                | medium, degrees F. |               |
  +-------------+----------------+--------------------+---------------+
  |    1475     | Fish oil       |         90         |   50 to 55    |
  |    1475     | Coal oil       |         90         |   65 to 70    |
  |    1475     | Cottonseed oil |         90         |   70 to 75    |
  |    1475     | Engine oil     |         90         |   75 to 80    |
  |    1475     | Oil of degras  |         90         |   77 to 85    |
  |    1475     | Water          |         90         |   82 to 87    |
  +-------------+----------------+--------------------+---------------+
                                                             _Machinery_

From the results of the tests presented in Table I, oil of degras,
commercially known as “No 2 soluble quenching oil,” was selected as the
quenching medium and operations were commenced on forgings supplied
from two separate heats. The results were all that could be desired
until forgings were received from a certain heat, which would not
respond to treatment based upon the results of preliminary experiments.
Investigation yielded the results presented in Table II. While
water-treatment of the forgings from “Heat No. 3” gave satisfactory
strengths under test, the liability of shells to crack, owing to
their thin walls contracting more rapidly than the base, was a fatal
objection to this method. Attention should be called to the fact that
while the temperature at which quenching should be done is specified by
the government at 1560 degrees F., manufacturers are not tied down to
this particular temperature. What is required is that the manufacturers
shall so treat the material that it will fulfill the requirements
already stated. If, when fulfilling these requirements, the treatment
should prove detrimental to the shell in other respects, then it must
be changed accordingly.

TABLE II. RESULTS OF TESTS CONDUCTED TO SECURE GENERAL DATA ON
HEAT-TREATMENT

  +------------------------------------+---------+---------+-----------+
  |              Heat No.              |    1    |    2    |     3     |
  +------------------------------------+---------+---------+-----------+
  |Carbon, per cent                    |  0.45   |  0.52   |   0.50    |
  |Manganese, per cent                 |  0.68   |  0.62   |   0.47    |
  |Decalescent point, degrees F        |  1400   |  1425   |   1390    |
  |Quenching temperature, degrees F    |  1450   |  1475   |   1450    |
  |Temperature of oil, degrees F       |   160   |   160   |    120    |
  |Resultant hardness, scleroscope No  |65 to 75 |65 to 75 |    *39    |
  |Temperature of water, degrees F     |         |         |     75    |
  |Resultant hardness, scleroscope No  |         |         | 55 to 60  |
  |Tempered until showing a scleroscope|         |         |           |
  |  hardness of                       |    48   |    48   |     52    |
  |Yield point, tons                   |  47.8   |  48.6   |   46.5    |
  |Breaking point, tons                |  67.9   |  65.4   |   66.2    |
  |Elongation, per cent                |  14.5   |  16.9   |   17.4    |
  +------------------------------------+---------+---------+-----------+
                                                             _Machinery_

* Note: This shell was then reheated and quenched in water with results
shown.

Referring to results presented in Table II, “Heat No. 3,” it will be
observed that the manganese is only 0.47 per cent with carbon 0.50 per
cent. Comparing “Heat No. 3” with “Heat No. 1”, it is evident that an
increase of 5 points carbon is more than offset by a reduction of 21
points in the manganese. Increase of temperature seemed to offer the
greatest possibilities and sample shells were drawn every 12¹⁄₂ degrees
up to 1675 degrees F. The greatest hardness was obtained at 1637¹⁄₂,
scleroscope readings of from 50 to 55 being the average. This was not
considered satisfactory, and the oil-circulating pump was speeded
up. Scleroscope readings as high as 65 were frequently obtained at a
quenching temperature of approximately 1635 degrees, and when the shell
was tempered to read 48 to 52 on the scleroscope, three test pieces
from one shell gave the results presented in Table III. A careful study
of this data revealed the fact that, while a low-carbon, low-manganese
steel hardens satisfactorily within a limited range of temperature, a
medium steel has a wider range, and a high-carbon steel, a still wider
range of hardening temperature.


TABLE III. RESULTS OF TESTS ON SAMPLES TAKEN FROM A SHELL WITH A
SCLEROSCOPE HARDNESS NUMBER OF FROM 48 TO 52

  +--------+---------------------+-------+---------+-----------+
  |Heat No.|Scleroscope reading  |Yield  |Breaking |Elongation,|
  |        |on test piece after  |Point, | point,  | per cent  |
  |        |     machining       | tons  |  tons   |           |
  +--------+---------------------+-------+---------+-----------+
  |        |Outside 52--53--50   |       |         |           |
  |   1    |Inside  55--55--55   | 55.8  | 73.3    |   14.3    |
  |        |                     |       |         |           |
  |        |Outside 52--54--50   |       |         |           |
  |   2    |Inside  55--57--53   | 53.8  | 72.4    |   17.4    |
  |        |                     |       |         |           |
  |        |Outside 57--57--49   |       |         |           |
  |   3    |Inside  60--62--51   | 52.8  | 77.3    |   12.7    |
  +--------+---------------------+-------+---------+-----------+
                                                     _Machinery_

When the shipment of mixed heats previously referred to was treated,
the method pursued was to take 0.50 per cent carbon and 0.50 per
cent manganese as a base composition which hardened at 1600 degrees
F. to show 55 to 65 hardness on the scleroscope. Then: (a) If, for
every point of carbon below 50, there be present 1 or more points of
manganese above 50, the steel should harden satisfactorily at 1600
degrees F. (b) If, for every point of manganese below 50, there be
present 2 or more points of carbon above 50, the steel should harden
satisfactorily at 1600 degrees F. (c) If both carbon and manganese be
below 0.50 per cent, increase the hardening temperature 12¹⁄₂ degrees
F. for each point of manganese short of 50, and 6¹⁄₄ degrees F. for
each point of carbon short of 50. (d) If both carbon and manganese
are above 0.50 per cent, a hardness number above 55 will probably be
obtained at a quenching temperature of 1600 degrees F., but the maximum
hardness, _i.e._, from 75 to 80, will be obtained at a somewhat lower
temperature, the exact temperature being most easily found by starting
at 1500 degrees F. and trying a couple of sample shells every 25
degrees F. until a maximum hardness is obtained. Forgings containing
from 0.50 to 0.55 per cent carbon and from 0.54 to 0.62 per cent
manganese in any varying proportions may be hardened at 1600 degrees
F. to show a hardness number of from 55 to 75; and when tempered to
give a hardness number of from 48 to 52 they will yield the following
results: yield point, 45 to 50 tons; breaking point, 65 to 70 tons; and
elongation, 14 to 20 per cent.

[Illustration: Fig. 12. Chart showing Hardening Temperatures for
Various Percentages of Carbon and Manganese in Steel used for Shrapnel
Shells]

Looking back, (c) offers a basis for charting the hardening points
in a fairly approximate manner, to form a guide as to where the
best hardness may be obtained. Such a chart is shown in Fig. 12.
By following the horizontal and vertical lines from the carbon and
manganese content until they intersect, a diagonal line will be found
which will indicate the temperature at or about which the maximum
hardness will be obtained. This does not prevent the use of 1600
degrees F. as the average temperature for the majority of shells,
provided they are strong enough when hardened at that temperature;
but where shells do not harden satisfactorily at 1600 degrees F., the
chart offers an alternative method subject to such variation as may
arise due to the use of steel from different makers, etc. Probably the
best practice is to make careful scleroscope readings of each piece
before pulling. Care must be taken to have a uniform surface on both
sides, all tool marks being removed with fine emery cloth. The points
tested are shown at _A_, _B_, and _C_ in Fig. 11. After the test piece
is made, the value of the hardness number increases as a result of the
piece being solidly supported in the scleroscope, whereas, when the
reading is made on the shell, the arched form of the wall acts as a
spring, and absorbs the shock to some extent. Readings thus increase
from 2 to 10 points after the test piece is finished.

TABLE IV. DATA ON THE HEAT-TREATMENT AND STRENGTH TESTS OF SHRAPNEL
SHELLS

  +--------+----------+------------+-----------+------------+-------+----------+-------------+
  |        |          | Quenching  | Tempered, |            |       |          |             |
  |Carbon, |Manganese,|temperature,|scleroscope|Readings of | Yield | Breaking | Elongation, |
  |  per   |   per    |  degrees   | hardness  |scleroscope | point,|  point,  |    per      |
  | cent   |  cent    |     F.     |    No.    |            | tons  |  tons    |    cent     |
  +--------+----------+------------+-----------+------------+-------+----------+-------------+
  | 0.50   |   0.47   |    1635    |     51    | 60-57-57   |  48.3 |   69.9   |    16.9     |
  |        |          |            |           | 47-48-48   |       |          |             |
  |        |          |            |           |            |       |          |             |
  | Three pieces from one shell    |           | 60-56-53   |  45.2 |   70.6   |    19.1     |
  |                                |           | 48-52-58   |       |          |             |
  |                                |           |            |       |          |             |
  |                                |           | 63-56-57   |  51.6 |   74.6   |    16.9     |
  |                                |           | 51-55-54   |       |          |             |
  |                                |           |            |       |          |             |
  | 0.48   |   0.65   |    1565    |     49    | 51-54-52   |  47.3 |   67.4   |    15.9     |
  |                                |           | 48-53-50   |       |          |             |
  |                                |           |            |       |          |             |
  | Three pieces from one shell    |           | 51-52-49   |  48.2 |   67.9   |    15.3     |
  |                                |           | 53-51-51   |       |          |             |
  |                                |           |            |       |          |             |
  |                                |           | 52-55-50   |  49.2 |   70.7   |    15.4     |
  |                                |           | 50-55-47   |       |          |             |
  |                   |            |           |            |       |          |             |
  | 0.50   |   0.57   |    1600    |     50    | 50-52-50   |  46.0 |   64.8   |    19.0     |
  |        |          |            |           | 49-50-49   |       |          |             |
  |        |          |            |           |            |       |          |             |
  | 0.50   |   0.57   |    1600    |     50    | 56-60-57   |  55.8 |   77.8   |    14.3     |
  |        |          |            |           | 54-56-54   |       |          |             |
  |        |          |            |           |            |       |          |             |
  | 0.50   |   0.57   |    1600    |     50    | 59-60-56   |  60.7 |   82.2   |    12.7     |
  |        |          |            |           | 55-59-56   |       |          |             |
  |        |          |            |           |            |       |          |             |
  | 0.60   |   0.57   |    1600    |     50    | 60-61-55   |  57.8 |   80.0   |    12.6     |
  |        |          |            |           | 60-62-57   |       |          |             |
  |        |          |            |           |            |       |          |             |
  | 0.60   |   0.57   |    1600    |     52    | 57-57-56   |  48.2 |   69.7   |    17.5     |
  |        |          |            |           | 54-56-53   |       |          |             |
  |        |          |            |           |            |       |          |             |
  | 0.50   |   0.57   |    1600    |     50    | 48-52-50   |  44.2 |   64.3   |    17.4     |
  |        |          |            |           | 49-52-49   |       |          |             |
  |        |          |            |           |            |       |          |             |
  | 0.50   |   0.57   |    1600    |     50    | 52-55-55   |  44.7 |   65.2   |    14.7     |
  |        |          |            |           | 60-51-52   |       |          |             |
  +--------+----------+------------+-----------+------------+-------+----------+-------------+
                                                                                 _Machinery_

A careful study of the data presented in Table IV reveals the
fact that results are not always consistent. With an increase of
carbon, one occasionally finds an increase in elongation and _vice
versa_; and the results due to variations in manganese content are
similarly unreliable. In order to secure a degree of uniformity in
hardness, which will be sufficient to insure test pieces standing up
successfully, it is necessary to have the shell hard inside as well as
outside, and a method of doing this is referred to later. Assuming now
that the shell has been tempered, it is rough-polished on a canvas
buffing wheel around the outside of _B_, Fig. 11, for a width of at
least 1 inch. Readings by the scleroscope are made on a zone ³⁄₄ inch
wide, and if they are between 46 and 52 the shell may be relied upon
to show good results in the tensile test. In making test pieces, it
is desirable to cut the piece from a spot which reads 48 to 50; and
in machining the test piece, care should be taken to remove an equal
quantity of metal from either side of the wall so that the test piece
is a true specimen of the average wall structure. Where a shell is
carelessly quenched, and the test piece so machined that the surface
on one side is practically the same as the inner side of the wall, the
results would not be a true indication of the real average strength,
and a lot of shells might possibly be rejected on account of a slight
oversight in this respect. Reference has been made to the base _A_,
Fig. 11. Forging defects show up here occasionally and in such cases
the shell is at once condemned. These flaws take the form of small
cracks, from the width of a hair up to ¹⁄₁₆ inch. They seldom can be
detected until after heat-treating, and are most easily observed by
polishing the base on a disk grinder. Losses in this respect vary, but
might average about 0.20 per cent. The hardness of the base itself may
vary from 38 to 50, which insures an ample degree of toughness and
avoids all possibility of the shell cracking under fire.

[Illustration: Fig. 13. Lay-out of Heat-treating Department for a
Factory Producing from 12,000 to 15,000 Shrapnel Shells a Week]


=Heat-treating Department.=--Many methods of heating, quenching,
annealing, and cleaning are in use by the different firms engaged in
shell making. For rapidity of output, cleanliness of the resulting
product, ease and economy of operation, and uniformity and control of
results, the lead bath seems best for hardening, and the semi-muffle
furnace for annealing. In one case the use of a lead bath by a skilled
operator yielded excellent results both as to economy and uniformity,
but, when the output exceeds 500 shells per 12 hours, a semi-continuous
furnace meets the requirements to better advantage. The lay-out of a
hardening room for an output of 12,000 shells per week is given in
Fig. 13. The lead baths consist of a rectangular pot of suitable
capacity, resting on a 4¹⁄₂ inch hearth built of common firebrick and
heated by either oil or gas burners below the hearth. They are built
in pairs with a common wall between, which is thick enough to provide
a flue to carry off products of combustion. The quenching tanks are
rectangular, water-jacketed, and provided with two quenching cradles
each. These cradles are arranged to swing lengthwise in the tank, and,
when the carrier holding the shell is lowered into the oil, a pipe is
automatically extended downward into the shell and introduces cold oil
in the inside of the shell, while the operator swings the cradle back
and forth in the tank, thus cooling the outside of the shell at the
same time. This method of quenching made it possible to harden shells
which, by reason of low carbon and manganese, defied all conventional
methods of dipping and swinging back and forth with tongs. The output
per man with this apparatus is largely in excess of any hand method,
while the uniformity and degree of hardness is all that could be
desired.

[Illustration: Fig. 14. Special Arrangement of Scleroscope for Testing
Shrapnel Shells]

[Illustration: Fig. 15. Closing-in Nose of Shrapnel Shell in Hydraulic
Press]

The oil pump draws the oil from a depth of 6 inches below the surface
and pumps it through 100 feet of 1-inch copper pipe arranged in two
50-foot coils in parallel. The cooled oil is delivered into an overhead
reservoir, the overflow being connected to both tanks equally. After
quenching, the shells are set on draining racks, and then washed in
boiling water and sal-soda, placed on another draining rack and then
brushed with wire brushes previous to tempering. The tempering furnace
is of rectangular form, and consists of a long flat hearth with rails
laid lengthwise on it. At each end a space is partitioned off from the
body of the furnace, by means of vertical sliding doors; and a rack
holding a number of shells is deposited on the rails at the front end
of the hearth, the door is elevated and the rack is slid into the main
chamber. After a suitable lapse of time another rack is introduced,
and so on until the first rack is ejected at the rear end of the
furnace. The shells are now hot enough to loosen all foreign matter on
the surface, and a few seconds brushing with a wire brush cleans out
the driving band groove, and leaves the shell with a delicate brown
oxidized finish. The shell is now spotted on three places with a canvas
buff and tested for hardness. Fig. 14 shows the arrangement of the
scleroscope. The shell is supported on a single narrow V-block with
hardened edges, situated immediately under the set-up point. A narrow
strip supports the open end of the shell, thus giving a three-point
support, while a vertical stop at the back of the shell maintains it
in a position tangential to the radius of the swinging arm. The usual
rubber bulb was soon dispensed with as being quite unsuited for such
hard service, and a small pump cylinder substituted. The piston in the
cylinder is operated by a downward pressure of the heel on the pedal to
give compression, and a spring inside the cylinder gives the necessary
pull when the scleroscope hammer is to be raised by suction. After
being tested the shells are ready for “nosing-in.”

[Illustration: Fig. 16. Third Operation on Nose of Shrapnel
Shell--Turning, Facing, and Threading]

[Illustration: Fig. 17. Grinding Shrapnel Shells in One Operation in a
Ford-Smith Grinding Machine carrying a Wheel about 8¹⁄₄ Inches Wide by
20 Inches in Diameter, rotated at 1200 Revolutions per Minute]

[Illustration: Fig. 18. Closing-in Copper Band on Shrapnel Shell in a
Machine provided with Six Dies, as shown in Fig. 20, back of each one
of which there is a Hydraulic Cylinder]

=Closing-in the End of the Shell.=--On some makes of shells,
particularly the British, the nose is closed in before performing the
third series of machining operations. The closing-in is generally
accomplished in a hydraulic or power press. Fig. 15 shows the
closing-in operation being performed in a vertical hydraulic press
capable of exerting a pressure of 800 pounds per square inch. Before
closing the open end of the shell, it is heated in the lead bath, shown
to the left of the illustration, which is kept at a temperature between
1450 and 1500 degrees F. The steel diaphragm, which is larger in
diameter than the nose of the shell, is first thrown in. Then the shell
is placed in the press, and a cone-shaped die descends, closing-in the
nose to the proper shape and diameter. The third machining operation
consists in finishing the radius on the nose, both inside and outside,
and cutting the thread. This is done, as shown in Fig. 16, in an
ordinary engine lathe with a turret on the saddle. The boring is done
with cutters held in boring-bars and the thread cut with a Geometric
collapsible tap. The thread on the 18-pounder is 2.94 inches in
diameter, 14-pitch, Whitworth type.

[Illustration: Fig. 19. Special Type of Wheel-truing Device used on
Ford-Smith Grinding Machine shown in Fig. 17]


=Grinding Shrapnel Shells.=--The exterior surface of a shrapnel shell
is straight for a portion of the length and then curved on the nose.
While the limits required are not extremely close, it is necessary,
where large production is required, to accomplish the finishing
operations on the exterior of the shell in some way by which fairly
close dimensions can be secured as well as large production. Grinding
has, therefore, been recommended for finishing the exterior of the
shell. One method of grinding shrapnel shells, in which a wide-faced
wheel is used that covers the entire ground surface, is shown in Fig.
17. This machine is built by the Ford-Smith Machine Co., Hamilton,
Ont., and carries a wheel about 8¹⁄₄ inches wide by 20 inches in
diameter. The grinding wheel is rotated at 1200 R. P. M., and the work
at 50 R. P. M. The depth of the cut is about ¹⁄₃₂ inch, and the time to
complete one shell varies between two and three minutes. For grinding,
a plug is screwed into the open end of the shell. This is held on the
tailstock center and a chuck holds and drives the shell from the other
end.

[Illustration: Fig. 20. Close View showing Closing-in Dies of Banding
Machine shown in Fig. 18]

It is necessary, of course, that the wheel be kept the correct shape,
and for this purpose an interesting type of wheel-truing device,
differing considerably from that shown in Fig. 17, is now used.
Referring to Fig. 19, it will be seen that this comprises a combination
wheel guard and bracket, the latter being used as a base for the
wheel-truing device proper. The diamond _A_ is carried in a holder _B_
that operates in a slide in the face of the traversing wheel-truing
slide _C_. The diamond holder carries a cam point _D_ which is kept in
contact with the guide or former cam _E_ by means of a spring _F_. The
wheel-truing slide _C_ is traversed by a triple pitch screw _G_ so as
to give a rapid movement to the slide in order to produce what might be
termed a “rough-truing” of the wheel. For change in diameter, and also
for bringing the diamond in contact with the wheel, a vertical slide
_H_ is provided that is operated by handle _I_. In order to observe the
diamond when truing the wheel, a trap door _J_ is provided in the wheel
guard, which can be dropped down into place when the actual grinding of
the shell is being done.


=Pressing on the Rifling Band.=--In order to rotate the shrapnel when
propelling it out of the howitzer, it is necessary to put on a rifling
band to take the rifling grooves of the gun bore. As a rule, these
rifling bands are made from copper tubing and are simply cut off in a
hand screw machine or turret lathe. The next operation is to close in
the rifling band on the shrapnel shell. The ring is dropped over the
shell and a fixture is used to locate it in the correct relation to
the groove in the circumference of the shell. Then a slight pressure
is exerted on it to align it properly in the groove. It is now placed
in the banding machine shown in Fig. 18. This particular machine is
provided with six dies as shown in Fig. 20, and back of each one is
a hydraulic cylinder operated by water pressure. Two squeezers are
necessary to close the rifling band properly into the groove, the shell
being given a half turn after each squeeze.

[Illustration: Fig. 21. Shrapnel Banding Machine built by the West Tire
Setter Co., having a Capacity for Compressing two Bands per Minute]

There are several different machines on the market for performing this
closing-in operation on the rifling band. Another machine, built by
the West Tire Setter Co., Rochester, N. Y., is shown in Fig. 21. The
principle upon which this machine operates is almost identical with
that previously described, but in this case oil is used as a pressure
medium. It is forced into the machine by means of a belt-driven pump
shown to the left of the illustration, which drives the oil from the
oil tank and carries it to the center of the base of the press. An
oil head is located at this point from which the pipes are run to
each of the six rams or cylinders. The amount of pressure required
for compressing the copper band depends largely upon the width and
thickness and the amount that the band must be spread to fill the
grooves, rather than upon the diameter of the shell. The machine
shown in Fig. 21 is capable of exerting a pressure of 30 tons on each
cylinder or a combined pressure of 180 tons on all six cylinders. It
has a capacity for compressing at least two bands per minute.

[Illustration: Fig. 22. Assembling Bullets, Resin, and Fuse Socket in
Shrapnel Shell]

[Illustration: Fig. 23. Finishing Rifling Band on Shrapnel Shell to
Shape]


=Machining the Rifling Band.=--One method of machining the rifling band
to the correct shape is shown in Fig. 23. Here a Fox lathe is used
which is provided with a chuck for holding the shell and which carries
in the turret a revolving center for additionally supporting it. The
machining is done by form tools which are of the correct shape. Before
any other machining operations can be accomplished it is necessary
to put in the tin powder cup, brass fuse tube, bullets, and resin.
This cup is slipped in past the steel diaphragm, then both parts are
allowed to drop to the bottom and the fuse tube is screwed into the
diaphragm. The required number of lead bullets, which for the British
18-pound shrapnel is about 375 per shell, is then poured in. The
bullets are held in a tank and are allowed to flow out upon the opening
of a stopcock. In order to pack the bullets solidly, a compressed air
ramming device forms the base upon which the shell rests while the
bullets are being poured in. This is operated three or four times for
the filling of each shell and arranges the bullets compactly.

[Illustration: Fig. 24. Illustration showing some of the Principal
Gaging Operations on Shrapnel Shells]

[Illustration: Fig. 25. 18-pound Shrapnel Shell showing Dimensions and
Manufacturing Limits]

The resin is now poured in, as shown in the center of Fig. 22. This
is carried in the tank which is heated by a gas furnace and is poured
in almost level with the top of the bullets. The shell is then placed
on the scale in the immediate foreground and weighed. One dram plus
or minus is allowed as a variation, and in order to not exceed this,
more or less resin is poured in until the correct weight is obtained.
The brass fuse socket is now screwed in as shown to the left of the
illustration, and upon the completion of this operation the shell is
ready for the fourth and last machining operation. This last operation
consists in machining the brass socket on the outside diameter to
conform to the radius on the nose of the shell, and boring on the
inside and threading to fit the fuse body. These operations are handled
in a Fox brass working lathe. Upon the completion of the machining
operations the plug is screwed in, the shell stamped, cleaned, weighed,
and inspected by government inspectors. After this, the shell is given
two coats of paint and a red band is painted around the nose. It is now
packed in boxes holding six shells and is ready for shipment. This
completes the manufacture of the shrapnel shell.

[Illustration: Fig. 26. Group of Gages made by Wells Bros. Co. for
gaging British Shrapnel Shells and Parts]

[Illustration: Fig. 27. Diagram showing Application of Wells Bros.
Gages]


=Gaging Shrapnel Shells.=--The machining operations on shrapnel
shells are required to be held within certain limits, and government
inspectors watch these closely. Some of the principal gaging operations
on the shrapnel shell body are shown in Fig. 24. Fig. 25 shows the
18-pound shrapnel shell in section, and gives the principal dimensions
together with the limits; it will be seen from this illustration that
the range allowable is in most cases large. The Wells Bros. Co.,
Greenfield, Mass., has made a large number of shrapnel gages, some of
which are shown in the accompanying illustrations. In the three upper
views of Fig. 24, the Wells Bros, standard thread gage is illustrated.
This is used for all diameter measurements by substituting flat gaging
pins for the V-points used when gaging thread diameters.

[Illustration: Fig. 28. Collection of Wells Bros. Co.’s American
Shrapnel Shell Gages]

[Illustration: Fig. 29. Dwight-Slate Hand-operated Marking Machine for
Shrapnel Shells]


=Gages for British Shrapnel Parts.=--Fig. 26 illustrates typical gages
for gaging such parts of the British shrapnel as body diameters,
diaphragm seat, powder pocket, fuse socket, thread diameters, and fuse
parts. Fig. 27 shows the application of several different types of
shrapnel shell gages. At _A_ is the gage for the over-all length. At
_B_ is the gage used for measuring the thickness of the closed end.
The outer arm of this gage can be swung away to allow the placing of
the gage on the standard. At the extreme lower left-hand corner of the
gaging arm is a slight shoulder on the rod and the height of this acts
as the limit. _C_ shows the application of outside diameter and thread
gages. _D_ shows three form gages for checking the shape and dimensions
of the wave ribs, the diameter and shape of the undercut in the band
groove, and the shape of the nose of the shell. _E_ shows the gage
used for checking the thickness of the wall of the shell at different
distances from the mouth. _F_ shows the application of a powder pocket
gage, and also a gage for checking the shape of the finished rifling
band.

[Illustration: Fig. 30. Power-driven Dwight-Slate Marking Machine for
Shrapnel Shells]


=Gages for American Shrapnel Shells.=--Fig. 28 shows a miscellaneous
collection of gages used in checking the dimensions of the American
shrapnel shell. Gages, _A_, _B_, _C_, and _D_ are for measuring the
diameter of the diaphragm seat. _E_ is for checking the distance from
the diaphragm seat to the mouth end of the shell, and gage _F_ is for
the outside diameter of the shell. Gage _G_ is used for the rifling
band groove. Gages _H_ and _I_ are for the thread in the mouth of the
shell, _H_ being a “not-go” and _I_ a “go” gage.

The gage at _J_ performs several gaging functions on the American
shell. It consists of a standard having two upright posts across which
a bar is mounted. The purpose of the bar is to gage the over-all
length of the shell, and its lower surface is provided with two steps
giving the limits. This gage is also used for measuring the depth of
the powder pocket, rod _K_ and block _L_ performing this function. Two
rings are cut around the rod _K_ registering with the top surface of
the bar, the purpose being to show the accuracy of the work.

Another interesting gage is shown at _M_. This is for gaging the
concentricity of the shell and consists of an arbor mounted so that it
can be swung on a pivot. The arbor carries two collars _N_ and _O_ that
fit in the shell. Collar _P_ is merely a sizing plug and when the gage
is in use this plug is removed. A gaging finger _Q_ rests against the
shell when it is on this arbor, and a standard type of indicator _R_
shows the variation in concentricity when the gage, collars, and shell
are rotated on the arbor.


=Marking Shrapnel Shells.=--All shrapnel shells are marked on their
circumference with five or six lines of lettering, as shown in Fig. 29.
This indicates the size of the shell, the series, muzzle velocity, name
of the manufacturer, date completed, etc. Two types of machines for
producing the stamping, built by Noble & Westbrook, Hartford, Conn.,
are shown in Figs. 29 and 30. The machine shown in Fig. 29 is of the
hand-operated type. The figure block _A_ is held in a slide that is
moved longitudinally by pulling down handle _B_, rolling the shell, and
at the same time stamping it. The shell is located on the table in the
two positions by gages _C_ and _D_.

The “Dwight-Slate” stamping machine shown in Fig. 30 is power-driven,
and the work is held on an elevating table. The stamp is held in a
slide operated by an eccentric and connecting-rod. In this machine the
shell is not distorted.




CHAPTER IV

MACHINES AND TOOLS FOR SHRAPNEL MANUFACTURE


=Reed-Prentice Co. Equipment for Machining Forged Shrapnel Shells.=--In
machining the 18-pound British shrapnel shell on the equipment
furnished by the Reed-Prentice Co., Worcester, Mass., eight distinct
operations are performed as follows: First, drilling a center hole
in the closed end of the forging in a Prentice 16-inch ball-bearing
sensitive drilling machine equipped with a special centering fixture;
second, rough-turning the outside diameter, grooving, squaring the
closed end and rounding the corners in a Reed-Prentice 14-inch heavy
type automatic lathe; third, machining the powder pocket and diaphragm
seat, as well as the internal and external diameters of the nose in
a 14-inch Reed extra-heavy turret lathe; fourth, under-cutting band
grooves and producing wave ribs in a 14-inch Reed engine lathe; fifth,
boring, reaming, threading and facing the open end in a Reed 14-inch
extra-heavy turret lathe; sixth, finish-turning outside diameter and
radius on nose, also form-turning copper band in a Reed 14-inch heavy
type automatic lathe; seventh, cutting off center projection on closed
end of shell in a Reed 14-inch engine lathe; eighth, finishing brass
socket to form, cleaning inside of socket and cutting off excess length
of tube in a Reed 14-inch extra-heavy turning lathe.


=First Operation on Rough Shell Forging.=--The drilling of the center
hole in the closed end of the forging is a comparatively simple
operation, and is performed in an interesting fixture held on a 16-inch
Prentice ball-bearing sensitive drilling machine. This fixture, which
is designed for handling the work quickly, is shown in Fig. 1, and
consists of the base casting _A_ clamped to the table of the drilling
machine. The entire back part of the jig swings on the trunnion _B_ to
provide a means for quickly removing the forging _C_ from the arbor
_D_. A locking-pin _E_ is used for locating the fixture in its upright
position for drilling. Bushing _G_ in the top plate _F_ of the fixture
guides the combination drill and countersink.

[Illustration: Fig. 1. Fixtures used for holding Shrapnel Shell
Forgings when drilling Center Hole in a 16-inch Prentice Ball Bearing
Sensitive Drilling Machine]

The construction of the work-holding arbor is worthy of special
attention. This arbor _D_ has a cap _H_ on its top end that acts as a
stop for the inside of the forging, which, in being placed over the
arbor, is located centrally and clamped by fingers _N_. To operate
these fingers, hand lever _I_ is depressed, and as this is fulcrumed
at the point _J_, it causes collar _K_ to rise on the arbor. Yoke _L_
forms a connection between the lever and the collar with which the
sleeve carrying fingers _N_ is integral. Fingers _N_ are fulcrumed in
arbor _D_ and are thrown outward to grip the forging when sleeve _M_
is raised. Light springs _O_ tend to keep the gripping fingers in a
vertical position against the arbor when they are not being forced
outward by the inclined surfaces on sleeve _M_. Handle _I_ carries a
spring pawl _P_ that holds the sleeve _M_ stationary while the forging
is being center-drilled.

[Illustration: Fig. 2. Tool Lay-out for performing Second Series of
Operations on Reed-Prentice Heavy Type Automatic Lathe]


=Second or Rough-turning and Facing Operations.=--The second operation
is performed on a Reed-Prentice 14-inch heavy type automatic lathe,
as shown in Figs. 2 and 3. The forging _A_ is held on an internal
expanding arbor _B_, the driving part of which is supported by
the head-center. At the closed end, the shell is steadied by the
tail-center. The bottom of the shell rests against the end of the
arbor which acts as a gage. In this setting, the external diameter of
the forging is rough-turned by four tools _F_, mounted on the carriage
_G_. This carriage has a travel slightly less than two inches, and an
automatic throw-off is provided at the end of the cut that disengages
the tools, draws them back and returns the carriage. At the rear of
the carriage on this machine a facing arm is mounted on a heavy bar.
Turning tools are carried on this facing arm, as shown, and when the
front carriage feeds longitudinally a cam bracket _O_, bolted to the
carriage, is carried along with it. Clamped on this bracket is an
adjustable cam _N_ held in place by screws. Cam roll _M_ on the facing
arm contacts with cam _N_, causing the facing arm to rock forward as
the carriage travels longitudinally.

[Illustration: Fig. 3. Section through Reed-Prentice Automatic Lathe,
showing Tool Arrangement]

Referring to the plan view in Fig. 2, tool _H_, held in the arm, faces
the end of the forging, tool _I_ chamfers the corner, and tool _J_ cuts
the depression for the wave ribs, leaving a projection in the center
from which the ribs are formed. It should be understood that the tools
on the carriage and facing arm work together. One man can run two of
these machines without trouble.


=Third Series of Machining Operations.=--The third series of operations
on the shrapnel forging is performed on a 14-inch Reed heavy lathe with
a specially large turret, as shown in Fig. 4. This lathe is fitted
with a 12-inch three-jaw chuck, bored out to 3¹⁄₂ inches to permit
the forging to extend into it. The forging _A_ is put in the chuck
as shown at _B_, and the jaws grip at _C_. The first operation is
performed with a bar _D_ carrying a blade cutter _E_ that rough-bores
the powder pocket, and tool _F_ that rough-bores the mouth. The turret
is now indexed, and a boring-bar carrying a blade _G_ roughs out the
diaphragm seat, while an auxiliary tool _H_ faces the shell to length.
At the next indexing of the turret the boring-bar _I_ that carries the
finishing tool _J_ finishes the diaphragm seat and powder chamber.

[Illustration: Fig. 4. Tooling Equipment for performing Third Series of
Operations on 14-inch Extra-heavy Turret Lathe]

[Illustration: Fig. 5. Tools used for Under-cutting and Waving Band
Grooves on Reed 14-inch Engine Lathe]


=Fourth Operation--Under-cutting and “Waving” Band Groove.=--For the
fourth operation, the forging is held in a 14-inch Reed engine lathe
provided with an automatic attachment for under-cutting and waving the
ribs for the copper band. The tool equipment used is shown in Fig. 5,
where _A_ is the forging held by one end in the chuck and supported
on the opposite end by the tail-center. The tools are all located in
holders on the heavy base block _B_, and their operation is controlled
from the carriage _R_ of the lathe. The cutting of the wave ribs is
done by tool _C_ at the front, held on a slide that operates on the
top of block _B_. Spring _D_ keeps the roll _E_ on the lower slide of
the tool-holder in contact with the cam slot in cam-plate _F_ that is
fastened to carriage _R_. When the carriage is traversed toward the
chuck, the irregular surface of cam-plate _F_ engages the roll and
forces the tool-holder forward. Side motion to produce the wave is then
effected by face-cam _G_, mounted on the chuck and contacting with the
roll _H_. This roll is supported on a bracket forming an auxiliary
slide _S_ that carries the waving tool _C_. A stiff barrel spring keeps
slide _S_ in contact with the cam _G_. Thus, when the machine spindle
revolves, the auxiliary slide is caused to oscillate back and forth far
enough to give the desired amount of wave.

The under-cutting in the band groove is accomplished by tools _I_ and
_J_ which are mounted on separate tool-slides _K_ and _L_. These slides
are fed in at an angle to the axis of the forging, against the action
of coil springs _M_ and _N_, by the cam surfaces of plate _Q_ in which
rolls _O_ and _P_ work. Plate _Q_ is bolted to carriage _R_ which, in
advancing toward the chuck, forces in the under-cutting tools in the
manner just described. The tail-center of this machine is fitted with a
quick-acting mechanism so that it may be withdrawn quickly to insert a
new piece.


=Fifth Series of Operations.=--Before performing the fifth series of
operations, the forging is heated and closed in on the nose. It is then
handled in the following manner: A Reed 14-inch heavy lathe, equipped
with an extra large turret mounted on a special wide-bridge carriage
carries tools for boring, reaming, threading and final squaring of the
open end, as shown in Fig. 6. The shell forging for these operations
is held in a three-jaw chuck provided with special jaws. In the first
position the rough-boring of the nose and the rough-facing of the
extreme end is performed with tools _B_ and _C_. The turret is then
indexed and tools _D_ and _E_ finish-ream the hole in the nose and face
the end. The tap _F_ is next brought into position, cutting the thread
in the nose.

[Illustration: Fig. 6. Turret Tools held on Reed 14-inch Extra-heavy
Lathe for performing Fifth Series of Operations]

The turret is again indexed, bringing a special form boring tool into
position. Here the boring tool _G_ is carried in a bar _H_ held in a
holder of the cross-sliding carriage type that is fastened to two faces
of the turret. By means of cross-screw _J_, the boring tool _H_ may be
drawn in or out at will. This tool operates as follows: As the turret
is advanced, handle _J_ is operated to let tool _G_ enter the nose of
the shell, and, upon the continued advance of the turret, arrow head
_M_ is forced in between and gripped by the fingers _N_. The turret is
now backed away from the chuck, and while receding acts upon slide _P_
through the medium of roll _L_ and cam groove _R_. The plate containing
cam groove _R_ is attached to the arrow head _M_ and consequently is
held stationary while the turret is being withdrawn from the work. This
backward movement of the turret is continued until the tool _G_ is
withdrawn from the work and slide _S_ comes in contact with check-nuts
on rod _O_, withdrawing arrow head _M_ from fingers _N_ and allowing
the turret to be indexed ready for the first operation on the next
forging.

[Illustration: Fig. 7. Reed-Prentice 14-inch Heavy Type Automatic Lathe
used for performing Sixth Series of Operations]


=Sixth or Finish-turning Operations.=--The sixth series of operations
is performed on a Reed-Prentice 14-inch heavy type automatic lathe,
similar to that used for the second operation, and the machine is
also operated in a manner similar to that previously described. The
operations consist in finish-turning the outside diameter of the shell
and turning the radius on the nose. In addition, the copper rifling
band, put on previous to this operation, is turned to shape. Referring
to Fig. 7, the shrapnel shell _A_ is held by the tail-center at one end
and is supported and driven from the other end by a plug screwed into
it. This plug is held on the live center and is driven by an equalizing
driver, coming in contact with pins in the special faceplate.

[Illustration: Fig. 8. Tools for machining Brass Fuse Socket on 14-inch
Heavy Turning Lathe--Eighth Operation]

Two slides _B_ and _C_ are carried on the front of the carriage. Slide
_C_ carries three tools _D_; two of these start in from the rifling
band and turn in toward the nose, and the other works up toward the
rifling band from the closed end. Tool _E_, carried in slide _B_,
turns the curve on the nose of the shell and is controlled in its
action by means of a slot in cam _F_ in which a roller held to the
slide operates. At the rear of the carriage is carried a facing bar
attachment, as previously described in connection with the second
operation. This attachment carries three tools, as illustrated,
for machining the rifling band to shape, facing the closed end and
chamfering the corner.


=Seventh and Eighth Operations.=--After the sixth operation, the fuse
tube is threaded into the diaphragm, the bullets put in, and the hot
resin poured in to keep them from rattling. The brass socket is then
screwed into the nose and the fuse tube soldered to it. The shell is
now ready for the seventh operation which consists in cutting off the
center projection. This is accomplished in a Reed 14-inch engine lathe,
provided with a faceplate chuck for holding and driving the shell at
the open end, and a steadyrest for supporting it close to the point
where the cutting is being done. The shell is now ready for the eighth
operation, which consists in machining the brass socket to shape in an
extra-heavy lathe as shown in Fig. 8. The tools used for machining are
retained in a special holder on the carriage. Tool _A_, which is used
for facing off the fuse tube and the brass socket, is inverted, starts
at the center and is fed out toward the circumference. The external
surface of the socket is machined with a circular forming tool _C_ held
on a stud _D_ located in block _B_. The inward travel of this tool is
limited by stop _E_ coming in contact with the shell.

[Illustration: Fig. 9. Shrapnel Case made from Chrome-nickel Steel
having High Tensile Strength on a Cleveland Automatic Screw Machine
with Special Tool Equipment]

[Illustration: Fig. 10. Order of Operations on the Shrapnel Case]


=Making Shrapnel Shells on the Cleveland Automatic.=--An unusual
example of automatic machine work is that of producing the shrapnel
shell shown in Fig. 9. This shell is made from a bar of 3¹⁄₁₆ inch
chrome-nickel steel stock. The steel has a tensile strength varying
from 125,000 to 135,000 pounds per square inch, and is extremely tough.
The work is accomplished on a 3¹⁄₄-inch Cleveland automatic, and the
tooling equipment, as shown in Figs. 10, 11, and 12, is interesting.
While the general operation of the Cleveland automatic is well
understood by many mechanics, the production of this piece illustrates
a number of points in the operation of this machine which are not so
well known. Therefore, it is advisable to explain in detail just how
this interesting job is handled.

[Illustration: Fig. 11. Cleveland 3¹⁄₄-inch Automatic Screw Machine set
up for making a Shrapnel Case in Twenty-five Minutes]

The first operation, as the job was originally laid out, was to feed
the stock out to the stop _A_, shown in Fig. 11, which is held on the
cross-slide and operated by a lever on the base of the machine. This
method has been improved upon since the photograph shown in Fig. 11
was taken, and the time reduced from twenty-seven and one-half minutes
to twenty-five minutes (see Fig. 10 for improved method). The second
operation is to rough-drill the large hole with an inserted bit _B_,
step the hole for the taper reamer with cutter _C_ and rough-turn the
external diameter with cutter _D_ held in a special turning attachment.
This attachment envelops the shanks of all six tools in the turret in
order to obtain support. The cutters in the attachment shown in Fig.
11 work in advance of the under-cutting forming tool _E_ shown in Fig.
12, which is held on the rear cross-slide. The time required for the
completion of the operations outlined is thirteen minutes.

[Illustration: Fig. 12. Showing Tools held on the Front and Rear
Cross-slides for performing the Knurling, Forming, and Cutting-off
Operations on the Shrapnel Case]

In the third operation drill _H_ finishes the powder pocket, and two
cutters _I_ counterbore for the tap--time required three minutes. The
fourth operation consists in finishing the diaphragm seat with the
counterbore _J_, finishing the front end with inserted cutter _K_ and
breaking the corner to facilitate tapping with inserted cutter _L_,
the time required being forty-five seconds. In the fifth operation the
thread is cut with a tap _M_ held in the tap-holder _N_ in forty-five
seconds. Then the turret is indexed and for the sixth operation the
hole is taper-reamed with reamer _O_, provided with four inserted
“Novo” steel blades, in ninety seconds. The last and seventh operation
consists in knurling the band with a knurl _P_ (see Fig. 12) mounted on
the front cross-slide, and cutting off the shell with a cut-off blade
_Q_ retained in a holder on the rear cross-slide--time six minutes.
The total time required to produce this shrapnel case by the improved
methods illustrated by the diagram in Fig. 10 is twenty-five minutes.

There are several points of unusual interest in the production of this
shrapnel case. One is the large amount of stock to be removed to form
the hole; the second is the long taper-reaming operation--difficult
work to accomplish satisfactorily on an automatic screw machine--and
the third is the long outside forming operation which must be held to a
limit of 0.0005 inch on the diameter. In order to accomplish this last
operation successfully, the external diameter of the piece is first
turned with a cutter held in a separate turning attachment, leaving
only 0.010 inch on the diameter to be removed by a wide under-cutting
or shaving tool _E_ held very rigidly on the rear cross-slide. Not
only must the case be exact as regards diameter, but it must not vary
from one end to the other nor at any point throughout its length. The
large shaving tool held rigidly in the manner illustrated in Fig. 12
accomplishes this result satisfactorily.

The material from which the case is made is so tough that some
difficulty was met with in selecting a tool steel that would stand up
for a reasonable length of time under cut. The drills and counterbores
are tipped with “Novo” cutters and all the forming tools, including
the cut-off tool, are also made from the same steel. The only cutting
tool in the entire tooling equipment not made of this steel is the
tap. The bar is rotated at sixty-four revolutions per minute, giving a
surface speed for the external cutting tools of approximately fifty-one
surface feet per minute.

[Illustration: Fig. 13. First Operation on Shrapnel Shell, performed on
a No. 6A Potter & Johnston Automatic Chucking and Turning Machine]


=Machining the British Forged Shell on Potter & Johnston
Automatics.=--In making the British forged shell on the Potter &
Johnston automatic chucking and turning machine, three operations
complete the work. The first operation completes the outside of the
shell, except for the extreme end which is covered by the gripping
mechanism of the chuck. The second operation finishes the inside of the
shell and at the same time finish-turns the extreme open end. After
the second operation is performed the shell is “nosed,” which consists
in heating it in a lead bath and then striking it under a light press
to close in the end. The third operation then follows, and consists in
taking light cuts from the inside diameter and threading the open end
of the shell.

[Illustration: Fig. 14. Expanding Arbor and Chucking Mechanism used
on Potter & Johnston Automatic Chucking and Turning Machines for
performing First Operation on Forged Shrapnel Shells]

[Illustration: Fig. 15. Set-up on a No. 6A Potter & Johnston Automatic
Chucking and Turning Machine for First Operation on Forged Shrapnel
Shells]


=Method of Holding Shell for First Operation.=--For the first
operation, the shell is held on an expanding arbor of the type shown in
Fig. 14. The arbor _A_ is tapered on its rear end and is held in the
nose of the spindle of the machine. The shell is pushed onto this
arbor until the end of the arbor strikes the bottom of the shell. The
gripping mechanism which comprises six jaws _B_ and a draw-in plunger
_C_ is contained inside the arbor. The external diameter of the arbor
is machined to practically the same shape as the internal diameter of
the shell, but is smaller. The jaws are held in slots which control
their movement in every direction except radially. They are forced out
radially by means of the draw-in bar _C_ which is provided with tapered
seats that engage the inward end of the jaws. The bar _C_ is operated
by a hand lever _D_ that extends up over the top of the machine, is
fulcrumed in a bracket on the rear bearing cap, and is connected to a
sliding sleeve _E_.

In clamping the work on the arbor, lever _D_ is lifted up, this action
drawing the sliding collar _E_ to the right along the sleeve _F_,
which, in turn, allows the forward end of the fingers _G_ to close
in. This releases the pressure of the outer end of the fingers on the
draw-in bar _C_. When the pressure from bar _C_ is released by means of
handle _D_, heavy coil springs _H_ then come into action forcing the
draw-in bar back and expanding the clamping jaws. Additional clamping
means are provided by three set-screws which are brought to bear on the
work after it has been clamped in position by the jaws. To release the
work, the reverse action takes place, that is, lever _D_ is forced down
which slides the collar _E_ to the left, operating the fingers _G_,
which, in turn, overcome the pressure of the springs _H_, allowing the
clamping jaws _B_ to collapse.


=First Machining Operation Set-up.=--The order of the first series of
operations in machining a forged shrapnel shell is as follows: First,
rough-turn 7 inches along body of shell, face end and chamfer; second,
finish-turn 2¹⁄₂ inches along shell; third, rough-groove for copper
band and dovetail; fourth, turn waves in groove.

For the first operation, the work is held on the expanding arbor
shown in Fig. 14, and the tool equipment, which is of an unusually
interesting character, is shown in Fig. 15. The first rough-turning
operation, accomplished by turret tool _A_, which is of the relieving
type to be described later, is held on the first face of the turret and
roughs down the body of the shell. On the opposite side of the holder
is a roller support _B_ which supports the shell while the turning tool
is in operation. The end of the shell is faced by means of a facing
tool _C_ which is really a type of facing mill. The end of the shell is
then chamfered by means of a chamfering tool _D_ that removes the sharp
corner.

[Illustration: Fig. 16. Details of Relieving Turning Tool-holder shown
in Fig. 15]

After these operations have been performed, the turret is indexed and
the second face of the turret is brought in line with the chuck. This
operation is accomplished with a relieving tool-holder _E_ carrying a
cutter _e_, which takes a cut 2¹⁄₂ inches along the body of the shell.
An interesting feature of this tool is that on the return stroke of the
turret it swivels back out of the way so that the shell is not scored
by the tool dragging over it. The construction of this tool is more
clearly shown in Fig. 16.

As is clearly shown in this illustration, the turret relieving turning
tool comprises a shank on which is fulcrumed a tool-holding member _B_.
This is slotted out to carry the turning tool _C_ which is clamped
in place by two set-screws _D_ and is adjusted to turn the correct
diameter by means of an adjusting stud and clamping nut _F_ and
_G_. The method of operating this tool is as follows: The fulcrumed
tool-holder _B_ is “held up” by means of a fillister-head screw,
screwed into a stud _H_ and acted upon by a coil spring _I_. A hole to
receive the stud is drilled in the tool-holder _B_, allowing about ¹⁄₁₆
inch clearance. When the tool is in action it has a reverse position
to that shown in the illustration, that is, the turning tool instead
of being parallel with the center line is at a slight angle with it.
In action, as soon as the turret advances, the tool comes into contact
with the work, and the work, turning around, forces the cutting tool
down and consequently depresses the spring, at the same time bringing
the “lower part” of the hole into contact with the extended plug on
the holder. In this way the tool is held rigidly and in contact with
the work. As soon as the turret begins to move back, however, and the
cutting pressure is released, the spring comes into action and throws
up the tool, bringing it out of contact with the work.

Upon the completion of the operation which is accomplished from the
second turret face, the turret is again indexed and the next operation
is performed from the rear cross-slide and the third turret face.
The third operation consists in cutting the grooves for the rifling
band, and, on account of the under-cutting necessary, involves some
interesting points. In order to hold the work rigidly while the
grooving tools are acting on it, a revolving support _F_ is brought
in from the turret. The wide tool _G_ for cutting the band grooves
(this tool removes the greatest amount of the stock) is held on the
rear cross-slide and is of the under-cutting type; that is to say, it
operates under the work or tangentially instead of radially. Held on a
bracket on the third turret face are two tools _H_ and _I_, the purpose
of which is to dovetail the rifling band grooves. These turret tools
are held in a holder working in a slide on the bracket fastened to the
turret face and are operated by a block held on the rear cross-slide.
The action of these three tools, therefore, is simultaneous. The wide
grooving tool, however, is slightly ahead of the dovetailing tools.

[Illustration: Fig. 17. Type of Draw-In Collet and Chucking Mechanism
for holding Forged Shrapnel Shell for performing Second Series of
Operations]

The last operation is accomplished when the turret is indexed to the
fourth position. Here, again, a roller support _J_ steadies the work
while the waving tool is in action on it. The two waves that are formed
are for the purpose of preventing the rifling ring from turning, and
they deviate about ¹⁄₁₆ inch laterally from being a true annular rib.
The tool for cutting these ribs is shown at _K_ and is of the forming
type held in a dovetailed groove in the holder _L_. This also carries
a roll _M_ which contacts with the waved surface of the face-cam _N_,
the curve of which gives the correct out-and-in motions to the waving
tool _K_. The cam face is on a sleeve that is threaded onto the nose of
the spindle of the machine, as is shown to the left of the illustration
opposite the first turret face.


=Method of Holding Shell for Second Operation.=--The second series of
operations on the shell is also performed on the Potter & Johnston
automatic chucking and turning machine. The shell is held at the base
end by a special collet of the draw-in type, as shown in Fig. 17.
Fixed in the nose of the spindle is a positive stop _A_ against which
the shell is held by means of the draw-in collet _B_. This collet
extends into the draw-in rod _C_, to which it is attached. The method
of operating this gripping mechanism differs slightly from that shown
in Fig. 14. In this case the spring collet _B_ is drawn into a tapered
sleeve to clamp it on the work. This is effected by means of lever _D_
which is fulcrumed in a bracket extending from the rear bearing cap of
the machine and operates a sliding cam sleeve _E_. The cam, in turn,
operates fingers _F_, only one of which is shown, the latter acting
upon the draw-in rod _C_ to which the collet is attached. By depressing
lever _D_, the chuck is opened by means of the coil springs _G_ which
act upon the draw-in rod _C_ when the pressure of the fingers has been
released. Lifting up handle _D_ closes the chuck, and depressing it
opens the chuck.

[Illustration: Fig. 18. Tooling Equipment used on No. 6A Potter &
Johnston Automatic Chucking and Turning Machine for performing Second
Series of Operations on Forged Shrapnel Shell]


=Second Series of Machining Operations on Shrapnel Shells.=--The
operations on the shrapnel shell performed in the second setting are
shown in Fig. 18. The relieving tool _A_, held on the first face of
the turret, covers that section of the shell which in the former
operation was held in the gripping jaws. While this cut is being taken,
a turret tool _B_ rough-bores the powder pocket and diaphragm seat.
The relieving tool _A_ is constructed and operated similarly to the
relieving tool described in connection with Fig. 16. It will be noted
here that the threads on the spindle nose are protected by a cast-iron
cap to prevent them from being injured. Upon the completion of the
operation just described, the turret is indexed, bringing the second
face in line with the spindle. Here the diaphragm seat is finished
with a flat cutter _C_, which is held in the boring tool illustrated.
The turret is again indexed into the third position, where the powder
pocket is finished by means of the flat cutter _D_.

The turret is now indexed to bring the fourth face in line with the
spindle where the extreme open end of the shell is turned taper by
means of a tool _E_ that is carried on the front cross-slide and
operated by the turret. By referring to this illustration, it will be
noticed that the taper is turned from the spindle toward the outer
end of the shell and is, therefore, a reverse turning operation. The
tool is caused to move toward the turret by using a rack and pinion to
reverse the movement. On this operation, as well as on the previous
one, one man takes care of four machines.

[Illustration: Fig. 19. Machining Inside of Shrapnel Shell, and
threading with Automatic Collapsible Tap on Potter & Johnston Automatic
Chucking and Turning Machine]


=Third Machining Operation on Shrapnel Shells.=--Before any other
machining operations are done on the shell, it is taken to a lead bath
where it is heated and afterward placed under a press which closes
in the nose or open end of the shell. For machining in the third
operation, the shell is held practically in the same manner as for the
second operation, except that it is gripped farther along the body.
The machining performed in this operation is as follows: On the first
turret face, rough-bore and finish-bore for a distance of 1 inch from
the end of the shell; second turret face, rough-bore the inside of
the shell for a distance of 1 inch back from the thread; third turret
face, finish-form on the inside for a distance of 1 inch back of the
thread; and fourth turret face, thread with a collapsible tap. The
various machining operations on the 3-inch size of shrapnel shells
are performed on a standard Potter & Johnston 6A automatic chucking
and turning lathe. It is recommended that these machines be run in
batteries or units of seven each, four machines being set up for the
first operation, two machines for the second operation, and one machine
for the third operation.

[Illustration: Fig. 20. First Series of Operations on “Frankford” Shell
on a Potter & Johnston 6A Automatic Chucking and Turning Lathe]

[Illustration: Fig. 21. Second Series of Operations on “Frankford”
Shell on Potter & Johnston Automatic Chucking and Turning Lathe]


=Machining “Frankford” Forged Shell.=--The machining of the American
or “Frankford” 3-inch type of high-explosive shrapnel shell is
comparatively easy, inasmuch as there is no nosing to be done, and the
entire shell may be machined at two settings. Fig. 20 shows the way
in which the first operation is taken care of on the No. 6A Potter &
Johnston automatic chucking and turning lathe. The forged shell is held
on an expanding arbor of the same type as that shown in Fig. 15. In
the first turret position, the operations consist in taking a straight
cut across the diameter and facing off the end. The external turning
tool _A_ is of the relieving type, and _B_ is a facing tool that works
on the end. Both of these tools are supported and operated from the
turret. A roll support, not shown, steadies the work while tool _A_
is working. The turret now backs out, and a forming tool, held on
the cross-slide, advances, cuts the rifling band and the semicircular
grooves in the end of the shell, and at the same time chamfers the
corner. Knurl _D_, held on the rear of the cross-slide, is then
advanced. This knurls the bottom of the rifling band groove.

By referring to Fig. 20, it will be seen that the grooves do not
extend entirely across the face of the knurl, but instead two “knurl”
ribs similar to a double thread are formed on the periphery. This
construction makes it possible to sink the knurl into the work to the
proper depth without exerting excessive pressure on the arbor and
throwing it out of line.

[Illustration: Fig. 22. Three-inch Shrapnel Shell made on a Gridley
Automatic Turret Lathe]


=Second Series of Operations on “Frankford” Forged Shrapnel
Shell.=--For the second series of operations, the “Frankford” shrapnel
shell is held in a draw-in collet as shown in Fig. 21. As the shell
has been completely machined on the outside, it is let into the collet
for a considerable distance. For machining, it is shown gripped in
the collet by jaws _A_ and is backed up by positive stop _B_. At the
first turret face, tool _C_ rough-bores the diaphragm seat, tool _D_
bores the thread diameter, and tool _E_ faces and chamfers the end.
The turret is now indexed, and tools _F_, _G_, and _H_ perform similar
finishing cuts. A holder held on the third turret face carries tool
_I_ that chamfers the powder pocket, and at the fourth turret face a
collapsible tap threads the open end.

[Illustration: Fig. 23. Tool set up for Producing the Shell shown in
Fig. 22]


=Making Shrapnel Shells on the Gridley Automatic Turret Lathe.=--Figs.
22 to 25 show a three-inch shrapnel shell made on the 3¹⁄₄-inch Gridley
single-spindle automatic turret lathe. The steel from which the shell
is made is very tough. The specifications are from 125,000 to 135,000
pounds tensile strength, 110,000 pounds elastic limit, a twenty-five
per cent reduction of area, and a twelve per cent elongation. It will
be seen from the above specifications that the steel is, of necessity,
very tough and difficult to work; in addition, a large taper reamer
must be used, and the outside of the shell must be relieved throughout
the central portion. It is also necessary to machine the piece to
extremely accurate dimensions, all of which tends to make the work
still more difficult. Fig. 22 shows a view of the shrapnel shell.
It is approximately three inches in diameter and eight inches long,
and the limits allowed for the sizes are extremely close throughout,
both inside and outside. Figs. 24 and 25 show the successive steps
employed in machining the piece complete, the four views presented
representing the appearance of the work and the operations performed at
each indexing of the turret. Fig. 23 will enable the operation of the
different parts to be more clearly understood.

[Illustration: Fig. 24. Successive Steps and Operations employed in
Making the Shell shown in Fig. 22]

[Illustration: Fig. 25. Successive Steps and Operations employed in
Making the Shell shown in Fig. 22]

While the operation of the Gridley automatic turret lathe is generally
understood by mechanics, it may be well to state briefly the general
principles upon which work is done in the single-spindle machine. In
this type of machine, the position of the work does not change as it
does in the multiple-spindle machine, but the turning is accomplished
by the operation of tools mounted on tool-slides which, in turn,
work on a turret that revolves about a horizontal axis, successively
presenting the tools for operation upon the work. This will be readily
understood by glancing at the illustration Fig. 23. It will also be
noticed from this illustration that the forming tools and cutting-off
tools are operated from a face-cam at the lower part of the machine.
The forming slide is actuated by a cam groove cut in one side of the
cam-plate while the cutting-off slide receives its movement from a cam
groove on the reverse side of this plate.

At the first position of the turret, a large 2¹¹⁄₃₂ inch high-speed oil
drill is run into the bar to a depth of 6¹⁄₃₂ inches, and, at the same
time, a knee-turner located on the tool-slide turns the outside of the
stock, thereby removing the scale from the bar. Referring to Fig. 23,
which shows the turret in the third position, the end of this large
drill is shown at _A_, and, of course, when at work, it would be in the
position of the reamer which is shown at _F_. The time elapsed at the
completion of this part of the work is eleven minutes, five seconds.

[Illustration: Fig. 26. First Chucking on Warner & Swasey Turret Lathe
for machining British Forged Shrapnel Shells]

At the second position of the turret, a smaller drill, 2¹⁄₁₆ inches
in diameter, which is shown at _B_, is run in at the bottom of the
hole previously drilled to a depth of ²⁹⁄₃₂ inch. At the same time a
counterboring tool, which is located at _C_ and which is attached to
the drill with a set-screw, is at work counterboring the end of the
hole in the shell. During the time that this drilling and counterboring
operation is being performed, the forming tool shown at _D_ is being
fed into the outside of the head of the shell, finishing the three
grooves as shown; in addition, a sizing tool _E_, which is at a fixed
distance from the forming tool, comes in and sizes the work to exactly
the right length. The time elapsed up to the finishing of this part of
the work is thirteen minutes, thirty-five seconds.

[Illustration: Fig. 27. Diagram Illustrating Position and Relation of
Tools for First Chucking on British Forged Shell]

At the third position of the turret, which, by the way, is the one
shown in Fig. 23, the large taper reamer _F_ is run in, which operation
removes the bulk of the stock for the taper, and a second step at the
end of this reamer finishes the extreme end of the hole at the bottom
of the shell. The blades of this reamer are nicked to break the chips
as they are being formed. Before the reamer begins to cut, the knurling
tool _H_ is brought against the work (while it is on the high speed)
by the cutting-off slide, which, of course, results in a better knurled
section than would result if the knurling of the piece were done at a
lower speed. During the reaming operation, the cutting-off tool _G_
is run in part way to facilitate the final severing of the piece. In
addition, the relieved part of the work is turned by a tool mounted in
a tool-holder on the slide of the turret. This tool is shown at _I_
and it is operated by a templet _J_ which has a raised projection that
throws the tool into the work after it has reached the right position
with relation to the length of the shell. The total time elapsed up
to the finishing of this part of the work is twenty-two minutes,
thirty-five seconds. At the fourth and last position of the turret, a
finishing reamer sizes the outer end of the interior of the shell and
is withdrawn but part way, so that, when the cutting-off slide comes in
and finishes severing the piece, the shell is caught on the reamer and
not allowed to drop and possibly be injured by so doing.

[Illustration: Fig. 28. Set-up on Warner & Swasey Turret Lathe for
Second Series of Operations on Forged Shrapnel Shell]

The average total time for making this piece complete is twenty-seven
minutes. On account of the rigidity of the tool support, the tools do
not require sharpening more often than once for fifty pieces, with the
possible exception of the cutting-off tool, which must be sharpened
after about half that number of pieces have been completed.


=Using Warner & Swasey Turret Lathe for Machining Forged Shrapnel
Shells.=--In Fig. 26 is shown a typical set-up on a Warner & Swasey
No. 2A universal hollow-hexagon turret lathe for machining an 18-pound
shrapnel shell forging. The arrangement of the various tools for
performing the first series of operations is more clearly illustrated
in Fig. 27, to which reference should now be made. The forging is
located for machining on a special arbor fitted into the spindle and
carrying two spring-controlled centering bushings _A_. These serve to
locate the shell, which is then gripped by the floating jaws of the
chuck on the external diameter, and a stop on the end of the arbor
locates the shell from the bottom of the powder pocket.

[Illustration: Fig. 29. Diagram Illustrating Sequence of Operations
performed at Second Chucking]

The first operation consists in taking a cut from the external
diameter with a special box-turner provided with a roll steadyrest
and carrying two turning tools. The second operation is handled from
the cross-slide, the shell forging meanwhile being supported by a
roll steadyrest clamped to the turret. In this operation the closed
end of the shell is faced with tool _C_, the corner rounded, and the
band groove formed with forming tool _D_. The third operation--first
chucking--is performed with tool _F_ which produces the waves in the
band groove, and is operated in the following manner: Referring to the
lower left-hand corner of the illustration, it will be seen that a
roll _G_ is brought in contact with the face-cam _B_, thus giving the
desired oscillating movement to the waving cutter. The fourth and final
operation consists in under-cutting the band groove with a tool clamped
to the turret. This tool gages from the end of the shell by a revolving
stop _H_, and is provided with two slides, set at the desired angle
to each other and the work, carrying under-cutting tools _I_ and _J_.
These slides are operated by handle _K_.

[Illustration: Fig. 30. Third Chucking Set-up on British Forged
Shrapnel Shell]

The second chucking on this shell is handled as shown in Figs. 28 and
29 on the same type of machine. As shown in Fig. 29, the shell for
this operation is gripped in an automatic chuck, and a stop _A_ for
locating it is held in the spindle. The first operation consists in
roughing out the powder pocket and diaphragm seat with a cutter _B_,
and rough-turning that portion of the shell held in the chuck in the
previous chucking with a tool _C_. This tool is held in the cross-slide
toolpost, and is controlled in its movement by a special guide fastened
to the regular taper-turning attachment. The second operation finishes
the powder pocket and diaphragm seat with a cutter _D_.

[Illustration: Fig. 31. Diagram Illustrating Relation of Tools for
performing Third Series of Operations]

[Illustration: Fig. 32. First Chucking on French Shell made from Bar
Stock on Warner & Swasey Turret Lathe]

After the second chucking, the shell is heated on the nose, closed
in and is then brought back to the turret lathe, when the operations
are performed as shown in Figs. 30 and 31. Here, again, the forging
is held in the automatic chuck and is located by a plug _A_ in the
spindle. The first series of operations consists in boring, facing
and chamfering the nose with a counterbore _B_, and at the same time
turning the external radius on the nose with a tool _C_. Tool _C_ is
held in the cross-slide square turret and is controlled in its movement
by a special guide fitting on the regular taper-turning attachment.

The second operation, shown to the left of the illustration, consists
in machining the radius inside the nose with a tool _E_, controlled
in its movement by the special guide _D_, as previously mentioned.
The third and final operation consists in cutting the thread with a
collapsible tap _F_.

[Illustration: Fig. 33. Second Chucking on French Shrapnel Shell]


=Using Warner & Swasey Turret Lathe for Machining Bar-stock Shrapnel
Shells.=--The method of machining shrapnel shells from bar stock
differs somewhat from that used for forgings, and is handled on a
No. 2A universal hollow-hexagon turret lathe. In this particular
case, the shell blank, previous to machining in the turret lathe, is
rough-drilled in a high-powered drilling machine to the bottom of the
powder pocket. Assuming that this has been accomplished, the operations
for the first chucking are then carried on as illustrated in Fig. 32.
Here the shell is held in an automatic chuck and is located by a stop
_A_. The first operation consists in counterboring the mouth with the
counterbore _B_, and rough-turning the external diameter with tool _C_;
second, counterboring with the cutter _D_ and turning further along the
shell with a tool _E_; third, finishing the bottom with a cutter _F_
and facing the end of the shell with a tool _G_.

[Illustration: Fig. 34. Third and Final Chucking on French Shrapnel
Shell]

In the second chucking, the operations shown in Fig. 33 are performed.
Here the shell is reversed in the automatic chuck and is located, as
before, by a stop _A_. The first operation consists in turning that
portion of the body held in the chuck in the previous chucking with a
roll-supporting turning tool _B_. Second, supporting the shell with a
roller support _C_ held on the turret, facing the end with a tool _D_,
and chamfering the band groove and the end with a cutter _E_ held on
the cross-slide square turret. The third operation is to support the
shell from the turret, knurling with a knurl _F_ from the cross-slide
square turret. Fourth, taper-turn from the end to the band groove with
a tool _G_, guided by the taper-turning attachment.

For the third chucking, the shell, as indicated in Fig. 34, is held in
the same manner as for the first chucking. First, it is recessed with
a tool _A_ and brought into action by operating the special holder
which has a cross-sliding movement; second, it is bored and faced
with a counterbore _B_ from the turret, and taper-turned with a tool
_C_ operated by a special guide from the taper-turning attachment. In
the third operation, the thread in the nose is rough-chased with a
tool _D_, controlled in its movement by the chasing attachment of the
machine; fourth, the thread is finished with a tap and tap-holder _E_.

[Illustration: Fig. 35. Diagram showing Method of holding and
performing First Series of Operations on Forged Shells on “Lo-swing”
Lathe]


=Machining Shrapnel Shell Forgings on the “Lo-swing” Lathe.=--By adding
a simple carriage to its “Lo-swing” lathe, the Fitchburg Machine Works,
Fitchburg, Mass., has adapted this machine for machining shrapnel
shells of different types. The following data and illustrations refer
particularly to tooling used for machining the Russian and French
shells. On the Russian shell, after centering, the forging _A_ is held
on a special arbor _B_ shown in Figs. 35 and 36. Placed over this arbor
is an expanding collar _C_, the inside surface of which is chamfered to
fit against surface _D_ on the stem of the arbor. The section of the
arbor next to the spindle is threaded and a large nut and handwheel
_E_ are turned to pull the sliding sleeve _C_ along the arbor and thus
expand it to firmly grip the inside of the shell forging. Sleeve _C_ is
connected to the nut _E_ by a threaded collar _F_. After the forging is
securely located on the arbor, which it should be understood extends to
the bottom of the powder pocket to gage it for length, the tail-center
_G_ is run in to support it.

[Illustration: Fig. 36. Set-up for performing First Series of
Operations on Russian Forged Shell on “Lo-swing” Lathe]

To those familiar with the “Lo-swing” lathe, it will be appreciated
that its chief efficiency lies in its system of multiple turning
tools. Thus, on this job, tools _H_, _I_, _J_, _K_, _L_, and _M_ are
all mounted on one slide, and in the illustration are shown in the
positions they occupy after taking their respective cuts. At the
beginning of the cut, turning tools _K_, _L_, and _M_ are drawn back
clear of the work to allow sufficient clearance for tools _H_ and _I_
to operate. With the tools drawn back and the carriage at the extreme
right of the bed, tool _H_ is the first to come in contact with the
work. This tool takes a roughing cut over the body of the forging,
finishing at the radius on the nose.

Tool _H_ is controlled in its action by a former pin on the tool-slide,
held in contact with the face of cam former _O_ by a stiff spring.
Former slide _O_ takes the place of the regular taper-turning former
ordinarily used on the “Lo-swing” lathe. When the former pin in the
slide carrying tool _H_ reaches point _P_ on former _O_, the tool is
withdrawn to conform with the shape shown at _N_ on the forging. The
tool is then fed in further toward the axis of the arbor, until the
former pin reaches point _Q_ on the slide, when the radius on the nose
is completed. Tool _H_ is the only one mounted on a taper-turning block.

[Illustration: Fig. 37. Diagram showing Method of performing Second
Series of Operations on Forged Shrapnel Shells on “Lo-swing” Lathe]

Just after tool _H_ passes point _N_, tool _I_ commences to cut at
the end of the forging, taking a finishing cut and ending up in the
position in which it is shown in the illustration. After tool _I_
reaches this position, the other tools _J_, _K_, _L_, and _M_ are
brought into action. Tools _K_, _L_, and _M_ are so situated on the
carriage that no lateral feeding is required. When these tools are in
action, the roller support _R_ takes the thrust. Tool _K_ roughs out
the band groove and is fed into the work by a handwheel. Tool _L_ cuts
the groove for attaching the brass case to the shell, and tool _M_,
carried on the same block, faces the end. Tools _K_, _L_, _M_, and _S_
are located on the same carriage and are fed in together. Tool _S_
rounds the corner of the shell. The carriage on which tools _K_, _L_,
_M_, and _S_ are located is now drawn back out of the way, and the
entire carriage moved over so that tool _J_ can be used to under-cut
the rifling band groove. After cutting off the center projection, the
first series of operations on the shell is completed.

[Illustration: Fig. 38. Set-up on “Lo-swing” Lathe for performing
Second Series of Operations on Russian Shell]


=Second Series of Operations on the Russian Shell.=--The second series
of operations is performed on the inside of the shell on the “Lo-swing”
lathe, which is provided with a special turret for this purpose. As
is shown in Figs. 37 and 38, the shell _A_ is held in special collet
jaws _B_ that have a two-point bearing on the shell. Stop _C_ in the
spindle locates the shell in the chuck. To manipulate the chuck for
tightening it on the work, handwheel _D_ is turned, carrying with it
the nut _E_ and ring _F_. Ring _F_ carries pins sliding in slots in
sleeve _H_ and driven into collet _B_, so that when nut _E_ is drawn
back it also carries collet _B_ into the taper in sleeve _H_, closing
the collet on the work. Turning handwheel _D_ in the opposite direction
releases the grip of the collet _B_ on the work. The first operation is
performed with tools _I_, _J_, _K_, and _L_. Tool _I_ bores the powder
pocket, tool _J_ roughs the diaphragm seat, tool _K_ rough-turns the
thread diameter at the shell mouth, and tool _L_ faces the end. The
turret is now indexed, and boring-bar carrying tool _M_ is brought
into operation. This tool turns the curved interior of the shell. To
accomplish this, the turret locking-pin is removed, allowing the turret
to float on its central axis. Fastened on the ways of the lathe at the
rear of the turret by a clamp _O_ is the cam bracket _N_ carrying the
guiding cam _P_. This cam, through pins _Q_ and _R_ in bracket _S_,
controls the float of the turret and guides the cutting tool _M_. In
the illustration, the tool is shown at the end of the cut. It will
also be noted that one surface of the cam is curved and the other is
straight; therefore, to compensate for this and also to steady the
turret, pin _R_ is backed up by a spring. Clamp _O_ is now released and
bracket _N_ moved back to allow the turret to be indexed. Bracket _N_
is located, when brought into the operating position, by a stop on the
bed of the lathe.

[Illustration: Fig. 39. Diagram showing Method of machining French
Shells on “Lo-swing” Lathe--First Series of Operations]

[Illustration: Fig. 40. Diagram showing Method of holding and applying
Tools on “Lo-swing” Lathe for performing Second Series of Operations on
French Shell]

In the third position, tool _R_ finishes the powder pocket, _S_ the
diaphragm seat, and _T_ the thread diameter, whereas _U_ acts as an
adjustable stop for the depth of the various tools. The fourth and last
operation is tapping with a collapsible tap _V_. This completes the
machining of the Russian shell on the “Lo-swing” lathe.


=Machining French Shrapnel Shell on “Lo-swing” Lathe.=--The machining
of the French shrapnel shell is well suited to the “Lo-swing” lathe.
A great many of the French shells are made from solid bar stock, and
when this is the case, the first operation, performed as shown in Fig.
39, consists in rough-drilling. If the shell is made from a forging,
this operation, of course, is dispensed with and the first tool used
carries boring and facing cutters, as shown at _A_, _B_, _C_, and _D_.
These rough-bore the three diameters on the inside of the shell and
face off the end to length. The next operation is accomplished with
two finishing boring tools _E_ and _F_, the depth of which is obtained
by an adjustable collar _G_ that comes against the produced with a
collapsible tap _H_. The turret is then indexed two holes, bringing the
special recessing tool into position. This tool is of the cross-slide
type and carries a back recessing cutter _I_. This completes the first
series of operations on the shell.

[Illustration: Fig. 41. Set-up on “Lo-swing” Lathe for performing
Second Series of Operations on Straight Type of French Shell]


=Second Series of Operations on Shell. French=--The second series of
operations on a French shell is accomplished as shown in Fig. 40. Here
the shell is held in the same manner as described in connection with
Fig. 35. The forging is placed on arbor _B_ that has an expanding
sleeve _C_ operated by the hand-clamping wheel nut _D_. Eight cutting
tools are located on the carriage. Tool _A_ turns the diameter at the
open end of the shell, _B_ the central part, _C_ cuts the band groove,
_D_ chamfers the section adjacent to the band groove, _E_ chamfers
the end of the shell, and _F_ knurls the band groove. Roll _G_, in
connection with roll _H_, supports the shell while the knurling is
being done, whereas tool _I_ faces off the end of the shell. At the
beginning of the cuts, tools _C_, _D_, _E_, and knurl _F_, also roll
_G_ and tool _I_, are withdrawn. This permits tool _A_ to cut the front
end of the shell at the beginning and finish the diameter at the open
end of the shell. Tool _B_ next comes into action and turns the central
part of the shell. Tool _C_ is then located in the correct position for
the band groove and the carriage on which tools _C_, _D_, and _E_ are
located is fed straight in, cutting the band groove and chamfering.
Knurl _F_ is then brought into position to knurl the groove, with roll
_G_ backing up the work against roll _H_. The last operation is to cut
off the center projection with tool _I_.

Fig. 41 shows the tool set-up on the “Lo-swing” lathe for machining
the straight type of French shell, in which two tool-blocks are used
for doing the straight turning. The leading tool turns the end of the
shell a little larger than the main body. The procedure for grooving,
knurling, and facing the shell is that previously described for the
forged shell, which is shown in Fig. 35. On the French shrapnel shell
the second operation follows directly after the first, whereas on
the Russian forged shell a nosing-in operation comes between the two
machining operations.

[Illustration: Figs. 42 and 43. Set-up and Tool Equipment on the
“Libby” Turret Lathe]

=Using the “Libby” Turret Lathe for Machining Shrapnel Shells.=--One of
the many ways of machining a shrapnel shell is illustrated in Figs. 42
and 43. This shows the set-up on the “Libby” turret lathe, manufactured
by the International Machine Tool Co., Indianapolis, Ind. In the first
chucking, the forging, as shown at _A_, is held on a special solid
arbor provided with a series of corrugations where it contacts with
the forging. This, in addition to providing a rigid support, assists
in gripping, and the shell is also gripped by a pair of chuck jaws
that act as drivers. First, a gang tool-holder carrying three stellite
turning tools _o_ is brought into position, and the cutting is
started, continuing for a distance of one-third of the length turned.
To provide additional support, a roller back-rest, carrying a facing
tool, is brought in to steady the work, and, as it is fed forward, the
end of the forging is faced off and chamfered.

[Illustration: Figs. 44. and 45. Machining Shrapnel Shell Forgings on a
22-inch Extra-heavy Turret Lathe]

The second operation on the first chucking is shown at _B_. Here the
cutter _a_ is brought in first and starts the band groove, after which
the under-cutting tool _b_ is brought in to under-cut the edges of
the groove. In the meantime, roller _c_ supports the work. Upon the
completion of the groove, the holder carrying cutter _d_ is advanced to
finish-face the end of the work and chamfer.

The third operation--cutting the waves in the band groove--is of an
interesting character and is accomplished as shown at _C_. A cam _e_
which is free to rotate with the work is first brought in contact with
it; then the cross-slide is advanced, carrying the waving tool _f_ and
the guide _g_. The guide _g_ fits in the cam groove and controls the
operation of the waving tool.

In the second chucking on the first operation the shell is reversed
in the chuck and is held in the manner indicated at _D_, Fig. 43. The
forging is located in the chuck by a stop-collar _h_, and is gripped on
the external diameter by the jaws of the chuck. A stepped boring tool
carrying five inserted blades is brought in to rough-bore the internal
diameters and machine the shell to the proper thickness at the bottom
of the powder pocket. This tool also carries a facing cutter that faces
off the shell to the proper length. While the boring tool is working,
a broad turning tool, held on the cross-slide, is brought in to bevel
the nose preparatory to closing-in. The next step is to taper-ream the
internal diameter, as shown at _E_. This completes the operations for
the second chucking.

The nose of the shell is now heated and closed in, after which the
third series of operations is performed. The first step in the third
chucking is to bore for the thread and face the end of the shell with
a turret tool, as shown at _F_. The next operation is to machine the
curved contour of the nose of the shell with a special turret tool
as shown at _G_. Here a wide forming cutter _i_, held in a turret
tool-holder, is brought in contact with the work, finishing the nose
of the shell to the proper form. During this operation, the shell is
supported by a roller in the holder.

The next operation is to form the inside of the nose of the shell to
the proper shape, as shown at _H_. This is accomplished with a forming
blade _j_, held in a holder clamped in the toolpost. Following this, a
collapsible tap is brought in from the turret to thread the nose of the
shell, as shown at _I_.

[Illustration: Fig. 46. Method of holding Shrapnel Shells for First
Operation on a 22-inch Turret Lathe]


=Machining Shrapnel Shells on a Heavy 22-inch Turret Lathe.=--Still
another method of machining shrapnel shells in a heavy turret lathe
is shown in Figs. 44 and 45. The shell being machined is an 18-pound
British shrapnel shell made from a forging. It is held on an expanding
arbor for the first operation, as shown in Fig. 46. The arbor is of
the three-point support type and is positive in its grip. Around the
periphery of the nose-piece are located three pinions _A_ capable of
being rotated by a square-ended wrench. These mesh with teeth in bevel
gear _B_ which, in turn, is threaded onto arbor _C_. The forward end of
this arbor is cone-shaped and operates the three gripping fingers in
the open end of the shell, whereas another rod passing through arbor
_C_ and connected to plunger _D_ operates, through the coil spring, the
three fingers used in gripping the shell by the powder pocket. This
arbor holds the shell securely while the machining operations are being
accomplished.

The first operation performed at the first chucking of the work is
shown at _C_ in Fig. 44. Here a turning tool-holder clamped to the
turret and carrying two cutters is advanced and takes a roughing cut
from the exterior diameter of the shell for practically its entire
length. The shell is supported by three roller supports as illustrated.
The second operation at the first chucking is performed from the
cross-slide, as shown at _D_. Here a forming tool of the tangent type
roughs out the rifling band groove, leaving sufficient metal in the
center for the production of the wave ribs. The third operation is
facing off the closed end of the shell from the turret as shown at
_E_, and the fourth operation consists in machining the waved ribs as
shown at _F_. The tool for accomplishing this operation is held on the
cross-slide and is operated from a face-cam on the nose of the spindle.

[Illustration: Fig. 47. Cutting Square Thread in Nose of French
Shrapnel Shell In “Automatic” Threading Lathe]

In the second chucking the shell is held in a three-jaw scroll chuck.
The first operation is to rough-bore the inside of the shell and powder
pocket with a tool _G_, Fig. 45, held in the turret; directly after
this a finishing tool of the same shape is brought in, finishing the
surfaces previously roughed out. The second operation is to face off
the open end of the shell and taper-form back of the nose from the
cross-slide, as shown at _H_, and at the same time turn that portion
of the exterior surface of the shell not machined in the previous
operation with a tool clamped to the turret as shown at _I_.

[Illustration: Fig. 48. Threading Base End of Bar-stock Shrapnel Shells
in “Automatic” Threading Lathe]

Previous to the third chucking, the nose of the shell is heated and
closed in. The shell is then held in a three-jaw scroll chuck provided
with special jaws. The first operation, as shown at _J_, consists
in boring and turning the nose of the shell with a tool held in the
turret. Following this, the hole is reamed with a standard reamer and
tapped with a collapsible tap. Both of these tools are held in the
turret, but are not shown in the illustration. This completes the
machining operations on the shell.


=Threading Shrapnel Shells on “Automatic” Threading
Lathes.=--Considerable difficulty has been experienced in cutting the
square thread in the nose of the French shrapnel shell. One method
which accomplishes this operation satisfactorily is shown in Fig. 47,
and is accomplished on a 12-inch “Automatic” threading lathe built by
the Automatic Machine Co., Bridgeport, Conn., and equipped with special
tools for this purpose. Referring to this illustration, it will be seen
that two tools are used--a roughing tool _A_, and a finishing tool _B_.
Tool _A_ roughs out the thread to a shape similar to the Acme type of
thread, whereas tool _B_ squares it up. The roughing and finishing
tools are held on the forward and rear carriages, respectively, and
are operated simultaneously, being advanced throughout the length of
the thread, withdrawn and returned to start a new cut. The method of
operating the tools is one of the chief features of the “Automatic”
threading lathe.

[Illustration: Fig. 49. Turning, facing, and threading Plugs for Closed
End of Bar-stock Shrapnel Shells in “Automatic” Threading Lathe]

The base end of shrapnel shells when made from bar stock is as a rule
bored out and a plug inserted to eliminate any piping effect in the
bar. Fig. 48 shows the method of accomplishing this operation on a
12-inch “Automatic” threading lathe. The work is held in a three-jaw
universal chuck and is supported by a roll steadyrest comprising two
rolls that are located beneath the work. On the extended end of the
rear roller stud is fastened a swinging stop that is used for locating
the base of the shell in the correct position ready for threading. The
base of the shell is counterbored in another machine, previous to the
threading operation. The threading is done with a circular tool held
on a special internal threading tool-holder, the latter being retained
in the toolpost carriage. The threading tool-holder can be moved
longitudinally to bring it into the proper relation to the work. It is
also held so that the cutting edge is turned upside down as this action
forces the work down in contact with the roller supports. By handling
the work in this manner, a steadyrest of the ordinary type is dispensed
with and the operation of the attachment facilitated.

[Illustration: Fig. 50. Grinding Shrapnel Shells on a Norton
Special-purpose Grinding Machine]

One method of making plugs for the base end of shrapnel shells when
made from bar stock is shown in Fig. 49. For this work, a 12 by 4
“Automatic” threading lathe equipped with special tools designed for
this purpose is used. The machine is provided with a draw-in collet
chuck that holds the rough-forged blank. The order of handling the
operations on this machine is to use the rear tool _A_ for turning
the external diameter of the plug. This is handled at the same rate of
feed as that required for threading, so that it is sometimes necessary
to take more than one cut, depending on the amount of material left on
the diameter. The vertical slide _B_ is for facing only and carries a
cutting tool _C_. This is supposed to finish the face in one cut, but
as the work will spring considerably, a light finishing cut is taken
when the tool is being drawn back from the center to the circumference
of the work. The threading tool _D_ is held on the front toolpost
and is of single-point construction. The feed given to this tool is
automatically controlled, both as to pitch and depth of cut at each
traverse.

[Illustration: Fig. 51. Diagram showing Scleroscope Hardness Test of
Heat-treated Shrapnel Shell at Various Points along its Surface]

In actual operation, both the threading and turning tools are in motion
all the time on the work, but the tools are independently controlled
so that either one can be operated separately. A stop is provided on
the back toolpost so as to turn each plug to the same diameter. The
automatic throw-out for the feed of the threading tool is set from the
front handle on the ratchet and pawl as regularly furnished on the
“Automatic” threading lathes.


=Grinding Shrapnel Shells.=--An increasingly large number of shrapnel
shell manufacturers are finishing the steel shell by grinding instead
of finish-turning. That is, the exterior surface of the shell is
rough-turned to within from 0.030 to 0.080 inch of the finished size
and is then finished to the required limits and shape by grinding,
as shown in Fig. 50. It is claimed by the advocates of grinding that
the finishing operations are more speedily performed in this manner
and that a more accurate and concentric shell is produced. They also
point out the fact that portions of the shell are so hard that it is
extremely difficult, if not impossible, to turn it in the allowable
time.

The varied heat-treatment given to the shell on the closed end and nose
leaves it harder in some sections than others, as indicated in Fig.
51. The section _E_, 2¹⁄₂ inches from the closed end of the shell,
must strike from 42 to 50 on the scleroscope, and the section _A_ at
the nose must strike between 20 and 25. The section marked _D_, or
that part of it to the left of the line that marks the limit of the
heat-treating on the closed end, has not been heat-treated at all, and
partly on this account, and also because of the gradually diminishing
thickness of the shell along this section, it strikes between 40 and
45, decreasing as the thickness of the wall diminishes, until at _C_
the section strikes but 35. Section _B_, adjacent to the annealed nose
of the shell, strikes about 30 on the scleroscope.

[Illustration: Fig. 52. Two-operation Method of grinding Shrapnel
Shells on Norton Grinding Machines]

On the other hand, some manufacturers are not putting the shell through
this heat-treating and tempering process, and omit the annealing and
machining of the nose after the nosing-in operation. This leaves the
nose with considerable stock to remove and in such a condition as
regards hardness that the grinding machine becomes a necessity. In
the face of these varying degrees of hardness of the shrapnel shell,
it will be seen that it is difficult to secure wheels of the right
grain and grade to suit all of these conditions. With this information
in mind, we can more intelligently take up the actual grinding of the
shell. The Norton Grinding Co., Worcester, Mass., has been actively
engaged in developing methods of grinding shrapnel shells and the
following illustrations and descriptions apply to this work.

[Illustration: Fig. 53. Three-operation Method of grinding Shrapnel
Shells on Norton Grinding Machines]

Fig. 52 shows the two-operation method of grinding the shrapnel shell.
Section _A_ at the open end of the shell is covered by a wide-faced
wheel formed to shape, that finishes the radius on the nose at one
in-feeding of the wheel. Sections _B_, _C_, and _D_ are covered by a
wide-faced wheel, formed to shape so as to finish these three surfaces
at one in-feeding of the wheel. Section _E_ at the closed end of the
shell is finished completely by turning.

Some manufacturers use a three-operation method of grinding the
shrapnel shell as illustrated in Fig. 53. In this case, the sections
_A_ and _D_ are first ground with the same wheel, as American
manufacturers deem it advisable to grind surface _A_ rather than
to finish it by turning. The second stage in this grinding is the
finishing of the nose _E_ with a formed wheel, and the third stage is
the finish-grinding of the body at points _B_ and _C_.


=Two-operation Method of Grinding Shrapnel Shells.=--The procedure
followed in grinding shrapnel shells by the two-operation method is
first to screw plugs into the open end of the shells, as shown in Fig.
52. The outer ends of these plugs are centered, and the projection
left on the closed end of the shell with the center intact acts as a
means of supporting the shell. Some of the Canadian manufacturers vary
this practice by cutting off the center projection on the closed end
of the shell and fitting a cap with a center hole over the closed end.
Others use a ball-bearing cup center to carry the closed end. American
manufacturers, however, leave the center projection on the shell until
after the grinding has been finished.

[Illustration: Fig. 54. Radius Wheel-truing Device for forming Grinding
Wheel for grinding Shrapnel Shell Nose]

In grinding the nose end of the shell, the amount of metal removed
varies from 0.020 to 0.090 inch on the diameter. The grinding wheel
operates at from 6000 to 6250 surface feet per minute. The speed of the
work is 75 revolutions per minute, or a surface speed of practically
75 feet, and the machine used is a Norton 6 by 32 plain grinder. The
wheel used is generally 14 inches in diameter by 2¹⁄₄-inch face. The
wheel requires truing for every five to twenty shells, depending upon
the amount of metal removed and the hardness of the shell. For truing,
a simple radius fixture carrying a diamond is used. Fig. 54 shows this
wheel-truing device clamped on the grinding machine bed. It is applied
in the same manner as the usual steadyrests used for supporting the
work. The diamond is mounted in a swinging arm that is operated by a
hand lever as shown. By successive cuts across the wheel, the desired
shape is attained.

[Illustration: Fig. 55. Norton Special Form Wheel-truing Device for
truing Wheel for grinding Shrapnel Shell Body]

For grinding the body either a 10 by 24 special-purpose or 10 by 36
Norton grinding machine is employed. The amount of metal removed
from the body varies from 0.030 to 0.075 inch on the diameter, and
the limits vary from 0.002 to 0.010 inch, depending largely on the
requirements of the plant in which the work is being done. The wheel
used on the body is 20 inches in diameter and is of the ring-wheel
type. It will be noticed in Fig. 52 that the wheel for grinding the
body is also formed to shape. The method of truing the wheel for
shaping the shrapnel shell body is shown in Fig. 55. This attachment
is clamped to the front of the grinding machine bed and at the top of
the bracket is fitted a slide _A_ operated by handwheel _B_. Upon the
face of this slide nearest the grinding wheel is pivoted an angular
arm _C_ that supports the diamond _D_ at its lower end. Under the end
of the upper arm is a spiral spring that keeps the diamond normally
back from the wheel. A plate former _E_ clamped to the bottom face of
the bracket is shaped to agree with the form to be given the wheel. At
the lower extremity of the arm and behind the diamond is mounted a roll
_F_ that bears constantly against form _E_. When the diamond slide is
reciprocated by turning the handwheel, the diamond is made to traverse
a path conforming with the cam that guides it. By moving the wheel in
toward the diamond and making successive traversings of the diamond,
the wheel is given the desired shape.

[Illustration: Fig. 56. Besly No. 14 Ring Wheel Grinder equipped for
grinding Shrapnel, but shown without Hoods and Water Attachments]

[Illustration: Fig. 57. Fixture used on Besly No. 14 Ring Wheel Grinder
for grinding Center End from Shrapnel Forgings]


For grinding the body, the wheel must be trued after every ten to
twenty-five shells are ground, depending upon the amount of metal
removed and the hardness of the shell. In grinding shrapnel shells, the
usual method is to fit a lot of the shells with the driving plugs and
carry them all through to completion before removing the plugs.


=Removing Center End From Shrapnel Forgings.=--For performing
practically all the machining operations on the shell, a center
projection is left on the closed end of the shell for supporting it.
This, of course, must be removed before the shell is completed. One
method of doing this is to use a Besly No. 14 ring-wheel grinder
equipped with a special fixture. A Besly grinder fitted up for this
work is shown in Fig. 56, and the fixture used for holding the shell
is shown in Fig. 57. The machine, as furnished, is arranged for wet
grinding, but is not so fitted up in the illustration. The fixture
is fastened to the geared lever feed table and is of simple design.
It is provided with a backing-up stop _A_, the work resting in two
semi-spherical groove projections on the fixture. The operator simply
holds the shrapnel shell in place by hand and then feeds it in against
the wheel and traverses it past in the usual manner. The time for
removing a ⁵⁄₈-inch diameter stub end projecting ³⁄₈ inch from the body
of the shell is less than a minute.

[Illustration: Fig. 58. Tools for making Base of Powder Cup]

[Illustration: Fig. 59. Tools for making Top Member of Powder Cup]


=Press Tools for Making Powder Cup.=--In the British shrapnel shell,
the powder in the base of the shell used for exploding it and ejecting
the lead bullets, etc., is held in a tin-plate powder cup. This is
completed in the punch press in the manner shown in Figs. 58 and 59,
and comprises two parts, a base and a top. The base is made from tin
plate 0.022 inch thick, whereas the top is made from 0.036 inch thick
tin plate. The bottom of the cup is completed in one operation with
the punch and die shown in Fig. 58, which is held in a single-action
press. It is turned out from a blank 3⁷⁄₃₂ inches in diameter and is
cut out and formed in one operation. The completed size is 2¹⁄₄ inches
diameter by ⁷⁄₈ inch high. After cupping, the top edge is trimmed in
a turret lathe. The press operations on the top, as shown in Fig. 59,
are a little more complex. The first operation consists in cutting
out a blank 2¹⁹⁄₃₂ inches in diameter. Then the edge is turned up with
another punch and die shown in the center of the illustration. The next
operation is piercing the center with the punch and die at the right,
and the last operation is drawing out a flange around the pierced hole.
The tools for this operation are shown to the extreme right, as is also
a completed powder cup. The final operation on the cup consists in
soldering the top to the base.

[Illustration: Fig. 60. Diagram illustrating “Twelve-punch” Method of
making Shrapnel Bullets from Lead Wire]


=Shrapnel Bullets.=--The most deadly and effective parts of a shrapnel
are the lead bullets which are held in the shell. When the timing fuse
explodes the powder in the base of the shell, the nose is blown off
and the bullets are thrown out in a cone shape. The range covered by
these bullets in the 18-pound shrapnel shell is about 250 square yards.
The lead bullets, which in most shrapnel are ¹⁄₂ inch in diameter, are
made from several different compositions, but consist chiefly of 87¹⁄₂
parts lead and 12¹⁄₂ parts antimony. The number of bullets carried in
shrapnel shells of the different governments varies. There are 252 in
the American 15-pound shell, and 235 or 236 in the British 15-pound
shell. The bullets used by the U. S. government have six flattened
sides, to facilitate packing, whereas those used by foreign governments
are spherical.

There are several methods of making shrapnel bullets. One is to cast
the bullets in iron molds, which are split in the center, so that the
bullet can be removed when cast. Another is to cut off slugs from lead
wire and strike these between dies in a heading machine. The bullet
heading machine takes the wire from a reel, cuts it off, forms it and
trims off the resultant flash automatically. In making the American
bullets, a second operation follows, consisting in flattening the
sides. The Waterbury Farrel Foundry & Machine Co. furnishes unit
equipments for doing this work. For the flattened bullets, the unit
consists of one hydraulic wire extruding press and fourteen heading
machines capable of giving a production of 850 bullets per minute. For
the spherical bullet, the unit equipment consists of one hydraulic
extruding press and eight heading machines, giving a production of 950
bullets per minute.

The method of casting lead bullets in ordinary molds is antiquated, and
another method somewhat similar to that just described has taken its
place. The first step is to produce the wire from which the bullets are
eventually made. This is accomplished in two ways. The first is the hot
metal process and consists in pouring the molten lead into a cylinder,
from which it is extruded through a die by a plunger advanced into the
cylinder. By this method, it is necessary to allow the metal to settle
before the press can operate. An improvement over this is utilized in
presses built by a hydraulic lead press manufacturer of Brooklyn, and
consists in first casting ingots of the required diameter and length
and then charging the press with these instead of pouring the molten
lead into the press chamber. Two presses have been designed for this
process. One has a capacity of 700 tons and is charged with ingots
weighing 150 pounds, whereas the other has a 900-ton capacity and is
charged with 200-pound ingots. The product from these two machines is
1800 pounds of lead wire from the small and 2500 pounds from the large
press per hour. The wire as it is extruded from the die is wound on a
reel carrying 2000 pounds of wire.

There are two principal types of swaging machines used for making these
lead bullets from wire. One carries a single set of dies, whereas the
other carries twelve sets of tools. The operation of the latter will
be described. Referring to the diagram, Fig. 60, twelve reels of lead
wire--not shown--are arranged in tandem on stands behind the press, six
reels in a row. The wire is conveyed from these reels to the dies by
a feeding mechanism, being guided to the individual tools by a plate
_A_, having twelve U-shaped impressions in its top edge. The wire now
passes over a spring _B_ which serves to lift it up slightly at each
stroke of the press. The tools _C_ and _D_, as shown, are provided
with half-spherical depressions in their adjacent faces and are set so
that they come within ¹⁄₆₄ inch of meeting. The dies are guided and
controlled in action by a special mechanism, and the press in which
they are carried operates at 70 revolutions per minute. This gives a
rated production of 840 bullets per minute. As is clearly indicated in
the illustration, considerable scrap is formed in making lead bullets
by this process--in fact the scrap is about 33 per cent of the reel of
wire; also owing to the setting of the punches a slight fin is formed
around the periphery of the bullet.

After forming, the bullets are taken to a tumbling machine where
they are tumbled for one hour. No other material is put into the
tumbling barrel, but the action of the bullets working on themselves
satisfactorily removes all the fins. Both the swaging and tumbling
operations must be carefully watched because of the necessity of having
the bullets a certain weight. The allowable variation on one pound of
bullets is one dram, and there are forty-one bullets to the pound. Ten
pounds of lead rod make 6¹⁄₂ pounds of bullets, and the scrap resulting
from the swaging operation is remelted and used over again. After
tumbling, the bullets are inspected and are then ready for use.




CHAPTER V

MAKING FUSE PARTS


Combination timing and percussion fuses comprise a large number of
small parts made from different metals and alloys, and are produced in
various ways. Some of the parts are made from brass rod or alloys of
copper and aluminum, whereas others are made from hot-pressed forgings
and are machined after being formed to shape. In the following, a brief
description of several different methods of making the most important
fuse parts will be illustrated and described, together with details
regarding the forging tools used for the socket and plug.

[Illustration: Fig. 1. Tools used in forging Brass Fuse Socket]

[Illustration: Fig. 2. Diagram showing Construction of Tools used in
forging Fuse Socket]


=Forging the Fuse Socket.=--The fuse socket, which screws into the nose
of the shrapnel shell and acts as a base for the fuse, is made from a
special forgeable alloy casting containing 40 per cent copper, 58 per
cent zinc, and 2 per cent lead. The first step in this process is to
melt the above constituents in the usual manner and then to cast the
slugs in sand molds, six to eight being gated together. These castings
are made 2¹¹⁄₁₆ inches in diameter by ¹¹⁄₁₆ inch thick, as shown in
Figs. 1 and 2. There are several methods in use for forging the plugs,
but the general principle is the same. In this particular case, a No.
23 Bliss press capable of exerting a pressure of 250 tons is used. The
castings are placed in the furnace where they are allowed to “soak”
at a temperature varying from 1200 to 1300 degrees F., or, in other
words, until they reach a dull red color. One casting at a time is then
quickly removed and placed in the impression of the die shown to the
right in Fig. 1 and in detail in Fig. 2. The working parts of these
dies are made from Jessop’s high-carbon tool steel and one blow of the
press completes the forging, turning out about 3000 in ten hours. The
tools used for this purpose are of interesting construction, as shown
in Fig. 2. They comprise a lower die _A_ machined out to the shape of
the finished forging and carrying an ejector, and lower former _B_
operated by plunger _C_ which ejects the forging if it sticks in the
die. The top member or punch comprises a holder _D_ into which the
punch _E_ is screwed. This is bored out to fit an ejector _F_ which
ejects the forging as the ram of the press ascends. Punch _E_ and
stripper or ejector _F_ are made from high-speed steel, hardened. _G_
shows the cast blank and _H_ the completed forging.

[Illustration: Fig. 3. Tools used for forging Brass Plug]


=Forging Brass Plugs.=--The brass plug shown in Fig. 3 is used as a
temporary cap for the shrapnel to protect it during transportation. It
remains in the fuse socket until the shrapnel shell reaches the field
of operations, when it is removed and replaced by the timing fuse.
This member is made from a special forgeable alloy casting 2 inches
in diameter by ⁷⁄₈ inch thick and is cast in sand molds in a similar
manner to the fuse socket. It is also composed of the same constituents
as the socket and is forged in the same type of press. The construction
of the tools, however, varies somewhat from that of the tools used in
making the socket, as will be seen upon reference to Figs. 3 and 4. The
tools for the plug comprise a lower die _A_ carrying a combined ejector
and forming die _B_. Inserted in this lower forming die is a secondary
ejector _C_ which is operated by plunger _D_. The upper member of this
forging tool consists of a punch-holder _E_ carrying forming punch _F_
which is counterbored to receive an ejector ring _G_. Passing down
through the center of punch _F_ is a center-punch _H_ that is made
in two parts. The lower member is made of high-speed steel, hardened,
whereas the upper portion is ordinary carbon steel. This center-punch
is operated to eject the forging by a plunger _I_ on the up-stroke
of the press through the action of three pins _J_ coming in contact
with the flange on punch _H_. _K_ shows the rough casting and _L_ the
completed forging.

[Illustration: Fig. 4. Diagram showing Construction of Tools for
forging Brass Plug]


=Tooling for Machining Brass Socket.=--The New Britain automatic
chucking machine, referred to in the following, consists essentially of
a multiple-chuck turret with capacity for holding five or six pieces of
work, acted upon simultaneously by four or five tool-holding spindles.
The sequence of operations is similar to that of a multiple-spindle
screw machine. A finished piece is removed and a rough blank inserted
at each indexing. The machine is not idle while chucking, there being
one more chuck than spindles.

[Illustration: Fig. 5. Diagram showing First Series of Operations on
Fuse Socket on the New Britain Automatic Chucking Machine]

The shrapnel socket which, as previously explained, is made from a
brass casting and pressed into rough shape, is machined in two settings
in the New Britain No. 24 chucking machine. This machine has four
spindles, and at the first spindle position, as shown in Fig. 5, reamer
_A_ cleans out the hole in the pressed brass blank, counterbore _B_
cleans out the inside, and tool _C_ faces the end. At the second
spindle position, reamer _D_ finishes the central hole, counterbore _E_
faces the bottom, and tool _F_ chamfers the hole.

The under-cutting preparatory to threading is done at the third spindle
position. The operation is performed with tool _G_ working on the
cross-cutting head _H_. When the pressed blank is fed in and reaches
stop _I_, it commences to push the housing _H_ of the cross-cutting
head backward. A pair of stationary fingers _J_ operate in oblique
slots in the housing _H_, and as the housing presses down on these
fingers, the motion gives a cross movement to the under-cutting tool
_G_ and its arbor _K_. In this manner, the under-cutting of the piece
is performed. The fourth spindle operation is simply that of tapping
the threaded interior with a tap _L_.

[Illustration: Fig. 6. Diagram Illustrating Second Series of Operations
on Fuse Socket on New Britain Automatic Chucking Machine]


=Second Operation on Shrapnel Socket.=--Fig. 6 shows the order of
operations performed on the shrapnel socket at the second chucking, the
work being screwed on threaded arbors. At the first spindle position,
pilot _A_ engages the central hole, while tool _B_ turns the external
diameter, tool _C_ chamfers the corner, tool _D_ turns the thread
diameter, tool _E_ faces the shoulder, and counterbore _F_ finish-forms
the nose of the piece. At the second position, these same surfaces
are machined with finishing tools of the same design as those just
described.

At the third spindle position, the shoulder at the end of the threaded
section is under-cut. This is done by a cross-cutting head, similar to
that shown in Fig. 5 and carrying the cutter _G_. At the fourth spindle
position, the final operation--threading--is performed with die _H_.

[Illustration: Fig. 7. First Series of Operations on Fuse Body on No.
73 Seven-spindle New Britain Automatic Chucking Machine]


=Machining Fuse Bodies.=--In Fig. 7 is illustrated an interesting
tooling set-up for machining a fuse body. This is done on the No. 73
seven-spindle New Britain automatic chucking machine. The operations in
this set-up are performed on one end only of the fuse body. Strictly
speaking, this is a seven-spindle machine, but the first four spindles
carry internal spindles running at high speed that co-operate with
the external spindles in machining the work, making this virtually
an eleven-spindle machine. At the first spindle position, the broad
face and stem are machined with cutters _A_ of hollow-mill type, and
centering tool _B_, carried in the inner spindle, centers the work for
drilling.

In the second spindle position, tools _C_ bevel the external diameter
of the flange at the same time that drill _D_ is producing the hole
in the stem. In the third spindle position, roll _D_ supports the
work against the thrust of beveling tool _E_, and the small drill _F_
held in the internal spindle deepens the hole. At the fourth spindle
position, the external spindle carries a hollow-mill _G_ that finishes
the stem diameter, and a counterbore _H_ is carried in the internal
spindle to machine the central hole.

[Illustration: Fig. 8. Machining a Shrapnel Head on the New Britain No.
24 Automatic Chucking Machine]

A cross-cutting head in the fifth spindle position carries a circular
tool _I_ that machines on both sides of the section subsequently to be
threaded, and while this operation is being performed the pilot _J_
steadies the work as well as the tool-holder. In the sixth spindle
position, the small hole is threaded with tap _K_, and the exterior
is threaded with a die, tap and die being of different pitches. In
the seventh spindle position, a holder carries the forming tool _M_
for cutting grooves in the face of the flange, and the same spindle
carries a reamer _N_ that finishes the hole in the stem.

[Illustration: Fig. 9. First Series of Operations on Shrapnel Head on
the New Britain Automatic Chucking Machine]

[Illustration: Fig. 10. Second Series of Operations on Shrapnel Head on
the New Britain Automatic Chucking Machine]


=Machining Steel Shrapnel Heads.=--Heads for shrapnel shells made from
cold-drawn steel stampings are machined in two settings on a No. 24
New Britain automatic chucking machine of the four-spindle type, shown
in Fig. 8. This piece, shown in Fig. 9 in its sequence of operations,
is especially difficult to machine on account of the stringy nature
of the metal. The work is held for the first chucking with the small
end out, and in the first spindle position the facing on the end is
distributed between tools _A_ and _B_, while counterbore _C_ roughs out
and chamfers the hole. In the second spindle position, tool _D_ faces
the end, and counterbore _E_ finishes the hole. A cross-cutting head
of a type similar to that previously described is carried in the third
spindle position. This retains a tool _F_ which produces an annular
groove in the nose of the head, the work being supported with pilot
_G_. The fourth and last operation consists in threading the hole with
the tap _H_.

[Illustration: Fig. 11. Diagram showing Tooling Set-up for machining
Fuse Nose on New Britain Automatic Chucking Machine]

[Illustration: Fig. 12. Machining Brass Fuse Socket on 3¹⁄₄-inch
“Gridley” Automatic Turret Lathe--First and Second Series of Operations]


=Second Series of Operations on Shrapnel Heads.=--The set-up for the
series of operations performed at the second chucking is shown in Fig.
10, the work being held on threaded arbors. In the first spindle
position, tools _A_ and _B_ face the shoulder, and counterbore _C_
machines a seat in the inner flange. In the second spindle position,
counterbore _D_ finishes the part roughed out by _C_ in the previous
operation, tool _E_ faces the end, and tool _F_ chamfers the inner
edge. In the third position, a cross-cutting attachment carrying
external cutting tool _G_ is utilized for recessing the external
diameter next to the shoulder. The threading on the external diameter
is accomplished with the die _H_ in the fourth spindle position.


=Machining Shrapnel Fuse Noses.=--The time fuse nose for a shrapnel
shell, which is made from a brass forging, is machined as shown in Fig.
11 on a No 33 New Britain automatic chucking machine at one setting. In
this case, an extra spindle designated as No. 0 is added to the machine
for equalizing or properly locating the forging in the chuck when it
is being tightened. At the first spindle position, tool _A_ takes a
cut from the external diameter, tool _B_ cuts an annular recess in the
face, and counterbore _C_ roughs out the center portion. In the second
spindle position, the same operations are performed with finishing
tools. In the third spindle position, a cross-cutting head carries a
recessing tool _D_ that forms a recess back of the tapped portion. The
hole is then tapped in the fourth spindle position, and in the fifth
spindle position a special counterbore _F_ takes a light finishing cut
from all the surfaces previously machined. The external surfaces of the
fuse nose are machined on a turret lathe.

[Illustration: Fig. 13. Diagram Illustrating First and Second Series of
Operations on Fuse Body on “Gridley” Automatic]


=Machining Shrapnel Fuse Parts on “Gridley” Automatics.=--The machining
of fuse parts for the British shrapnel shell on “Gridley” single- and
multiple-spindle automatics, made by the Windsor Machine Co., Windsor,
Vt., forms the basis of several interesting tooling equipments. A
number of the parts are machined from hot-pressed brass forgings, so
that they must be handled separately. The fuse socket, as has been
previously described, is made from a brass forging and is machined
complete in two operations on a 3¹⁄₄-inch “Gridley” automatic turret
lathe of the single-spindle type. The manner in which the work is
loaded in the chuck and held for the first series of operations is
shown at _A_ in Fig. 12. The rough blank _a_ is first placed over the
spring fingers _b_, which are held in a holder clamped in the turret,
but are free to rotate. When the work is pushed into the chuck, it
forces back spring-ejecting stud _c_, which, as soon as the pressure of
the chuck is released, ejects the work.

As the loading device operates on the first slide of the turret, the
first machining operation takes place on the second slide. This is
a comparatively simple operation and consists in boring the central
recess with a tool _d_ and chamfering with tool _e_. The turret is then
indexed, bringing the internal necking tool _f_ into position. This is
held in a holder and is operated by the forward motion of the forming
slide. Following this, tap _g_ is brought into position to thread
the recess in the socket. The operation of the turret is now stopped
automatically until the operator loads a new piece in the chuck. The
tapping is done with the spindle running in the forward direction on
slow speed. After the hole has been tapped, the spindle is reversed and
operated at a higher speed. The spindle continues to run backward for
loading, and is still running backward, but slowed down, at the time
of the second operation. It is for this reason that the boring tool
_d_ operates on the reverse side of the hole, and tool _e_ is mounted
upside down. At the third operation, the spindle is still running
backward but is speeded to its highest speed while the internal necking
is done with the tool on the reverse side of the hole.


=Second Operation on Fuse Socket.=--The method of holding the fuse
socket for performing the second operation on the 3¹⁄₄-inch “Gridley”
single-spindle automatic turret lathe is shown at _B_ in Fig. 12. The
socket _h_, which has now been threaded, is screwed onto the body of
special arbor _i_, fitting in sleeve _j_ that is gripped by the spring
collet. On the reduced end of arbor _i_ is a nut which serves to clamp
the work up against the face of sleeve _j_. The method of using this
arbor is as follows:

To chuck the work, sleeve _j_ and its auxiliary members are removed
from the spring collet, and the work is screwed onto the nose of
arbor _i_, the position of which is locked by means of a nut on the
stem of the arbor. The entire arbor is then replaced in the collet and
the machining operations performed on the work. This type of arbor is
necessary because of the heavy cutting with the wide forming tool which
would tighten the piece on the threaded nose to such an extent that
it could not be removed when finished. With this device, it is only
necessary to hold the square end of arbor _i_ in a vise, and loosen
the work by relieving the nut on the arbor. In order to facilitate the
work, two arbors of this type are provided with each of the machines
employed.

[Illustration: Fig. 14. Section through a “Gridley” 3¹⁄₄-inch Automatic
Turret Lathe Spindle showing Method of chucking Shrapnel Fuse Body]

The operations performed in the first position consist in forming
the external diameters with tool _k_, facing with the side tool, and
drilling with drill _m_. The second turret face is now skipped and the
third brought into position, presenting self-opening die _n_ which
threads the work. At the fourth indexing of the turret slide, the hole
is reamed with reamer _o_ and tool _p_ chamfers the face, completing
the work. The forming done at the first indexing of the turret slide is
performed on slow speed; the spindle speed, however, changes to high at
the third position and back to slow just before the fourth position.


=Machining the Fuse Body.=--The fuse body is made from a hot-pressed
brass blank, and is machined in two chuckings in “Gridley”
multiple-spindle automatics. The first series of operations is
performed in a “Gridley” 1¹⁄₄-inch multiple-spindle automatic in the
order shown to the left in Fig. 13. The work is loaded in the chuck
by hand. Forming tool _A_ now advances and rough-forms the outer
diameter, whereas flat drill _B_ and trepanning tool _C_ combine to
drill the central hole and trepan the narrow channel. At the second
spindle position, tool _D_ finish-forms and necks the outer surface,
while tool _E_ counterbores the surfaces of the recess. Die _F_ at the
third spindle position now threads the body, and at the fourth spindle
position forming tool _G_ turns down the outer end of the thread while
a floating trepanning tool _H_ finishes the counterbored and trepanned
surfaces. It should be mentioned here that the hot-pressing of this
brass part makes it extremely difficult to machine, so that the edges
of the tools dull rapidly.


=Second Series of Operations on Fuse Body.=--The method of holding the
fuse body while the second series of operations is being performed
is shown in Fig. 14. The work-spindles _A_ of the machine are fitted
with special nose-pieces _B_, the inner surface of which is chamfered
to receive the spring collet _C_, which is threaded to the end of
draw-back rod _D_. The work is not gripped directly by the spring
collet, but is first screwed into a special bushing _E_, having thin
walls as shown. This bushing is not split but springs sufficiently
to permit it to be closed in on the work and released when the
collet pressure is removed. A flange _G_ attached to the end of the
spindle nose serves as a stop for the work and a gaging point for the
operations. The regular collet closing mechanism is used, but as may be
seen in the left-hand end, the finger holders are reversed. When the
clutch ring _H_ is pushed forward by the chuck-closer gripping fingers
_I_ swivel and draw rod _D_ backward through contact with flange _J_.
When the clutch ring _H_ is moved backward, the gripping fingers
release rod _D_, relieving the pressure of the collet on bushing _E_
and the work.

[Illustration: Fig. 15. Diagram illustrating Set-up for machining
Timing Train Rings on “Gridley” Automatic]

Referring again to Fig. 13, the second series of operations on the
fuse body is shown to the right of the illustration. At the first
spindle position, forming tool _I_ advances and forms the exterior
diameters, while drill _J_ drills the hole in the end. At the second
spindle position, the rear part of the work is supported by a roll
back-rest, while the regular turner _K_ takes a cut across and chamfers
the shoulder. At the same time counterbore _L_ comes in, cleans up
the drilled hole and faces the bottom. At the third spindle position,
the diameter _M_ is threaded with a plain die. At the fourth spindle
position, a tool _N_ operated from the turret cuts a series of
concentric grooves in the flange of the fuse body. The grooving tool is
cut away to clear the forming tool _O_ which takes a light cut over the
grooved face, finishing the body as illustrated.


=Machining the Stationary Timing Train Ring.=--The machining operations
on the stationary timing train ring are shown to the left in Fig.
15, and as can be seen are of a comparatively simple nature. This
fuse part is made from a Tobin bronze bar in a 2³⁄₈-inch “Gridley”
multiple-spindle automatic. At the first spindle position, a drill held
on the turret drills the hole, and a forming tool on the cross-slide
forms it to shape and breaks it down for the cut-off tool. At the
second spindle position, the piece is reamed, and at the third position
it is faced off with an under-cutting tool. In the fourth spindle
position, not shown, the finished piece is cut off, and the stock is
fed out.


=Machining the Graduated Timing Train Ring.=--The machining operations
on the graduated timing train ring are almost identical with the
stationary ring and are shown diagrammatically to the right in Fig.
15. This part is also made from a bar of Tobin bronze in a 2³⁄₈-inch
“Gridley” multiple-spindle automatic. The only difference in the
operations on this part is in the use of a combination floating
counterbore, and facing tool provided with a roller pilot.

[Illustration: Fig. 16. Diagram Illustrating Set-ups for machining
Closing Cap and Bottom Closing Screw on “Gridley” 1³⁄₄-inch
Multiple-spindle Automatic]


=Machining the Closing Cap and Bottom Closing Screw.=--The closing cap
and bottom closing screw for the shrapnel timing fuse are made from
brass rod with a comparatively simple tool set-up as shown in Fig. 16.
The machine used is a 1³⁄₄-inch “Gridley” multiple-spindle automatic.
The machining operations on the closing cap are shown to the left in
the illustration, and consist in drilling, counterboring, forming,
threading, and cutting off. The operations on the bottom closing
screw, shown to the right of this illustration, are counterboring,
forming, recessing, threading, and cutting off.

[Illustration: Fig. 17. Method of machining Fuse Hammer on a No.
2 Model G Brown & Sharpe Automatic Screw Machine equipped with an
Eight-hole Turret]


=Making Fuse Parts on Brown & Sharpe Automatic and Hand Screw
Machines.=--A brief description of two of the many interesting set-ups
on Brown & Sharpe automatic and hand screw machines for making timing
fuse parts is given in the following. Timing fuse parts are made from
several different materials. The screws and other small members as a
rule are made from brass rod, whereas the parts such as the capsules,
primer cups, etc., are made from sheet brass. Other members, such as
the fuse body or stem, are made from different alloys and metals such
as copper, copper aluminum, aluminum, etc.

[Illustration: Fig. 18. Diagram Illustrating Method of Machining a Fuse
Nut on a No. 6 Brown & Sharpe Hand Screw Machine]


=Set-up for Making Fuse Hammers.=--The method of making a fuse hammer
on a No. 2 Model G Brown & Sharpe automatic screw machine provided
with a special eight-hole turret is shown diagrammatically in Fig.
17. This part is made from ⁷⁄₈-inch round brass rod and is finished
complete in the screw machine. First, the stock is fed out to the stop
in the turret. Second, the end is centered and faced with tools held
in tool-holder _A_. The body is then formed with a circular tool _B_
working from the front cross-slide; at the same time the turret is
revolved, bringing tap drill _C_ into operation. The forming tool is
working at the same time as the drills. The turret is again revolved
and drill _D_ for finishing the middle hole is brought in and completes
its operation. At the next index of the turret, drill _E_ finishes the
bottom hole. The turret is now indexed and a recessing tool-holder
carrying tool _F_ advances and is brought into operation to recess the
work by a pusher on the cross-slide. The turret is again indexed and
a reamer _G_ is advanced to bottom and ream the holes. Upon the next
index of the turret, tap _H_ threads the work, which is finally cut off
with circular tool _I_. The stock is rotated at 973 R. P. M. forward
and backward for drilling and turning, and at 421 R. P. M. forward for
threading. The stock is cut off rotating backward. The surface speed
for the forming tools is 220 feet per minute and 31 feet per minute for
the tap.


=Tool Set-up for Making Fuse Nut.=--The fuse nut on the Russian timing
fuse is made from 1⁷⁄₈-inch round brass rod in a No. 6 wire-feed Brown
& Sharpe hand screw machine as shown in Fig. 18. First the stock is
fed out to length, being gaged by a stop in a vertical slide, which is
held in the turret. The turret is then indexed and drill _A_ drills the
large hole. The turret is now revolved and the combination drill _B_ is
advanced. The turret is again revolved and counterbore _C_ faces and
counterbores the work. Upon the next index of the turret, a vertical
slide tool-holder carrying recessing tool _D_ is advanced. This
tool-holder is operated by a handle attached to the holder. The turret
is again indexed and tap _E_ threads the work. After this the turret is
indexed and the work is recessed with a tool-holder _F_ carrying two
cutters which balance each other in cutting. The seventh operation is
performed from both the front and rear cross-slides with tools _G_ and
_H_. The eighth operation is cutting off. This is performed with a
special vertical slide tool-holder held in the turret and operated by
a handle. The stock for these operations is rotated at 352 R. P. M.,
giving a surface speed for the forming tools of 180 feet per minute and
66 feet per minute for the tap.


=Making Fuse Parts on Hand Screw Machines.=--The demand for shrapnel
fuse parts has been so great that time has not been taken in all
cases to tool up automatic screw machines before production has been
started. In order to get parts out quickly while automatic machines
are being tooled up, hand screw machines have been made use of. These
machines are also used to a large extent on small orders and to help
out production in general. Fig. 19 shows an F. E. Wells & Son Co. hand
screw machine working on shrapnel fuse parts. The capacity of this
machine is for ⁷⁄₈-inch diameter rod and it will tap or drill ¹⁄₂ inch
diameter. Shrapnel fuse parts are produced on this machine at the rate
of from 25 to 100 pieces per hour.

[Illustration: Fig. 19. Machining Fuse Parts on F. E. Wells & Son’s
Hand Screw Machine]

[Illustration: Fig. 20. Drilling Percussion Primers on a Leland-Gifford
Ball Bearing Sensitive Drilling Machine]


=Drilling Percussion Primers for Fuses.=--The percussion primer, used
in the American combination fuse shown in Fig. 3, Chapter I, is made
in a Brown & Sharpe automatic screw machine from brass rod in two
operations. Following the screw machine operations, four holes about
¹⁄₃₂ inch in diameter are drilled through this bushing, employing a
special “snap index” jig in a high-speed ball-bearing drilling machine
made by the Leland-Gifford Co. of Worcester, Mass. (See Fig. 20.) The
extremely small size of this part makes it difficult to handle, so
the jig was designed with a special loading arm to facilitate rapid
handling. The jig consists of a platform base bolted to the table of
the drilling machine. Upon this is the index ring, which is turned
by handles _J_ and indexed for the four drilling positions by spring
plunger _I_. The center of rotation is in the center of the four holes
in the part. _B_ is the loading lever, with a nest _A_ at the end into
which the work is slipped. This lever swings on stud _C_. The work is
located in the swinging arm _B_ when it is in the position shown in the
illustration, with the arm _B_ resting against stop _D_. The arm is
then swung under the drill until it reaches stop _E_. It is maintained
in this position by spring plunger _H_ that bears against lever _F_,
fulcrumed on stud _G_. The side of this lever bears against the work
and holds it firmly while the drilling is proceeding. The drill is
guided by four bushings in plate _L_, mounted on the index ring. The
operation consists in rotating the index ring to the four stations for
drilling the respective holes. By means of this quick-indexing ring,
and the high speed at which the Leland-Gifford drilling machine runs,
it is possible to drill as many as 6000 pieces, or 24,000 holes in ten
hours.

[Illustration: Fig. 21. Drilling Fuse Plugs on “Avey” Drilling Machine]

[Illustration: Fig. 22. Graduating Timing Fuse Rings on Dwight-Slate
Marking Machine]


=Drilling Timing Fuse Plugs.=--An application of a regular No. ¹⁄₂
“Avey” drilling machine, built by the Cincinnati Pulley Machinery Co.,
Cincinnati, Ohio, to the drilling of brass timing fuse plugs is shown
in Fig. 21. The requirements are to drill three No. 55 (0.052 inch)
holes through the dome of the plug; a number of pieces are shown on
the table of the machine. These three holes practically run together
at the inside of the dome, making it necessary to drill one hole at
a time. The fixture used for this purpose is of unique construction.
The body _A_ is made of an aluminum casting, whereas the operating
mechanism is of hardened tool steel. The drill spindle is operated by
a foot treadle, connection being secured through rod _B_, passing down
through the fixture and fastened to the spindle sleeve by the L-shaped
piece and yoke _C_. The work _E_ is held on a special work-spindle
located inside the fixture that is indexed one-third revolution through
the medium of rod _B_ upon the raising of the drill spindle sleeve.
The work holding-down and ejecting mechanism is supported in aluminum
bracket _F_. Attached to this bracket is a supporting arm for the lower
crank of lever _G_, which holds a segment gear. Bracket _D_ carries
the drill bushing.

After drilling the third hole, the operator depresses lever _G_,
rotating the segment gear meshing in rack teeth in rod _H_, which
lifts the latter up to eject the work and at the same time through
a connection, not shown, raises the holding-down rod. The ejector,
not shown, which is spring-controlled, returns to a neutral position
immediately upon the ejection of the work, while the holding-down
rod is still raised. The work, after being discharged, falls into a
chute and is carried to the rear of the machine. The operation of this
fixture is rapid, the production being from 9000 to 10,000 pieces in
ten hours.


=Graduating Fuse Timing Ring.=--As has been previously stated, the
adjustable ring on the timing fuse is graduated in seconds, starting
at zero and running to twenty-one seconds. As shown in Fig. 22, the
graduating of this timing ring is performed in the Dwight-Slate marking
machine built by Noble & Westbrook, Hartford, Conn. The main arbor of
the machine carries the stamping roll _A_ and is turned by the handle
shown. The timing ring to be graduated and marked is held at _B_. The
two gears _C_ prevent the stamp from “creeping” ahead or slipping
on the work. The work-holding arbor, as shown, is held in a bracket
and is raised to the stamp roll by pressure on the foot treadle. Two
operations are required for stamping and graduating the timing ring.
The first is marking the graduations and the second is putting on the
figures.




CHAPTER VI

MAKING SHRAPNEL CARTRIDGE CASES


The brass cartridge case that contains the powder charge for propelling
the shrapnel shell from the bore of the quick-firing gun is drawn up
from a blank of sheet brass. The number of operations necessary to
complete the case depends on its size and the method of handling. Some
shell manufacturers prefer to do more or less drawing at one operation,
but in all cases the sequence of operations is practically the same.
The material used for shrapnel cartridge cases generally consists of
a composition of 2 parts copper and 1 part zinc. This alloy has been
found to possess the best physical qualities, that is, great tensile
strength and a high percentage of elongation when properly annealed.
The drawing operations through which the cartridge case passes increase
the hardness, and the ductility of the metal is restored by annealing.
The annealing temperature in most cases is from 1150 to 1200 degrees F.
On reaching this temperature, the work is either cooled off in water or
allowed to cool off gradually, as the speed of cooling does not affect
its physical qualities. In the following, two methods of handling the
various operations will be described.


=Method of Making Cartridge Cases.=--Figs. 1 and 2 show the sequence
of operations--blanking, cupping, re-drawing, indenting, trimming,
heading, and tapering, as advocated by the Waterbury Farrel Foundry &
Machine Co., Waterbury, Conn., for making cartridge cases for 18-pound
shrapnel. The first operation consists in cutting out a blank from
³⁄₈-inch sheet brass 6¹⁄₄ inches in diameter. The next operation is
cupping. This is handled in a short-stroke geared straight-sided press.
Before re-drawing, the cup is annealed, and the third operation, which
is handled in a longer stroke press, is then performed. Annealing
follows this operation, and then the fourth drawing or second
re-drawing operation is performed. This consists in reducing the
fillets slightly at the corners, decreasing the diameter of the cup to
4¹⁄₈ inches and increasing its length to 4¹⁄₂ inches. The dimensions
given here are approximate.

[Illustration: Figs. 1. and 2. Operations in making an “18-pound” Cartridge
Case]

=Indenting Operations.=--The fifth operation or first indenting
operation, which consists in indenting the bottom, is handled in a
press similar to that used for the cupping and re-drawing operations.
This shortens the length of the case by ¹⁄₄ inch and forces the
indentation about half way through the thickness of the stock. The
second indenting is then accomplished. This again shortens the case by
an additional ¹⁄₄ inch and squares up the corners. The case, without
annealing, is now passed through the third re-drawing, or seventh,
operation, reducing its diameter to 4 inches and increasing its length
to 5¹⁄₂ inches. It is annealed after this operation, and is then drawn
to a shape 8 inches in length by 3⁷⁄₈ inches in diameter, and the
wall decreased in thickness to ¹⁄₁₆ inch. The case is then annealed
and passes through the fifth re-drawing operation. The machine used
for handling the third, fourth and fifth re-draws is a long-stroke
straight-sided rack-and-pinion press. After the fifth re-drawing, or
ninth, operation, the case is trimmed and about two inches cut off
the end. This leaves the case in better condition for the succeeding
operations. The trimming machine is of the horizontal type.


=Final Re-drawing Operations.=--The sixth re-drawing, or eleventh,
operation is performed in a horizontal drawing press of the hydraulic
type provided with automatic reversing valves. This operation increases
the length of the case to 13¹⁄₄ inches and reduces its diameter to 3³⁄₄
inches. After this operation, the case is annealed and then 1¹⁄₄ inch
is trimmed off the open end. The thirteenth and fourteenth operations
consist in heading the case. These are practically of the same nature,
and combine to form the head of the case as shown in the illustration.
The heading operations each reduce the length of the case ¹⁄₄ inch,
and are performed in a 1000-ton hydraulic heading press operated by a
geared compound power pump and having a working pressure of 5600 pounds
per square inch on the ram. After heading, the case is annealed and the
fifteenth operation, which consists of tapering, is performed. The
first tapering, or fifteenth, operation reduces the mouth of the case
to 3⁹⁄₁₆ inches in diameter and gradually tapers it for a distance of
5⁷⁄₈ inches--half the length. The case is then annealed, pickled and
washed, and a second tapering operation is performed. This reduces the
mouth of the case to 3³⁄₈ inches and tapers it completely to the head.
The case is not annealed after the last tapering operation, but ¹⁄₄
inch is trimmed off the end.

The various operations through which a cartridge case passes in drawing
and forming to the correct length having been described, attention will
now be given to the type of tools used for this purpose. These tools
have been designed and built by the Ferracute Machine Co., Bridgeton,
N. J., and are used with its presses for making cases for 3-inch
projectiles.


=Cupping and First Series of Re-drawing Tools.=--The cutting out of
the blank is frequently omitted because the specified thickness and
size can be furnished by the mill. Before cupping, the dies and blanks
are well greased, as this assists in drawing. Olive oil or soapy water
is used, depending on the stage at which the drawing operations have
arrived. The first cupping operation is accomplished with a punch and
die as shown at _A_ in Fig. 3. This operation is accomplished in a
Ferracute 100-ton ram press equipped with a dial feed. The die consists
of a hardened ring of tempered steel having an interior shape similar
to a truncated cone. The punch is slightly tapered on the lower end and
has an air vent hole drilled up through it to facilitate the drawing
and produce a cup free from wrinkles.

[Illustration: Fig. 3. Tools for drawing a 3-inch Shrapnel Cartridge
Case--Ferracute Machine Co.’s Method]

The second operation, or first re-drawing operation, is shown at _B_.
Here the type of die used differs somewhat from that shown at _A_, in
that the drawing angle is 15 instead of 45 degrees. The cup, after this
operation, is reduced in diameter to 3.877 inches and is 2⁷⁄₈ inches
long. After the first cupping operation, the case is annealed.

The second re-drawing operation is accomplished as shown at _C_. The
die in this case is the same as at _B_, as is also the punch, except
for an increase in the taper and change in shape on the end. The
object of this, of course, is to keep the case thick at the head but
reduce the walls further up along the section. The case, after this
operation, is also drawn out to a length sufficient to necessitate
using a stripping device for removing it from the punch. This is
accomplished by six spring-operated stripper pins as shown, which
slip over the top edge of the case as it is forced through the die,
stripping it from the punch. The cup now passes through the third
annealing operation and is ready for the third re-draw, shown at
_D_. The press used for performing this operation is similar to that
described, and the die and punch is similar in construction to that
shown at _C_.


=Final Re-drawing Operations.=--For the final re-drawing operations,
horizontal double-ended screw presses instead of the horizontal
hydraulic presses formerly used are employed. Horizontal presses are
used because the length to which the cartridge case is drawn after
the third re-draw is such that it exceeds the stroke of the vertical
presses. The cartridge case, after each drawing operation, is annealed;
_E_ in Fig. 3 shows the fourth re-drawing tools, which are handled in a
horizontal screw press. The die used is similar in shape to that shown
at _D_, but the holder in which it is held differs, of course, owing
to the difference in the type of press used. The stripping arrangement
for removing the case from the punch is also of a different type. In
this case five spring-operated stripper pins are held in a holder which
is free to oscillate within certain limits in the block in which it
is retained. The reason for having this oscillating stripper is that
it accommodates itself to the irregular shape on the end of the case
and gives practically a constant pressure all around the circumference
of the case, assisting in removing it from the punch. The case is now
annealed and is finish-drawn as shown at _F_. Here the same type of
die, stripper arrangement, etc., is used as that shown at _E_. The case
in the fifth re-drawing operation is 14³⁄₈ inches long by 3.186 inches
outside diameter.


=Annealing and Washing Cartridge Cases.=--As was previously stated,
the cartridge case, after practically every re-drawing operation,
is annealed, being subjected to a temperature of about 1150 to 1200
degrees F. and then allowed to cool off or dipped in water which, of
course, forms a scale on the surface of the case. This must be removed
before any subsequent operations can take place. Several different
solutions are used for this purpose, but a common one comprises the
following: Sulphuric acid diluted with water to a strength of 1 to 4.
This pickling solution is held in lead-lined wooden troughs and the
case is allowed to remain in the bath varying from eight to fifteen
minutes, according to the strength of the solution. The cases are then
washed in lead-lined wooden troughs through which a stream of water is
circulated to remove all traces of the acid.

[Illustration: Fig. 4. Fixture for testing Hardness of Cartridge Cases
with Shore Scleroscope]


=Testing Hardness of Cartridge Cases.=--The hardness of a cartridge
case must conform to a certain standard. When too soft, a permanent
set will occur from the pressure of the firing charge and the case
will stick in the breech of the gun. When the hardness is too high for
a given composition of brass, it is too brittle and will split, or
the head may blow off. There is, therefore, a certain hardness which
must be adhered to as closely as possible. Some manufacturers hold the
standard to within 20 to 25 on the body walls and reject cases striking
15 as being too soft, and 30 to 35 as being too hard.

Owing to the thinness of the walls of the case, it is impossible to
take a reading without rigidly supporting it, and for this purpose the
Shore Instrument & Mfg. Co., 551-557 West 22nd St., New York City,
has devised a special fixture as indicated in Fig. 4. This comprises
a bracket _A_ held in an ordinary vise, to which is fastened an anvil
plug _B_, as indicated. In order to hold the case tightly against the
anvil plug, a spring _C_, fastened to the bracket _A_, is also fastened
to a yoke _D_ surrounding the case. A rod attached to the yoke and to
a foot treadle furnishes a means of drawing the yoke down to hold the
case in contact with the plug. The anvil plug provides the weight or
inertia to resist the impact of the drop-hammer of the scleroscope, but
in order to be sure that there is proper contact of the case with the
plug a rubber cushion _E_ is provided between the pressure ring or yoke
and the brass case.

[Illustration: Fig. 5. Special Shrapnel Case Trimming, Facing, and
Chamfering Machine]

[Illustration: Fig. 6. Sequence of Operations performed on Cartridge
Case in Machine shown in Fig. 5]


=Machining Shrapnel Cartridge Cases.=--The Bullard Machine Tool Co.,
Bridgeport, Conn., has designed and built a number of special machines
for performing the machining work on the head and mouth ends of brass
cartridge cases. This machine, as will be seen from Fig. 5, is of the
hand turret machine type, designed to work on the case from both ends.
In this machine the brass case is chucked in the center of an extremely
large spindle, and worked on from the head end with four sets of turret
tools and two sets of cross-slide tools, while the mouth end is bored
and trimmed with tools held on a carriage located on the back facing
bar. The drive for the work chuck spindle is over a 16-inch pulley
with a 3-inch belt. The pull of the belt is not taken directly on
the spindle, but on a special pulley bearing 7³⁄₈ inches in diameter
and 5 inches in width. The spindle itself is supported in bearings 9
inches in length and 5⁷⁄₈ inches in diameter. As previously mentioned,
the spindle is hollow so that any type of shrapnel cartridge case up
to 4¹⁄₄ inches in diameter and from 10 to 18 inches in length can be
machined.

[Illustration: Fig. 7. Set-up showing First Operation on Cartridge Case
Head]

From the construction of the machine in Fig. 5 it will be seen that the
front end of the spindle carries a large three-jaw chuck of special
design. These jaws catch the cartridge case just under the head and
revolve it for machining. The case is supported internally by a tubular
arbor which also acts as a stop and is attached to a rod extending to
the rear bracket where it is backed up by a spring. The front end of
this tubular support or stop is provided with a thrust ball-bearing so
that the case can be loaded in the chuck while the spindle is running.
When the chuck operating lever is manipulated to close the chuck jaws
on the work, it first draws back the rod mentioned through the medium
of a tie-rod and the rear bracket to a positive stop, and then closes
the jaws on the work. The cartridge case is put in and removed from the
chuck with the turret indexed between stations to give the required
space.

[Illustration: Fig. 8. Set-up showing Fourth Operation on Cartridge
Case Head]

[Illustration: Fig. 9. Set-up showing Operations on Mouth End of Case]

The back boring and trimming head is held on a hollow spindle through
the center of which the rod passes. This spindle is provided with rack
teeth on its top surface which engage with a pinion located in the
extension bracket and operated by a handle. The forward position of the
boring and trimming head is governed by a stop-collar.

[Illustration: Fig. 10. Set-up showing Sixth Operation on Head End of
Case]

[Illustration: Fig. 11. Set-up showing Seventh Operation on Head End of
Case]


=Sequence of Machining Operations on Cartridge Case.=--The sequence
of machining operations performed on the cartridge case in this
machine is shown diagrammatically in Fig. 6, and also in Figs. 7 to 11,
inclusive. Referring to Figs. 6 and 7, the first operation consists
in rough-drilling and counterboring the hole in the head of the case
with combination tool _A_. The second operation (see Fig. 6) consists
in facing, trimming and chamfering the head with tools _B_, _C_, and
_D_ held on the front of the cross-slide. The third operation is to
finish chamfering and facing the head of the case with tool _E_ on the
rear of the cross-slide. The fourth operation consists in under-cutting
the primer seat with the tool _F_ which works on a turret slide and is
operated by lever _G_ as shown in Fig. 8.

[Illustration: Fig. 12. Diagram showing Method of chucking a French
75-millimeter Cartridge Case on a Potter & Johnston Chucking Machine]

[Illustration: Fig. 13. Diagram illustrating Machining Operations on
French Cartridge Case on Potter & Johnston Machine]

The following operations are now performed on the mouth or open end of
the cartridge case as shown in Figs. 6 and 9, with the spindle running
at the same speed--500 R. P. M.--as that used for the first series of
operations. Two tools _H_ and _I_ are used. Tool _H_ bores the mouth
of the case for a distance of 1 inch, whereas tool _I_ trims off the
open end of the case and rounds the edges. The mouth of the case at the
rear end of the spindle is supported by a hardened bushing to prevent
it springing away from the action of the boring tool. The boring and
trimming tools are mounted in a special head _J_, Fig. 9, that is
operated back and forth by a handle _K_ through the medium of a rack
and pinion. The forward movement of this head, as previously explained,
is controlled by means of an adjustable collar _L_ screwed onto spindle
_M_.

[Illustration: Fig. 14. Tooling Set-up for Machining 18-pound Cartridge
Case]

The work-spindle is now slowed down and the following operations,
shown in Figs. 6, 10, and 11, are performed on the head end of the
case. The sixth operation is to finish-counterbore and ream the primer
pocket with tool _O_ held in an adjustable holder, whereas the seventh
operation is threading the primer pocket with collapsible tap _P_. The
chuck lever in Fig. 5 is now manipulated, first, releasing the grip of
the chuck jaws on the case and, second, advancing the rod to eject the
case sufficiently to enable it to be easily removed from the chuck. The
spindle is changed to the highest speed after the next case is put in.
In changing the work, it is not necessary to stop the spindle.

[Illustration: Fig. 15. Tool Set-up for Machining 18-pound Cartridge
Case]


=Machining Shrapnel Cartridge Cases on Potter & Johnston
Automatics.=--The cartridge case is made from sheet brass as previously
stated. It is practically formed to shape in drawing and heading
machines, but to secure the desired accuracy on the head and primer
pocket these surfaces are machined. The method of holding the French
75-millimeter case on a No. 5A Potter & Johnston automatic chucking and
turning machine for machining the head and primer pocket is shown in
Fig. 12. Here it will be seen that the cartridge case butts up against
a stop _B_ and fits over the tapered plug _C_, which steadies it. It
is held in place by an ordinary draw-in collet _D_. This is operated
by means of a lever _E_, fulcrumed to a bracket on the rear end of the
machine and operating a sliding clutch collar. The chuck is operated
through fingers which draw back the sliding sleeve to which it is
attached. These fingers operate against a spring at the rear of the
spindle which serve to open the collet.

The machining operations on the French shrapnel cartridge case are
handled in the manner illustrated in Fig. 13. The first operation is to
rough-drill the hole in the head. The turret is then indexed, bringing
in a roughing reamer which reams the hole previously drilled, whereas
the front cross-slide carries tool _B_ that faces the head and a
circular tool _C_ that rough-forms the external diameters of the head.

Upon the next indexing of the turret, the tool _D_ counterbores the
powder pocket and the circular forming tool _E_ finish-forms and
rough-chamfers the head. The last operation consists in finishing the
primer pocket with a taper reamer _F_.


=Machining the British Shrapnel Cartridge Case.=--The brass cartridge
case for the British shrapnel is more difficult to machine than the
French case, as reference to Figs. 14 and 15 will clearly show. The
machining operations are accomplished on a No. 5A Potter & Johnston
automatic chucking and turning machine having a five-sided turret. The
first operation is to drill the primer pocket hole with a three-step
drill _A_. The turret is now indexed and the surfaces previously
roughed out are finished with inserted-blade counterbore _B_. At the
same time, the head of the case is faced with a relieving tool _C_ held
on the cross-slide and rough-formed with circular tool _D_.

The turret, in being indexed to the third position, brings vertical
recessing tool _E_ into operation. This carries two cutters, one of
which recesses the primer pocket at the point where the thread is to
terminate, whereas the other removes the burr and faces the inner boss.
In the fourth operation, the smallest diameter of the primer pocket
is reamed and the largest diameter of the hole chamfered by tools
held in bar _F_. The rear cross-slide is advanced at the same time,
carrying the circular tool _G_ that finish-forms the head. The final
operation--threading--is performed with the “Geometric” collapsible tap
_H_.

DRAWING, HEADING AND MACHINING OPERATIONS ON “18-POUND” BRITISH
CARTRIDGE CASE

[Illustration]

  +-----------------------+-------+-------+-----------+---------------+
  |                       |  Dimensions   |           |               |
  |       Operation*      |    Inches     | Machine   |   Scleroscope |
  |                       |   A   |   B   | Used      |     Reading   |
  +-------+---------------+-------+-------+-----------+---------------+
  | 1     | Blanking      |       |       | Punch     |       15      |
  |       |               |       |       | Press     |               |
  |       |               |       |       |           |               |
  | 2(300)| Cupping       | 4.45  | 2.30  | Bulldozer | _a_, 15;      |
  |       |               |       |       |           | _b_, 50       |
  |       |               |       |       |           |               |
  | 3(300)| Annealing     |       |       |           |       15      |
  |       |               |       |       |           |               |
  | 4(300)| 1st Redrawing | 4.232 | 3.45  | Bulldozer | _a_, 15;      |
  |       |               |       |       |           | _b_, 50       |
  |       |               |       |       |           |               |
  | 5(300)| Annealing     |       |       |           |       15      |
  |       |               |       |       |           |               |
  | 6(300)| 2nd Redrawing | 4.081 | 4.6   | Bulldozer | _a_, 40;      |
  |       |               |       |       |           | _b_, 45       |
  |       |               |       |       |           |               |
  | 7(300)| Annealing     |       |       |           |       15      |
  |       |               |       |       |           |               |
  | 8(300)| 1st Indenting | 4.081 | 4.23  | Bulldozer | _a_, 18;      |
  |       |               |       |       |           | _b_, 15       |
  |       |               |       |       |           |               |
  | 9(300)| 3rd Redrawing | 3.952 | 6.25  | Bulldozer | _a_, 18;      |
  |       |               |       |       |           | _b_, 45       |
  |       |               |       |       |           |               |
  |10(300)| Annealing     |       |       |           | _a_, 13;      |
  |       |               |       |       |           | _b_, 15       |
  |       |               |       |       |           |               |
  |11(300)| 4th Redrawing | 3.844 | 7     | Bulldozer | _a_, 35;      |
  |       |               |       |       |           | _b_, 45       |
  |       |               |       |       |           |               |
  |12(300)| Annealing     |       |       |           |       15      |
  |       |               |       |       |           |               |
  |13(300)| 2nd Indenting | 3.844 | 6.875 | Bulldozer | _a_, 18;      |
  |       |               |       |       |           | _b_, 15       |
  |       |               |       |       |           |               |
  |14(175)| Drill Hole in |       |       | Vertical  |               |
  |       | Primer Pocket |       |       | Drilling  |               |
  |       |               |       |       | Machine   |               |
  |       |               |       |       |           |               |
  |15(200)| Trimming      | 3.844 | 6.25  | Toledo    |               |
  |       | and Burring   |       |       | Trimmer   |               |
  |       |               |       |       |           |               |
  |16(180)| 5th Redrawing | 3.789 | 9.75  | Frog and  | _a_, 20;      |
  |       |               |       |       | Switch    | _b_, 40       |
  |       |               |       |       | Planer    |               |
  |       |               |       |       |           |               |
  |17(300)| Annealing     |       |       |           | _a_, 20;      |
  |       |               |       |       |           | _b_, 16       |
  |       |               |       |       |           |               |
  |18(180)| 6th Redrawing | 3.738 | 13.35 | Frog and  | _a_, 20;      |
  |       |               |       |       | Switch    | _b_, 45       |
  |       |               |       |       | Planer    |               |
  |       |               |       |       |           |               |
  |19(200)| Trimming      | 3.738 | 11.875| Toledo    |               |
  |       |               |       |       | Trimmer   |               |
  |       |               |       |       |           |               |
  |20(100)| Heading       | 3.738 | 11.750| 350 ton,  | _a_, 40 to 50;|
  |       |               |       |       | C. P. R.  | _b_, 50       |
  |       |               |       |       | Hydr.     |               |
  |       |               |       |       | Press     |               |
  |       |               |       |       |           |               |
  |21(180)| Annealing     |       |       |           | _a_, 40 to 50;|
  |       | Mouth         |       |       |           | _b_, 25 to 35 |
  |       |               |       |       |           |               |
  |22(300)| 1st Tapering  | 3.347 | 11.875| Bulldozer | _a_, 40 to 50;|
  |       |               |       |       |           | _b_, 35 to 40 |
  |       |               |       |       |           |               |
  |23(300)| 2nd Tapering  | 3.328 | 11.95 | Bulldozer | _a_, 40 to 50;|
  |       |               |       |       |           | _b_, 35 to 45 |
  |       |               |       |       |           |               |
  |24(40) | Machining     |       |       | Bullard   |               |
  |       | Mouth and     |       |       | Case      |               |
  |       | Head          |       |       | Machine   |               |
  |       |               |       |       |           |               |
  |25(80) | Hand Tapping  |       |       | Bench     |               |
  |       |               |       |       | Fixture   |               |
  |       |               |       |       |           |               |
  |26(80) | Reaming       |       |       | Bench     |               |
  |       |               |       |       | Fixture   |               |
  |       |               |       |       |           |               |
  |27(80) | Inspecting    |       |       | Various   |               |
  |       |               |       |       | Gages     |               |
  |       |               |       |       |           |               |
  |28(80) | Stamping      |       |       |           |               |
  +-------+---------------+-------+-------+-----------+---------------+

  * Number in brackets indicates Production Per Hour.

  Operations: Supplementary Information

  Lubricants   Cupping, Redrawing and Indenting     Viscocity
               Tapering                             Dry
               Machining Mouth and Head             Mystic

  Annealing Process (except Mouth)    Oil Furnace--1100 to 1140 °F
                                      Water Cooling and Acid Wash

  Annealing Process (Mouth)           Oil Burner--800 °F
                                      Cool in Air


=Summary of Operations on Cartridge Cases.=--The accompanying table
gives a summary of the cupping, drawing, annealing, indenting,
trimming, heading and machining operations on a British 18-pound
cartridge case of a composition of 70 parts electrolytic copper and 30
parts Bertha spelter. In the plant where this information was obtained,
the cupping, indenting, and first, second, third, and fourth re-drawing
operations are accomplished on bulldozers, while the fifth and sixth
re-drawing operations are accomplished on a frog and switch planer from
which the cross-head has been removed and a special fixture substituted
in its place. The punch is held rigidly in this fixture and the die on
another fixture clamped to the table of the planer. Practically the
same condition prevails on bulldozers. Here the punch is held rigidly,
whereas the die is held in the traveling slide. As a lubricant for
drawing a compound known as “viscosity,” manufactured by the Cataract
Refining Co., is used throughout, except on the fourth and fifth
re-drawing operations, where ordinary commercial vaseline has been
found to give the best results.

The annealing is done in a Quigley oil furnace, which is kept at a
constant temperature of between 1100 and 1140 degrees F. The cups are
handled in sheet-iron boxes with wire bottoms carrying 140 cups. This
furnace holds seven of these boxes; it requires 35 minutes for one lot
of cups to pass completely through the furnace. In other words, a box
is put in and taken out every five minutes, thus giving an annealing
time of thirty-five minutes on each batch. After dipping in water, the
cups are immersed in a weak solution of sulphuric acid to remove all
scale.

Scleroscope readings are taken before and after each drawing operation,
so as to ascertain whether the metal is being properly annealed or
not. The blank also is tested with a scleroscope before any work is
done on it, and should strike 15. The head of the shell must strike
between 40 and 50, being softer at the center than at the rim. The
readings are taken on four radii on the head, and at intervals of ¹⁄₈
to ³⁄₁₆ inch apart. In heading, considerable difficulty was at first
experienced in securing the correct scleroscope readings. Instead of
the head being harder at the rim than at the center, the reverse was
the case. It was found that the metal in flowing towards the center
packed up to such an extent that the case was made considerably harder
at this point. A method which overcame this difficulty consisted in
drilling a ¹⁄₄-inch hole down through the primer pocket previous to the
heading operation. This allowed the metal to flow towards the center of
the head with comparatively little resistance, and hence the correct
hardness was obtained at the rim, as well as in the center of the head.
The machining of the head and mouth is accomplished in Bullard special
cartridge case trimming machines of the double-ended type, that is,
one set of tools are located in one end for machining the mouth and
another set of tools held in the turret and on the cross-slide for
machining the head and primer pocket. Following this, hand-reaming
and hand-tapping operations are accomplished so as to get the desired
accuracy and fit in the primer pocket. Inspecting and stamping
operations finish the principal operations on the cartridge case.




CHAPTER VII

SPECIFICATIONS FOR THE MANUFACTURE AND INSPECTION OF THE RUSSIAN 3-INCH
SHRAPNEL SHELL


[Illustration: Fig. 1. Russian 3-inch Shrapnel Shell and Component
Parts]

The following specifications relating to the 3-inch Russian shrapnel
shell are abstracted from the official specifications, and contain
all the essential points required to be known by the manufacturer or
the inspector of shrapnel shells. The specifications deal in detail
with what is known as the “test consignment” of shells, the “proof
consignment” of shells, and the methods of inspecting.


=Clause 1. General Conditions.=--The shrapnel shell consists of the
following parts: steel body with copper driving band, steel diaphragm,
steel fuse tube, steel fuse base, brass socket nut, bullets, two steel
fixing screws, two steel threaded plugs, and a zinc plug. The selection
of the material to be used for the shell and the parts is left to the
discretion of the manufacturer, but on the condition that it meets the
requirements given in the following specifications. Before beginning
the manufacture of an order, the manufacturer must submit a _test
consignment_ of shells.


=Clause 2. Test Consignment of Shells.=--The selection of shells for
the test consignment is left to the discretion of the manufacturer. The
trials of the test consignment are carried out in the presence of the
inspector appointed by the government for which the shells are made,
and of the representative of the firm whose shells are tested. The
methods of manufacture of the test consignment of shells must be known
to the inspector and must be done in accordance with the requirements
in the following specifications. All shells forming the test
consignment must be similar in material and made by the same methods of
manufacture.

The submission of the test consignment is not required for those firms
who have already submitted one, and after the completion of an order
have received a new order for the same shells, provided the mechanical
conditions for manufacturing the same have not been altered. Firms
are allowed to begin the manufacture of the shells before delivering
the test consignment, but on the condition that in the case of
unsatisfactory results of the trials of the test consignment, all
shells previously manufactured by the firm must be rejected.

The test consignment consists of fifty shrapnels, out of which
twenty-five are tested, by firing, with a view to ascertaining their
accuracy and strength, twenty-two for strength only, and three
shrapnels are left for mechanical tests by breaking the test pieces
made from them in a testing machine. In the case of the last three
shells it is necessary to ascertain before cutting the test pieces
from them that the driving bands are pressed on correctly, by removing
them. In addition to this, the strength of the shrapnels is tested
by exploding them in a pit. For the pit test, those shells are used
which are found undamaged after being fired. For this trial, ten
shrapnels are used. Before firing the test consignment of shrapnels
and before the pit test, the mechanical test must be carried out, and
the two first mentioned tests may be carried out only if the metal
shows results answering the conditions mentioned in Clause 3 of these
specifications.

The test consignment will be considered as passed if the following
results are obtained:

1. If during the mechanical tests the metal answers to the conditions
laid down.

2. If during firing no shell is broken in the gun or immediately in
front of the muzzle.

3. If during firing no socket is separated from the shell in the gun or
immediately in front of the muzzle.

4. If on cylindrical parts of the bodies of shrapnels recovered after
firing no signs of the rifling are to be found. The slight impression
from rifling on the central portion of the shell cannot, however, be
taken as a reason for the rejection of the shell, provided that it is
noticed only on one-half of the circumference.

5. If shrapnels recovered after firing do not show any dent in their
bases or shearing of the socket, or if the increase in the diameter
of the cylindrical part of the body does not exceed 0.010 inch.

6. If shrapnels recovered after the firing do not show in more than 15
per cent of the cases the protrusion of the upper end of the central
tube from the countersink of the brass socket nut. All these shrapnels
must be dismantled for the inspection of the central tubes; the central
tubes must not show any considerable sign of buckling, cracks or
protrusion into the powder chamber.

7. (a) If during pit test, shrapnels do not show any breaking away of
the bases, if their bodies be found intact, and if the same results be
found on the shrapnels picked up after firing.

(b) If out of ten shrapnels tested in the pit not more than three show
broken bodies.

8. If shrapnels do not show the separation of driving bands from the
shell, nor displacement of same, if loosely fixed, and the accuracy
of the firing in a vertical plane be not below the requirements given
in Clause 19. The signs of the rifling on the driving bands of the
recovered shells should be correct and not enlarged.

If the results of the trial of the test consignment give unsatisfactory
results with reference to any of the above seven first conditions,
or to all of them, the firm will be allowed to submit a second test
consignment. In the case of unsatisfactory results of the test
consignment with reference to the eighth condition, the firm has the
right to submit additionally twenty-five shrapnels for accuracy firing
trials only, but these shrapnels must also answer to the other seven
conditions. If the trials of the test consignment show satisfactory
results, the firm may proceed with the manufacture of shrapnels, but
under the condition that the material and method of manufacture will be
similar to those used for the manufacture of the test consignment.

In the case of unsatisfactory results of the test of the second test
consignment, the contracting government has the right to cancel the
order with the firm for delivery of the shrapnels in question. All
the test consignments of shrapnels must be at the contracting firm’s
expense.


=Clause 3. Breaking Tests of the Material used for Bodies.=--These
tests must be carried out at the works where shrapnels are
manufactured. Three flat test pieces must be cut from the cylindrical
portion of the body parallel to its axis and immediately above
the driving band. The dimensions of test pieces are as follows:
Width, 0.750 inch; thickness, 0.150 inch; distance between marks, 2
inches. The outline and dimension of the ends must suit the holders
of the testing machine. The metal of the bodies will be considered
satisfactory if it shows a breaking strength of 82.7 kilograms per
square millimeter (52.5 tons per square inch) with a final elongation
of not less than 8 per cent. In addition to this, the inspector must
select two bodies from the test consignment before the beginning of
final machining for cutting from the round test pieces with a diameter
of 0.3 inch, length 2 inches between marks, three test pieces being cut
from each shell. The breaking test of these test pieces must be carried
out on the testing machine, and the elastic limit of the material must
be ascertained on them.


=Clause 4. The Proof Consignment of Shrapnels.=--As mentioned, the
shrapnels under order must be manufactured from similar material and
by similar methods to the shrapnels of the test consignment. The
acceptance of shrapnels for the service, however, can be effected only
after “proof tests” of the mechanical qualities of the metal used, of
the accuracy of firing, and of the strength and proper assembling, and
pit tests.

The whole order is sub-divided into consignments of 5000 shrapnels
each. The method of manufacture of the shrapnels must be entirely the
same for the whole consignment.

In the case of the order being placed for a number of shrapnel less
than 5000, the whole order will be treated as one proof consignment; in
the case of the order being placed for a larger number of shrapnels,
the remainder from a full proof consignment must be treated as a part
of the previous consignment, when it is less than half of the proof
consignment, and must form a separate proof consignment when it is more
than half of same.

The choice of shrapnels for proof must be made by the inspector
personally from the proof consignment submitted by the firm. The choice
must be made after final inspection of the whole consignment. The works
have the right to challenge the shrapnels chosen by the inspector
for the proof, having the right to do it only twice. The shrapnels
challenged in that manner must be destroyed, so as to prevent any
further submission of same for proof. The shrapnels challenged must be
replaced by the firm.

For the mechanical tests of the metal, it is recommended to select
bodies which were rejected on account of their dimensions, but in the
case of the absence of any bodies rejected for the dimensions, the
works must provide good bodies selected by the inspector. Not less than
ten bodies must be chosen from the proof consignment. The rules and
requirements for the metal used for the shrapnel bodies were given in
Clause 3.

In the case of satisfactory results of these mechanical tests, the firm
must submit from each proof consignment fifty shrapnels for the firing
trials for their strength. After firing trials, the pit tests must be
carried out, for which proof recovered shrapnels which do not show any
damage after firing will be used. Ten shrapnels must be used for pit
tests.

All proof tests must be carried out in the presence of the inspector
sent for this purpose to the works, and the mechanical tests of the
metal must be carried out by the inspector himself. The projectiles
used for the proof firing must not be painted but only covered with
machine oil.

The consignment will be accepted if the mechanical or firing proof
tests fulfill the same requirements as have been laid down in Clause 2,
Conditions 1 to 8, with the exception that in Condition 6, in the case
of the proof test, 20 per cent, instead of 15 per cent, as in the case
of the consignment test, may show protrusion of the upper end of the
central tube from the countersink of the brass socket nut.

If, during firing, breakages of the shrapnels in the gun or immediately
in front of the muzzle should occur, the whole consignment must be
rejected.

In the case of unsatisfactory results with reference to trials
mentioned in Clause 2, Conditions 3, 4, 5, and 6 (which must not be
more than one shell with reference to Conditions 3, 4, and 5), the
firm has the right to submit 100 additional shrapnels chosen by the
inspector for the firing for recovery proof. If during pit tests more
than three shrapnel bodies are broken, an additional five shrapnels
must be subjected to the same test, but for the acceptance of the
consignment it is required that, in total, no more than five broken
shrapnel bodies occur.

With reference to damaged or displaced driving bands, or the impression
of the rifling on them not being clear, or being enlarged, it is left
to the discretion of the contracting government to demand the changing
of the driving bands on the whole consignment, after which rebanding
they must be submitted for second proof, twenty-five shrapnels being
tested for accuracy: these shrapnels must be chosen by the inspector
after reviewing the whole consignment. If during the secondary firing
trials which take place on account of failures with reference to any
one of the above-mentioned reasons, further failures to the same effect
take place, the question of the acceptance of the whole consignment
must be referred to the respective military administration.

In the case of the failures of both trials, first and secondary, the
permission for the further manufacture of projectiles by the firm in
question will be left to the discretion of the respective military
authorities.

In the case of the acceptance of the consignment after the proof,
the shrapnels used for the proof in question, fifty in number, must
be taken from the order. Any other shrapnels, used for proof in
addition to the above-mentioned number, must be at the expense of the
manufacturer.


=Clause 5. The Rights and Duties of the Government Inspector.=--The
inspector’s duty consists not only in the acceptance of the
manufactured shrapnels, but also in looking after the methods, etc.,
used in the manufacture. In order to do this, the inspector must
be given the right of access to any work and test referring to the
shrapnel manufacture.

The inspector has the right to inform the manager of the works of all
defects noticed by him in manufacture of the shrapnels, as well as of
those which occur in the shrapnels submitted for acceptance, and he
has the right to suggest improvements to the manufacturer; it is left
to the discretion of the manager of the works to make use of these
suggestions, if it is found advisable, but the inspector has not the
right to interfere with the orders issued in the works.

Before submitting to the inspector the shrapnels manufactured the
works must pass them by their own examiners; these examiners must work
to the instructions given to them by the works, and prepared to the
inspector’s satisfaction. The inspector has to gage shrapnels by the
gages stated in the following specifications. He also must check them
with reference to their dimensions, as given on the drawings, before
beginning inspection.


=Clause 6. The Condition in which Shrapnel Bodies are
Submitted.=--Steel shrapnel bodies are submitted to the first
inspection without socket, driving band, and inner parts. The outside
cylindrical portion of the bodies as well as the enlarged centering
portion must be machined and finished; shrapnel bodies must be
submitted with grooves for driving bands and with other grooves in the
base of the shell.

The rounded portion of the bodies above the enlarged centering portion
must be machined only preliminarily. The inside of the bodies must be
finish-machined, and the shoulder for the diaphragm as well as the
cylindrical portion of the body against the diaphragm must be properly
finished; the upper part of the inside surface must be provided with
threads for socket. The remaining portion of the inside surface might
be roughly machined. The base of the shrapnels may be left with a boss
outside with center marked on it, but the remaining portion of the base
must be finish-machined. This applies to the first inspection.


=Clause 7. The First Inspection of Shrapnel Bodies.=--The surface
of the enlarged centering portion must be perfectly smooth and the
cylindrical portion of the bodies must not show any tool marks,
except slight ones. The outer surfaces of the central portion and
the enlarged centering portion must be polished. Special care must be
taken in polishing the enlarged centering portion. The inside surface
of the bodies must be clean and smooth. The outer and inner surfaces
of shrapnels must not show any cracks, fissures, or black lines (not
even the very slightest of these), nor burrs. The inner surface of the
bodies may show separate dents due to slag, but these dents must be of
a very slight nature. The thread in the upper end of the bodies for the
socket must have at least five full turns.


=Clause 8. The Checking of the Weight of Shrapnel Bodies.=--Out of
each one hundred bodies submitted to the inspector, at least ten
bodies must be weighed. These weights will assist the inspector with
reference to the dimensions of the bodies, and might draw his attention
to the dimensions of those parts for measuring of which there are no
gages provided. In addition to this, during the manufacture of the
test consignment, the inspector must ascertain the mean weight of the
shrapnel bodies in this consignment, as well as any possible variation
in any direction.


=Clause 9. Inspection and Test of Copper for Driving Bands.=--Pure
copper is used for the driving bands. It must be of the best quality,
and hard drawn; ordinary copper, not drawn, must not be used for
driving bands. The copper strips must be cut into pieces of the lengths
required for their placing on the shrapnels. The copper strips must be
submitted to the inspector for acceptance and for the following tests:

1. The strips must be bent double in cold condition until the ends
meet; when the ends meet, the strip is hammered until both halves
are flat; if during this test the strip does not show any cracks or
breakages, the metal will be considered as accepted.

2. The strip is hammered in cold condition until its thickness is
reduced one-half; after this trial it must not show any fissures or
cracks.

Not more than 1 per cent of the strips submitted must be subjected to
the above tests.

If it is found that any of the strips tested will not stand the tests,
the whole consignment of strips is rejected, or is returned to the firm
for reviewing, so as to give the firm the possibility to submit again
that part of the consignment which might be considered good. During
secondary test another 1 per cent of strips will be chosen, and in the
case of any failures the whole consignment will be finally rejected.

In case of satisfactory results in the tests mentioned, the inspector
examines the copper strips so as to ascertain that they are of proper
cross-section; special notice must be taken with reference to fissures.
Fissures exceeding one-tenth of the strip in length are not allowed.
The inspector must examine 20 per cent of all strips, and, during this
examination, if even one strip be found with fissures longer than
mentioned, the whole consignment of strips will be returned to the firm
for reviewing. If during secondary examination the inspector finds even
one fissure exceeding the mentioned length, the whole consignment of
copper will be rejected.


=Clause 10. Fixing of Driving Bands.=--To prevent cracks in shrapnel
bodies during the fixing of the driving bands, a mandrel must be
placed inside the bodies, and this mandrel must fit the inside surface
of the bodies tightly. The inspection of the grooves must be carried
out by means of the gages made by the firm to suit the inspector’s
requirements. To facilitate the fixing of the driving bands on the
shrapnel bodies, the bottom of the grooves may be provided with waved
ribs. The depth of these grooves must not exceed 0.005 inch. The width
of the surface with the waved ribs is left to the decision of the firm
and inspector.

The method of fixing the driving bands is left to the discretion of the
firm, the only requirement being that the order must be manufactured
by the same methods as used for the manufacture of test consignment,
provided that the firing trial of that consignment was satisfactory.
The number of shrapnels supplied by the firm for this firing and for
the inspection of the driving bands is mentioned in Clause 2. If the
firm is proposing to alter the method of the fixing of the driving
bands, it must submit, at its own expense, a test consignment of 25
shrapnels for firing trials.

During the manufacture of the order for shrapnels the inspector has
the right to choose, if he thinks it necessary, from each consignment
submitted to him, not more than 1 per cent of the projectiles for the
removal of their driving bands, in order to ascertain how close they
are to the shrapnel bodies. The inspector also has the right to demand
an accuracy trial with some of the above-mentioned shrapnel, but in
this case he must give detailed reasons for doing so. If the results of
this firing are unsatisfactory, the military authorities have the right
to demand the replacement of driving bands on the whole order.


=Clause 11. Secondary Inspection of Shrapnel Bodies after the Firing
of Driving Bands.=--The shrapnels are submitted for the secondary
inspection with fixed driving bands, finished sockets, steel diaphragms
in place, central tubes and socket nut, but without socket fixing
screws, as well as fuse fixing screws. The central bosses on the base
must be cut away in cases where the shrapnels were submitted with them
for the first inspection. The powder chamber, lower portion of steel
diaphragms, and inner surface of central tube must be covered with
durable varnish.

During this inspection special care must be taken to ascertain the
proper fixing of the driving band. The proper fixing of the driving
bands is ascertained by (1) sounding them with small hammers, and
(2) removal of driving bands from some shrapnels, preferably those
rejected. The driving bands when being sounded with hammer must not
make any jarring sound. The jarring sound is only allowed at the joint
of the driving band, for not more than one-tenth of its length; the
bands not answering to these conditions must be replaced by new ones.
The driving bands, after being removed from the shrapnel, must have
impressions of the waved grooves on the bottom of the groove; the
inside surface must not show the pink color of the unused copper, but
must be smooth and give a slight reflection.

When removing the driving band, special attention must be paid to the
fact that the bands fit properly into the sides of the groove, and
that they are close to the shrapnel bodies. In the case of copper
strips being too wide, the shrapnel bodies show cracks, sometimes on
account of the method of fixing and sometimes on account of too high
a pressure. These cracks can be ascertained by sounding the shrapnels
with a hammer; the cracked shrapnels will make a dull sound. Such
shrapnels must be rejected.

During secondary inspection, the inspector must ascertain the following
facts:

1. If the powder chamber, lower surface of steel diaphragms, and inner
surface of the central tube are varnished; if steel diaphragms fit
properly in the corresponding place of the shrapnel bodies; steel
diaphragms must bear on the lower surface of the shoulder and must
be in close contact with the inside surface of the shrapnel bodies.
Special care must be taken with reference to the tight fitting of the
steel diaphragms.

2. The base of shrapnel bodies must be absolutely smooth; attention
must be paid to the presence of rough surfaces; black spots, cracks,
or any damages, which are not allowed on the site of the central boss;
shrapnel bodies with such defects are not allowed.

The final finishing of the driving band may be done after the shrapnels
are nickel-plated, at the discretion of the inspector.


=Clause 12. Inspection of Steel Diaphragms.=--Diaphragms are made from
steel stampings under the hammer or press. The metal, with reference to
the mechanical qualities, must meet the requirements set forth for the
shrapnel bodies (see Clause 3). The holes for the central tubes must be
drilled; these holes must be made with a shoulder for the central tube;
the outer surface of the diaphragm, as well as the shoulder of the hole
for the central tube, must be accurately machined. The diaphragms must
not show any cracks or other defects.

The test of the metal for the diaphragms consists of hammering them by
the dropping of a weight from a certain height. The number of blows
which the diaphragms can stand without any cracks must be ascertained
by the inspector during the manufacture of the test consignment of
shrapnels. In addition to this, the quality of the metal must be
ascertained by the Brinell test. During firing, the diaphragms must
not show any dents; this fact must be ascertained on some shrapnels
recovered after the firing.

The manufacturer must supply the inspector with ten diaphragms for
the mechanical tests of material. These diaphragms will be chosen
by the inspector from the total number of diaphragms for the whole
consignment. For the hammering tests, not more than one per cent of the
total diaphragms must be chosen, and the Brinell test must be carried
out on not less than one per cent of the whole number of diaphragms. In
the case of satisfactory results, the whole consignment is accepted;
otherwise, additional tests on two per cent of the diaphragms must be
carried out, and in the case of unsatisfactory results, even on one
diaphragm, the whole consignment will be rejected. Diaphragms must be
submitted for inspection in quantities not less than 200. The lower
surface of the diaphragm must be varnished after inspection.

In the case of the manufacturer being allowed to make shrapnels without
submission to test consignment, as per Clause 3, the inspector must
test the diaphragms as usual.


=Clause 13. Inspection of Central Tube.=--The central tubes must be
made of steel, must not show any cracks, must be properly welded, and
must be of similar thickness on the whole length. For the purpose
of ascertaining the mechanical qualities of the metal used for the
central tubes, small cylinders ⁵⁄₈ inch in length (1¹⁄₂ times the
diameter of the tube) must be cut from some of the tubes which have
been previously properly measured; these cylinders must be subjected
to a compression test under the press. The minimum resistance shown by
these cylinders under compression, before the beginning of buckling,
must be not less than 14.45 tons per square inch. The outer as well as
the inner surfaces of tubes must be smooth and their ends must be cut
perpendicular to their axes. The length of the tube is ascertained
during the assembling of the shrapnel. In the assembled shrapnel, the
upper end of the central tube must be inside of the countersunk hole
provided for in the socket nut.


=Clause 14. Inspection of Sockets.=--Sockets must be manufactured from
steel. The breaking strength of steel used for sockets must be of about
60 kilograms per square millimeter (38.1 tons per square inch), with an
elongation not less than 16 per cent (the distance between marks being
2 inches). Sockets are submitted for inspection in quantities of not
less than 100; they must be tapped with thread on the inside as well
as on the outside surfaces; the conical portion of the surface must be
machined; the upper surface must be machined, but this machining may be
left rough at this stage; those parts of the sockets by which they are
fixed to the shrapnel bodies must be accurately machined; the sockets
must be accurately cut. The sockets must be provided with two holes,
one for filling with resin, and another one for the escape of gases. If
sockets are stamped, the outer surface of the stem can be left without
machining, but it must be very smooth. The upper surface of the sockets
may be submitted to the inspector without being finish-machined. The
sockets must not show any signs of cracks, fissures or any rough
surface. Chipping in the thread of the hole or on the conical fuse seat
may be allowed, but of a very slight nature.

To ascertain the mechanical qualities of the metal used for sockets,
the inspector has the right to carry out the tests on one per cent of
the sockets from each consignment. For this purpose, rings must be cut
from the upper portion of the sockets, and these rings are subjected
to the hammering test by a weight dropped from a certain height. In
addition, the sockets must be tested with the Brinell test, and for
this purpose not less than 1 per cent of the sockets must be used.


=Clause 15. Inspection of Brass Socket Nuts.=--The socket nuts must
be cast of an alloy consisting of 2 parts of copper and 1 part of
zinc, taken by weight. The socket nuts are submitted to the inspector
after being finally machined, threaded, with finished upper and lower
surfaces, with central hole made to the drawing, and with slot for the
key. Socket nuts must not show any defects.


=Clause 16. Bullets and Smoke Compositions.=--Bullets must be of a
true spherical shape; they must be cast of an alloy consisting of 4
parts of lead and 1 part of antimony, taken by weight; sprues must be
cut off, and the surface of the bullets must be smooth. The diameter
of the bullets is 0.5 inch; mean weight, 0.376 ounce. Separate bullets
may differ from the mean weight, but they must not be less than 0.373
ounce, and not more than 0.381 ounce. Under slight hammering the
bullets must not show any cracks. The force of the blow must be decided
by the inspector, the reason for this test being to ascertain if the
bullets can be used in shrapnels where they are slightly compressed,
as after this pressure they must not show any cracks. Shrapnel must
contain from about 256 to 265 bullets.

The bullets must be placed in proper layers, and each layer must be
slightly pressed in, but after this pressure bullets must not be
deformed to any noticeable extent, except those in the bottom layer.
Layers consist of 17 or 18 bullets, except the top layers, which have
about 20 bullets each. The five bottom layers of bullets must be
covered with smoke composition made of metallic antimony and magnesium
in the following proportions, by weight: 55 parts of antimony and 45
parts of magnesium; 0.75 ounce of smoke composition must be put in each
shrapnel. This composition must be put in after the first five layers
of bullets are in place, and the shrapnel must be shaken in order to
settle the powder. The smoke composition must ignite very quickly. The
inspector must see that the composition is made from the magnesium and
antimony as stated above. With bullets in place, and with socket in
proper position, the shell must be filled with melted resin.


=Clause 17. The Third Inspection of Shrapnels and Checking of Their
Weight.=--The shrapnels for the third inspection are submitted
after being fully assembled and charged with the bullets and smoke
composition, and after being filled with resin; the holes in the
sockets used for filling with resin and for the escape of gases must
be stopped with threaded steel plugs. These plugs must be riveted over
and polished flush with the surface of the socket.

During the third inspection, the shrapnel is gaged with special gages
to check shape; the hole for the fuse is tested by a special screw
gage; copper driving bands must be inspected and gaged. After this
inspection the shrapnels are weighed. The shells which show the ends of
the driving bands not completely touching each other, may be accepted
if the distance between them is very small.

The outer surface of the socket must be finish-machined and must be
smooth and perpendicular to the center line of the fuse socket. The
socket must be fixed by means of steel screws, the outer ends of which
must be cut flush with the surface of the shrapnel, and polished over.

During this inspection, the inspector must ascertain that the head
portion of the shrapnels does not show any cracks due to the drilling
and tapping of the holes for the screws. The head of the shrapnel must
be provided with a tapped hole for the fuse securing screw. The head
of this screw must be flush with the shrapnel bodies. The upper end of
the central tube must fill completely the countersunk part provided for
it in the socket nut, if it is in proper position. The steel gage rod
dropped into the opening of the central tube must reach the base of the
shrapnel.

To ascertain the proper assembling of the inner part of the shrapnels,
the inspector has the right to demand dismantling of not more than 0.5
per cent of the shrapnels submitted. While inspecting the dismantled
shrapnels, the inspector must ascertain the following points:

1. If the thread of fixing screws for socket and fuse, as well as the
threads in holes for them, are cleanly cut, and if the length of these
screws is sufficient.

2. If the socket remains steady when screwed into the shrapnel bodies,
before being fixed with screws.

3. If the end of the central tube remains clean and the central tube
itself is not damaged by the bullets.

4. If the bullets are covered with resin and if the shrapnels are
filled with smoke composition.

5. If the number of bullets is correct, and also that they are not
appreciably damaged after pressing.

6. If the steel diaphragm is in the right position in the shrapnel.

After the third inspection the shrapnels must be weighed; the normal
weight of the assembled shrapnels, without zinc plugs, must be 13
pounds 7.33 ounces ± 1.053 ounce. All shrapnels passed by the inspector
must be stamped on the base.


=Clause 18. Nickel-plating, Varnishing and Oiling.=--All the outside
surfaces of the shrapnel with the exception of the copper driving
bands must be nickel-plated and varnished. This nickel-plating and
varnishing must be durable. The manufacturer must take steps to
prevent the passage of the liquid inside of the shrapnels during
nickel-plating. The shrapnels must be inspected by the manufacturer
after being nickel-plated so as to ascertain that no liquid passed
inside the powder chamber, and, if necessary, the chamber must be
cleaned. The shrapnels must be submitted for final inspection after
being nickel-plated and varnished.

The socket in the front portion of the shrapnel must be oiled and
covered with the zinc plug shown in Fig. 1; the socket must be fitted
with fixing screws for the fuse; the screws must be oiled with naphtha
grease. The copper driving bands must be gaged during this inspection.
While inspecting the shrapnels, the inspector must see to the following
points:

1. That the driving bands are not damaged; shrapnels with damaged bands
must be returned to the works for new bands.

2. That the nickel-plating of the shrapnels is sound and that the
nickel-plated surfaces do not show any signs of rust.

3. That the fixing screw for the fuse is properly cut; the top of this
screw, when screwed completely down, must slightly protrude over the
surface of the shrapnel. The threads must be Whitworth, 24 threads per
inch. A plug and ring gage must be provided for gaging this thread.

4. That the socket is free from rust.

5. That the powder chamber, as well as the inside of the central tube,
is clean.

The zinc plug must fit properly to the upper surface of the fuse
socket. The copper driving bands must be oiled with naphtha grease
to prevent them from corroding. The shrapnel, before shipping from
the works, must be packed in strong wooden boxes. The details of the
packing is left to the discretion of the manufacturer, provided that
it is approved by the inspector. While packing, care must be taken to
place driving bands in guards to prevent their being damaged by knocks
from the outside, or from rattling one against the other, or against
the packing during transport.

The number of shrapnels packed in one box must not exceed, in weight
(box included), 253 pounds.

When shipping the manufactured shrapnels from the works, two spare fuse
fixing screws must be put in every box. Spare zinc plugs, 5 per cent of
the total number supplied, must be delivered together with order and
packed in separate wooden boxes, 50 in each box.


=Clause 19. Firing Tests.=--The works must deliver the required number
of shrapnels to the place where they will be tested. The proof by
firing will be carried out with a 3-inch quick-firing gun with a charge
of smokeless powder, and with chamber pressure of 2400 atmospheres
(15.75 tons per square inch).

The recovery proof must be carried out without bursting charge, but
the shrapnels must be fitted with time fuses. When time fuses are not
available, the proof must be carried out with steel or brass dummy
fuses similar to those used for accuracy trials. These dummy fuses must
be supplied at the expense of the firm. Every shrapnel must be weighed
and the weights taken down.

The time fuse must be set a distance of from 1400 to 1635 yards. It
must be noticed whether or not the fuse explodes. To obtain the best
conditions for observation, the firing must take place with sight set
up 10 divisions higher than is required by the range. Up to one-third
of the shrapnels proved for recovery must be fired with bursting
charge, so as to ascertain that they are properly assembled. The fuse
socket in the last mentioned cases must be plugged with dummy fuses.

The firing must be carried out at such a range as to enable the
recovery of the shrapnels for inspection and measuring of same; all
shrapnels, before firing, must be measured on their cylindrical
portion and the accuracy of the base must be ascertained, in order to
facilitate notice being taken with reference to the bulging of the
bodies and bases of the shrapnels. The diameters of the cylindrical
portion must be taken in sections two inches apart. Marks must be made
on the copper driving bands and on the cylindrical part of the shrapnel
bodies adjacent, to facilitate notice being taken of the displacement
of the driving band, if such takes place.

For accuracy trials, shrapnels without time fuse must be used, and
special steel or brass dummy fuses must be screwed in; the outline
and weight of this dummy must be similar to that of the fuse, and the
weight of the shrapnel with such dummy must be 14 pounds 5.33 ounces.
These dummy fuses must be made by the manufacturer at his expense. The
accuracy trials must be carried out by aiming the gun at a vertical
target at a range of 2335 yards.

After the firing trial for recovery and for accuracy, the maximum
possible number of shrapnels must be recovered and inspected, as to any
marks from the rifling on the shrapnel bodies, any dents or damages on
bases or heads, any displacement of the driving bands or any shrapnels
with broken off bases. To ascertain the accuracy of fitting of the
steel diaphragms, and the condition of the bullets, two shrapnels must
be dismantled. In addition, all those shrapnels which have displaced
central tubes must be dismantled. The shrapnels must be measured on
their diameter in order to ascertain the deformations. A pit test must
also be carried out. The shrapnels must be fully loaded for the pit
test and must be fitted with ordinary zinc plugs screwed into the fuse
sockets.




CHAPTER VIII

SPECIFICATIONS FOR THE MANUFACTURE AND INSPECTION OF THE COMBINATION
FUSE FOR RUSSIAN 3-INCH SHRAPNEL SHELLS


The following specifications contain all the essential information
relating to the Russian aluminum 22-second combination or double-acting
fuse for shrapnel shells used in 3-inch quick-firing field and mountain
guns, as given in the official specifications. This chapter, therefore,
contains a complete description of every part used in the fuse,
together with complete details relating to the manufacture, inspection,
and tests.


=Component Parts of Fuse.=--The fuse consists of over thirty separate
parts, the names of each of which are specified in the table below,
together with their weights.

                 FUSE PART                              Weight in Ounces,
                                                             Avoirdupois
  Stem (with cloth)                                            3.7166

  Chamber bushing with needle for percussion detonator
    cap (without powder)                                       0.1971

  Bushing with needle for time detonator cap                   0.0331

  Plug (brass) in the flange of the stem                       0.0150

  Upper time ring (complete with powder; for filling in
    both upper and lower time ring 0.24075 ounce avoirdupois
    of powder (fuse) are required; for 1000
    fuses, the following quantities of fuse powder are
    required: for pressing into the time rings, approximately
    16.25 pounds avoirdupois; for powder pellets
    in the vents of the lower time ring, approximately
    3.912 ounces avoirdupois) with powder and parchment        1.1586

  Lower time ring (see note in parenthesis on upper time
    ring) with powder, asbestos, pins, and tin disk            1.1496

  Nut                                                          3.6278

  Two set-screws for nut                                       0.0361

  Tightening ring (split)                                      0.5492

  Time detonator (assembled)                                   0.2632

  _Time detonator parts_:
    Pellet                                                     0.1429
    Rod                                                        0.1023
    Spiral brass spring                                        0.0030
    Cap                                                        0.0150

  Safety bushing for the time detonator (the bushing for
    the time detonator for mountain guns weighs 0.0677
    ounce avoirdupois)                                         0.1128

  Percussion detonator (assembled)                             0.4514

  _Percussion detonator parts_:
    Pellet                                                     0.3671
    Brass bushing                                              0.0451
    Lead disk (washer on flange)                               0.0226
    Cap                                                        0.0166

  _Safety arrangement for percussion detonator_:
  Brass safety stirrup with brass control spring               0.0481

  Steel spiral spring                                          0.1655

  Lock bushing for the safety stirrup for percussion
    detonator                                                  0.5597

  Base plug with counter safety lug and brass disk             0.5718

  Lead disk                                                    0.1520

  Powder for the chamber bushing and transmitting duct
    of stem                                                    0.0572

  Mean weight of complete and ready-for-firing fuse for
    3-inch field gun                                           2.8628

  Mean weight of complete and ready-for-firing fuse for
    3-inch mountain gun                                        2.8177

  The weights of the additional parts not included in
    above list are:

  Tin protecting cover with tape                               1.0533

  Copper wire for removing the cover                           0.1053

  Shell grease for lubricating grooves of stem                 0.0196


=Design and Construction of Stem.=--The stem is to be cast of aluminum
(or an alloy of aluminum and copper) and pressed. The top of the stem
is to be turned on the outside into three cylindrical shoulders, the
upper one being threaded for receiving the nut; on the surface of the
two upper shoulders, parallel to the axis of the stem, three guiding
grooves are milled. The base of the stem top serves as a turning axis
for the lower time ring. The interior of the top of the stem is to be
bored out to form three cylindrical chambers, the lower of which is
threaded to receive the brass bushing with the conical steel needle;
the latter is lacquered and inserted into the bushing from the bottom,
its head being riveted. To prevent the unscrewing of the bushing, the
latter is nipped in two places. A vent is drilled through the wall at
the top of the stem.

The upper face of the flange of the stem has a rim on its
circumference, and on a radius located in a vertical plane with the
vent of the stem top, a transmitting duct is drilled, reaching from
the lateral surface of the flange to the powder chamber of the fuse;
the upper face of the flange communicates with this duct through an
ignition hole pasted onto the top with a muslin disk. The transmitting
duct (covered with a neutral varnish) is filled, in the assembled fuse,
with grain powder (for 100 fuses, about 3.84 pounds avoirdupois of
unpolished rifle powder is required) and closed with a brass plug. On
the lateral surface of the flange two annular grooves are milled out,
the lower of which has four recesses for staking in the tin cover.

On the lower face of the flange (two marks shall be placed on this
face, one giving the last two digits of the year of manufacture of the
fuses, and the other the number of the control consignment of the same
year), at the ends of a diameter, two slanting cuts are milled for the
wrench which screws the fuse into the shrapnel. On the same lateral
surface a conical mark is cut, colored red, for the setting of the
graduations of the fuse; on the top face of the flange a cloth washer
is pasted, with a hole punched in it over the ignition hole. The cloth
is pasted with a special thick varnish which is also used for pasting
the twilled tape to the cover. The varnish consists of white resin,
shellac and turpentine soluble in alcohol. Through the lateral surface
of the flange a hole is drilled, leading to the lower face of the
flange and intended for fastening the copper wire for tearing off the
cover.

The _tail of the stem_ is shaped with a smooth cone on the top and a
threaded cylinder at the bottom; the interior of the tail is to be
bored out to form three cylindrical chambers, the upper and lower of
which are threaded to receive the chamber and the base plugs, and the
smooth, middle one, is intended for the percussion arrangement.


=The Chamber Bushing.=--The chamber bushing (brass) has four holes in
its bottom for transmitting the flame into the interior of the shrapnel
shell, and one central hole into which the varnished steel needle is
screwed from the top. The lower face of the bottom of the bushing
is recessed for locating the compressed brass counter spring of the
percussion safety stirrup. The inside surface of the bushing is covered
with neutral varnish, and, before filling it with powder, a muslin and
wax paper disk are deposited at the bottom. The powder in the bushing
is compressed slightly, to prevent its scattering in handling, before
screwing the bushings in their places. The screwed-in bushing is nipped
in two places and its wall is drilled through the transmitting duct,
before charging the latter, for exposing the powder in the bushing.


=The Time Rings.=--Both time rings are cast from an aluminum-copper
alloy (copper from 2¹⁄₂ to 3 per cent) and stamped in a die; on the
under side of each ring a groove with an intervening bridge and
semicircular arch is formed by first stamping it in a die and then
milling it. The grooves are coated on the inside with Ossovetski’s
neutral varnish, and fuse powder pressed into them. The portions
filled with powder are then turned off and a thin, parchment washer
pasted on their under surface with a neutral varnish. The parchment of
each time ring is punctured over the transmitting hole, to hasten the
transmission of the flame in grape-shot firing.

The _upper time ring_ is turned on the inside to form two cones
connected by a circular section; the lower cone also terminates into a
circular section having three protruding lugs fitting into the three
slots of the stem top, thus allowing the time ring to slide vertically
only along the axis of the fuse. On the upper side of the time ring an
annular groove is to be turned for the reception of a soaked leather
washer. From the lower cone of the time ring an oblique hole is to
be bored, near one end of the bridge (left end in looking at the
lower end of the time ring) communicating with the transmitting hole
drilled through the composition groove. Through this oblique hole
the composition is ignited from the time detonator cap of the fuse,
assisted by the powder preparation pasted by means of alcohol varnish
on the side wall of the hole next to the bridge. From the circular
section connecting both cones of the time ring to the under side of the
same, four gas escape holes are provided, facilitating the escape of
the gases from the burning lower time composition.

The _lower time ring_ is turned on the inside, providing a slight
cylindrical shoulder fitting on the base of the stem top and turning
freely around same. At one end of the intervening bridge (opposite
the one in the upper ring) a transmitting hole is drilled through the
bottom of the composition groove of the time ring, transmitting the
flame from the upper to the lower composition. To insure the ignition
of the composition, a powder pellet with a central hole is inserted
into the transmitting hole. From this transmitting hole, a gas escape
hole, located on a radius of the time ring is provided, which at its
base has a bursting charge of powder (varnished) pressed into it,
plugged up with asbestos, and covered with a foil ring pasted with
varnish. This hole facilitates the escape of gases from the burning
composition of the lower time ring. The asbestos plug prevents the
possibility of a premature ignition of the lower composition from the
upper one, and the powder charge is intended for an immediate clearing
of the plugging at the gas escape hole soon after the ignition of the
lower composition through the transmitting hole. The lateral surface of
the lower time ring is provided with:

1. Four pairs of pins inserted into corresponding holes for the setting
of the fuse by hand.

2. Two holes for a wrench, if same should be required for setting the
fuses.

3. Graduation from 10 to 130.

4. Separate graduation marked with the digit “5.”

5. One notch marked in red and one notch marked in black with letters
as directed by the contracting government.

The upper side of the lower time ring is covered with a cloth washer
having an opening opposite the transmitting hole.


=The Brass Nut.=--From the outside, the nut presents a rounded surface
terminating into an umbrella. Inside the nut a thread is cut for
screwing onto the top of the stem; the threaded hole opens into an
oval cylindrical cavity communicating with the outside atmosphere by
means of four openings in the neck of the umbrella. The edges of these
four openings are milled out on a side opposite to the direction of
the rotation of the shell to facilitate the escape of gases. At the
bottom of the nut an arch-like annular recess is milled out for the
accumulation of gases from the burning compositions of the time rings,
whence they escape into the above-mentioned oval cylindrical cavity
through four inclined channels, and then out of the fuse through the
openings in the neck of the umbrella. The nut is provided with two
brass screws for securing it in place, after being screwed home on the
top of the stem.


=Upper Percussion Arrangement.=--The upper percussion arrangement
consists of a brass time pellet and safety ferrule; the time detonating
cap is inserted into the pellet and is held in place by means of a
brass rod and brass spiral spring wound on the head of the latter.
The safety ferrule is a hollow cylinder with a side slot, resting on
the shoulder between the upper and lower chambers of the stem top. In
its outside appearance the time pellet represents a cylinder of two
different diameters connected with a conical slope; with the latter,
the pellet resting on the conical enlargement of the ferrule. The lower
cylindrical part of the pellet slides into the inside of the ferrule,
and the upper, together with the projecting part of the rod, is located
above the top of the stem in the cavity of the nut leaning with its
steel spring against the arch of the cavity. The rod is kept firmly in
place, being staked in on the circumference of the joint in two places.

On the top of the stem, embracing the middle smooth cylindrical
portion, the brass conical tightening ring is put on, fitting into the
conical seat of the upper time ring. The ring is provided with a pin,
which is guided in its movements by one of the three grooves in the
top of the stem, opposite the vent. In order not to cover up the vent
in the stem top, a longitudinal slot is cut in the ring opposite the
former; the eight other grooves on the outside of the ring facilitate
the tightening of the ring.


=Lower Percussion Arrangement.=--The lower percussion arrangement
is located in the tail of the stem between the chamber and the base
bushing and consists of a percussion pellet, lock bushing, brass safety
stirrup with counter spring, steel spiral spring, and lead washer. The
brass percussion pellet, turned all over, is provided with: 1. Bottom
shoulder resting on lead washer in base plug; the top of this shoulder
is turned off and the strips of the counter safety catch hold onto
it. 2. Cylindrical shoulder with lower turn of steel spiral spring
embracing same and guiding the compression of the spring when the lock
bushing is settling down. 3. Lead washer with rectangular opening,
coated with varnish, and placed on the upper face of the shoulder. 4.
Parallel faces along which are placed the leaves of the safety stirrup.
On the upper part of the two opposite faces of the percussion pellet
transverse cuts are milled out into which special tongues of the leaves
of the safety stirrup fit. The safety stirrup with the counter spring
soldered to it has four leaves, two of which (opposite ones) are bent
in the middle outwardly and two of which are straight, with only a
slight outward bend at their ends; the latter leaves have tongues for
fitting into the cuts of the pellets, as shown in Fig. 4, Chapter I.

The lock bushing is a hollow brass cylinder, the outer upper portion of
which is rounded off and made wider than the lower one; the interior is
bored out cylindrically and then widened into a cone, which catches the
straight leaves of the safety stirrup when the lock bushing is settling
down, thus preventing the latter from moving upwards. The steel spiral
spring in conjunction with the bent leaves of the stirrup hold the lock
bushing over the percussion pellet. The percussion cap is kept in place
by means of a brass bushing which is staked in from below in two places.


=Base Plug.=--The base plug, which is made of brass, has an annular
groove formed at the bottom near the wall, which serves for fastening
the counter safety lugs made of two strips of copper. At one end, the
lugs are inserted in the groove (at the opposite ends of a diameter),
and at this place the metal is jammed; with their other ends the lugs
catch onto the shoulder of the bottom flange of the percussion pellet,
inserted in the base plug together with the lead washer. The base plug
has a flat bottom with a central opening covered with a brass disk; in
order not to leave any space between this disk and its seat, the former
is covered with varnish from below; two other holes at the bottom of
the bushing, not drilled through, serve for the insertion of a wrench.


=Testing Fuses and Their Component Parts.=--These tests are carried out
as follows:

1. The brass safety stirrups and bushings (time and percussion) are
divided into lots of 500 each. Five per cent of each lot shall be
tested for bending in a hydraulic testing press. The resisting force
of the percussion safety stirrups must be within the limits of 58.68
to 85.77 pounds avoirdupois, that of the brass counter springs between
2.71 to 3.16 pounds avoirdupois, and that of the time safety bushing
between 72.23 to 99.31 pounds avoirdupois. (For fuses for mountain
artillery, from 40.63 to 54.17 pounds avoirdupois.) All the time safety
bushings shall also be subjected on the same press to a compression
test of 72.23 pounds (for fuses for mountain guns, 45.14 pounds
avoirdupois), and only those which have stood this test are finally
considered suitable for the assembly of the fuses.

2. The steel spiral springs shall have no more than 2³⁄₄ turns, and the
upper and lower one must lie in a horizontal plane and approach the
nearest turn. In compressing the springs to 0.33 inch, the springs must
withstand a pressure of from 20.76 to 47.08 pounds avoirdupois, and
after removing the compressive load must resume the dimensions within
the given limits.

3. One-quarter per cent of the completely assembled percussion
arrangement must be tested for determining the correctness of the
locking of the lock bushing with the safety stirrup, with the former in
its settling down position.

4. The counter safety lugs with the base plugs are made up into lots
of 500 each; 5 per cent of each lot, with the inserted percussion
arrangement held in place by bending the lugs on the shoulder of the
lower flange, are tested under load for unbending the catches of the
counter safety lugs. At a load of from 3.61 to 5.42 pounds avoirdupois,
the lugs must release the pellet. The percussion and time safety
bushings and stirrups should be numbered with the number of the lot, in
the order of their manufacture.

5. In order to secure easy turning of the lower time ring by hand, in
setting the fuse, the pressure on the nut in screwing it home should
be determined by readings of an automatic control wrench and should be
between 6.32 and 8.12 pounds avoirdupois.

6. For testing the degree of uniformity of the fuses, they are divided
into lots of not more than 500 each. The testing for the full burning
time of the fuse is to take place on a special apparatus and shall be
determined by a stop-watch; the mean arithmetical difference from the
mean time of burning shall be determined from six tested fuses and
shall not exceed 0.13 second. If a greater difference is obtained, nine
more fuses shall be burned and the mean difference determined from
fifteen separate readings. If the result is more than 0.13 second, ten
more fuses shall be burned and the mean difference determined from all
the twenty-five fuses. If a lot does not fulfill the required test, all
the time rings shall be rejected and the powder in same burned out.

7. In order to determine whether all the component parts of a fuse are
properly assembled and kept firmly in place without moving, each fuse
is shaken by hand and weighed; if the smallest weight of a fuse is not
less than 12.862 ounces avoirdupois (for a mountain fuse, not less than
12.81 ounces avoirdupois) and no displacement of any of its component
parts ascertained, the fuse is set on “grape-shot” and provided with
a protective tin cover; otherwise the fuse shall be taken apart to
determine whether all the parts are inserted in the fuse.

8. The percussion and time detonator caps shall be tested for their
sensitiveness to ignition by being thrown from a height of two feet for
the former, and 1.5 feet for the latter, on the same apparatus as caps
for other fuses. For testing the percussion caps, the lower percussion
arrangement is set, _i.e._, the lock bushing is set until locked with
the percussion pellet by means of the leaves of the safety stirrup, and
then carefully thrust onto the needle of the tail of the stem.

For testing the time detonator caps, the time pellet is first inserted
into the safety bushing; this is done in order to increase the weight
of the pellet, as its own weight is too small and would necessitate
a considerable lifting of the rod of the testing apparatus. In order
to conveniently insert the time pellet within the safety bushing, the
chamber in the top of the stem (the middle one) is bored out, and the
percussion pellet is carefully thrust onto the needle. In testing the
percussion detonator caps, the tail of the stem is screwed into the end
sleeve of the rod of the testing apparatus, and in testing the time
detonator caps the top of the stem is treated in the same manner; in
the latter test, the time rings are first put on the flange of the stem.

For testing the caps delivered to the works manufacturing the fuses in
hermetically sealed boxes (1500 percussion and 2500 time detonator caps
in each lot), ¹⁄₂ per cent of the percussion caps and 1 per cent of
the time caps are selected for this purpose. The caps are regarded as
satisfactory if, in testing the percussion caps, there will not be more
than 1 per cent of cases missing fire or failing to knock out the brass
disk from the base plug; in testing the time caps the number of cases
of non-ignition of the time rings shall not exceed ¹⁄₂ per cent. The
ignited percussion caps must burn the muslin and paper disks placed at
the bottom of the chamber bushing and ignite its powder.

9. Out of a control consignment of 25,000 fuses, 25 shall be selected
for shaking tests on a testing machine during 1¹⁄₂ hour (10 fuses will
be shaken in a horizontal position and 15 in a vertical), in order to
determine the serviceability of the fuses under the most unfavorable
conditions which can be encountered in transporting the shells.


=Equipment of Fuses with Protective Covers.=--The tin cap covering the
fuse is pressed into both grooves on the lateral surface of the flange
of the stem; opposite the holes in the lower groove the cover is staked
in; for waterproofing the fuse, the grooves should be filled with
grease (consisting of 58¹⁄₂ parts of beeswax, 29¹⁄₂ parts of naphtha
grease, and 12 parts of white resin). To conveniently throw off the
cover, a copper wire, stranded of four separate thin wires to preserve
its flexibility, is inserted in the upper groove before putting on
the cover. One end of the wire is slipped through the opening in the
flange and fastened at the bottom; the wire then runs around almost
the whole circumference of the groove, is bent in a right angle in the
direction of the markings on the flange to the top of the cover, where
it is knotted and kept in place by a protruding button pressed out of
the cover. A piece of twilled tape is fastened to the wire, which tape,
in turn, is pasted to the body of the cover.


=Boxing of Fuses.=--Each fuse with cover, after being examined and the
varnish of the tape being found perfectly dry, is carefully wrapped in
wrapping paper; 15 fuses are placed in a zinc box padded at the bottom
with perfectly dry felt, and the spaces between the fuses filled in
with felt or cloth cuttings. The fuses are covered with felt padding
and the cover is soldered to the box. A paper ticket, pasted on the top
of the box, should contain the following information: The number of the
box in the order of manufacture of the fuses in the current year, the
year of their manufacture, the name of the fuses and the quantity per
box, the number of the control consignment and of the daily output, the
time of pressing in the composition, and the time of the ignition test.
The dimensions of the box are: length, 12.15 to 12.20 inches, width,
7.25 to 7.30 inches, and height, 3.11 to 3.16 inches. Four zinc boxes
are put into a wooden box.

The following information should be given on the tag pasted on the
lower side of the wooden box cover: The number of the box in the order
of their manufacture in the current year, the year of the manufacture
of the fuses, the kind of fuses, and the quantity in the box. On the
top of the box a stenciled inscription should be made giving the
number of the box, the quantity and kind of fuses, and the year of
their manufacture. On the side of the box the number of the control
consignment and the year of manufacture should be marked. On boxes
containing fuses with alloy time rings, the number of the box and the
year of manufacture on the cover of the box, as well as the number of
the lot and the year of manufacture on the side of the box, should
be colored red. The weight of one zinc box containing fifteen fuses
should be approximately 16.7 pounds avoirdupois, and the weight of one
wooden box containing four zinc boxes be approximately 90.3 pounds
avoirdupois.


=Instructions for Conducting Firing Tests.=--The following instructions
for conducting firing tests are given in the official specifications:

1. For firing tests, fifty-five fuses should be tested out of a lot of
25,000 fuses or less.

2. The fuses are to be subjected to the following firing tests, using
cast-iron experimental shells: Field fuses will be fired from a 3-inch
quick-firing field gun at a muzzle velocity of 1930 feet per second
and mean pressure of not more than 2400 atmospheres (35,500 pounds per
square inch), and a maximum pressure of not more than 2550 atmospheres
(37,500 pounds per square inch). Fuses from a 3-inch quick-firing
mountain gun, model 1904, are fired at a muzzle velocity of 950 feet
per second and a mean pressure of about 1250 atmospheres (18,400 pounds
per square inch), or from a 3-inch quick-firing gun, model 1909,
at a muzzle velocity of 1250 feet per second and mean pressure of
approximately 1700 atmospheres (25,000 pounds per square inch).

(a) 25 fuses should be tested by firing for percussion action at a
distance of about 4900 feet.

(b) 25 fuses should be tested for firing for time action by setting the
fuse at 52 (mountain guns at 66), or at any other graduation depending
on the atmospheric conditions of the day, in order to obtain a mean
bursting distance of 7000 feet, whereby the mean height of the bursting
should amount to approximately 0.012 of the distance.

(c) 5 fuses should be tested for “grape shot” action without removing
the protecting cover.

(d) Mountain fuses are also tested with 25 shots for time action from a
counter-storming gun at a distance of 3500 feet and a mean pressure of
approximately 1100 atmospheres (16,200 pounds per square inch).

3. A lot of fuses is considered satisfactory if:

(a) In firing for percussion action not more than 2 failures shall take
place, whereby the bursting on ricocheting at the second or further
falls is considered as a failure.

(b) In firing with the fuse set at 52 or at any other graduation,
depending on the atmospheric conditions of the day, in order to obtain
a mean exploding distance of 7000 feet, not more than one failure shall
result, and the probable deflection determined from not less than 20
shots will not exceed 84 feet. In case no failures should occur, it
is permissible in figuring the probable deflection not to take into
consideration one of the shots deflected not more than 420 feet from
the mean point of explosion on the smaller side, or one deflected on
the larger side.

(c) In firing “grape shot,” the mean point of explosion shall not be
farther than 42 feet, and any individual explosion not farther than 140
feet.

(d) In firing for time and percussion action not a single premature
explosion shall take place.

4. A lot which did not satisfy these conditions is accepted for a
second test, if at the first test the following conditions prevailed:

(a) Not more than 3 failures were obtained in firing for percussion
action.

(b) In firing for time action not more than two failures took place,
and the probable deflection did not exceed 98 feet.

(c) In testing for “grape shot” action not more than one failure took
place, the mean point of bursting being not farther than 56 feet and
any individual explosion not more than 175 feet.

(d) In firing for time and percussion action not a single premature
explosion took place.

5. A lot which failed in the first test, but which satisfied the
requirements of Paragraph 4 shall be tested over again, according to
Paragraph 3, on that point only in which the lot failed in testing.

6. In order to be accepted for service, a lot must, at the second
test, give such results that the percentage of failures on time and
percussion action obtained at the first and second firing shall
not exceed in its entirety the percentage which was determined in
Paragraph 3 for corresponding tests. The probable deflections and mean
distances of explosion obtained at the second test for time action,
and in testing for “grape shot” action must satisfy respectively the
requirements as laid down in Paragraph 3.

7. A lot which did not satisfy both tests will not be subjected to
any more tests, and any further action will depend upon the military
authorities.

[Illustration: Fig. 1. Russian Combination Time and Percussion Fuse
(Vickers Type)]


=Action of Fuses at Firing.=--In setting the fuses it is necessary to
bear in mind that each of the 130 graduations of the fuse corresponds
to approximately 140 feet (in fuses for mountain artillery of the
Russian 1904 model to 104 feet) in the change of the firing distance,
the same as the graduations on the sight of the gun. In firing, the
time pellet passes through the safety bushing, expanding the latter,
and falling with the cap on the needle. The detonator cap ignites the
composition of the copper time ring through the vent in stem top and
the hole in upper time ring.

[Illustration: Fig. 2. Body of Russian Combination Time and Percussion
Fuse (Vickers Type)]

When the fuse is set on “percussion”, the transmitting opening of the
lower time ring and the ignition of the flange of the stem are located
opposite the intervening bridges, and the burning of the upper time
composition is not transmitted into the chamber of the fuse. In such a
case the shrapnel continues its movement until striking an obstacle.
At this instant the lower percussion arrangement, releasing itself
from the grip of the lugs of the counter safety catch and compressing
the counter safety spring, approaches the needle, which punctures the
detonating cap; the flame from the latter together with the flame from
the powder of the chamber bushing are transmitted to the bursting
charge in the shrapnel shell. When the fuse is set for “grape shot,”
the transmitting openings in the time rings and the ignition openings
in the flange of the stem are brought so close to one another that the
bursting of the shrapnel must take place on the average not farther
than 42 feet in front of the muzzle of the gun.

[Illustration: Fig. 3. Top and Bottom Time Rings on Russian Combination
Time and Percussion Fuse (Vickers Type)]


=Russian Combination Time and Percussion Fuse--Vickers Type.=--Since
the outbreak of the present war, various fuses have been used on
Russian shrapnel shells. One of the principal of these fuses is the
Vickers type of combination time and percussion fuse shown assembled
in Fig. 1, and in detail in Figs. 2, 3, 4, and 5. While the original
Russian fuse shown in Fig. 4, Chapter I, and described in the preceding
pages, has, up to the present war, been the only fuse used in this
shell, it has largely been replaced by other fuses, because of the
difficulties experienced in manufacturing it. The Vickers type of
fuse is somewhat easier to manufacture and, therefore, has been used
to some extent on Russian shrapnel shells. Another fuse that is now
being adapted to the Russian shrapnel shell is the American combination
time and percussion fuse, Fig. 3, Chapter I, which is also of the
same type as the British fuse described in Chapter XI. The chief
difference in design between the standard Russian and the Vickers
type of combination time and percussion fuse is in the percussion and
concussion arrangements. It will be noticed in Figs. 1 to 5, inclusive,
that the details of the Vickers fuse are much simpler to manufacture.
There is also an absence of the numerous springs in the original
Russian fuse.

[Illustration: Fig. 4. Details of Russian Combination Fuse (Vickers
Type)]

[Illustration: Fig. 5. Details of Russian Combination Time and
Percussion Fuse (Vickers Type)]




CHAPTER IX

SPECIFICATIONS FOR THE MANUFACTURE AND INSPECTION OF RUSSIAN 3-INCH
SHRAPNEL AND HIGH-EXPLOSIVE CARTRIDGE CASES


The following specifications are abstracted from the official
specifications for the Russian brass cartridge cases for 3-inch
shrapnel and high-explosive shells, and contain all the essential
information relating to the requirements in the manufacture and
inspection of these cartridge cases.


=Clause 1. The Rights and Duties of the Inspector.=--The inspector’s
duty consists not only in acceptance of the cartridge cases
manufactured, but also in looking after the methods used in the
manufacture of the cartridge cases, and the brass used for them. In
order to do this, the inspector must have the right of access to any
work and tests referring to the cartridge cases; he must have the
right to enter any shop during any time of the day or night, where the
manufacture of the cartridge cases ordered may take place, _i.e._, the
casting and rolling of the brass, drawing, annealing, finishing, etc.

If the firm with whom the order for the cartridge cases is placed does
not cast brass, but obtains it from other works, the inspector has the
right to visit these latter works in order to ascertain the quality
of the casting (and qualities of copper and zinc), method of cutting
the top and bottom parts of castings, method of rolling, etc. The
inspector’s expenses with reference to his journey to the brass works
in such case must be borne by the firm with which the order for the
cartridge cases has been placed. The minimum number of the necessary
journeys must be determined before the placing of the order.

The firm, which is manufacturing the cartridge cases, must have a
testing machine for the mechanical tests of the metal used for the
cartridge cases; it must also possess a microphotographical laboratory
for the brass (the power of the microscope must be at least 100). The
firm must furnish the inspector with the results of all the chemical,
microscopical, thermal, mechanical and any other tests carried out
on the brass used for the manufacture of cartridge cases, as well as
on cartridge cases themselves. In addition to this, the inspector
must be given the right to use all the firm’s testing plant for the
above-mentioned tests. The inspector must carry out the specified tests
mentioned in the following for the acceptance of the cartridge cases.

Independently of the above, if the inspector thinks it necessary,
for the purpose of ascertaining the qualities and evenness of the
material used for the cartridge cases, as well as the cartridge cases
themselves, to carry out in addition some other trials, the firm must
provide him with all necessary assistance.

[Illustration: Russian 3-inch Cartridge Case]

The firm must place at the sole disposal of the inspector sufficiently
large dry and heated accommodations for carrying out his inspection,
provided with cupboards for his gages; scales must also be provided;
the place must be lighted by electricity, and all necessary power for
the inspection must be provided; gages; and a microscope of from 40 to
50 power.

All gages used for the gaging of cartridge cases must be checked by the
inspector before the beginning of the inspection, as well as during the
inspection. Before submitting the cartridge cases manufactured to the
inspector, the works must submit them to their own examiners. These
examiners must work according to the rules given them by the works, and
prepared in conjunction with the inspector. The firm must provide their
examiners with a separate set of gages manufactured similarly to those
supplied to the inspector.

The inspector has the right to inform the management of the works
of all defects noticed by him in the manufacture of the cartridge
cases, as well as of those defects which occur in the cartridge cases
submitted for acceptance. Finally, he has the right to suggest some
improvements in the manufacture of the cartridge cases; it is left
to the discretion of the management of the works to make use of the
above suggestions, if it is found advisable by them to do so, but the
inspector has no right whatever to interfere with the orders issued by
the management of the works.


=Clause 2. Test Consignment.=--Before beginning the manufacture of the
order, the works must submit a test consignment. The cartridge cases
for test consignment must be manufactured to the approved drawings, and
made of brass according to these specifications. During the manufacture
of the cartridge cases, it is required:

1. That the annealing of the cartridge cases shall be regulated to
prevent any over-heating of the metal.

2. That after the cartridge case is properly formed, the upper half of
the case shall be definitely annealed at a temperature not less than
400 degrees C.

3. That the mechanical quality of the metal in the manufactured
cartridge case shall be in accordance with these specifications.
The method of manufacturing the cartridge cases, as well as the
regulation of the annealing before drawing, is left to the discretion
of the works. The test consignment must be inspected and gaged by the
inspector, and then sent for firing tests. The inspector must measure,
on all cartridge cases in the test consignment, the diameter of the
case near the bottom next to the flange, at a distance of ¹⁄₂ and 1¹⁄₂
inch from the flange.

After firing the first round, all cartridge cases must be inspected
and measured on the same diameters on which they were measured before
firing. The cartridge cases showing the maximum increase of diameter
are to be resized after each round, together with those that are
doubtful with regard to strength, if such re-sizing is allowed by these
specifications. The cartridge cases spoiled during re-sizing must be
replaced by new ones from the same consignment, but these new cases
must be fired the same number of rounds as the old spoilt cases.

The consignment will be accepted:

1. If all cartridge cases after firing are extracted without any
difficulty.

2. If no case shows longitudinal or transverse cracks (or any other
cracks).

The cartridge cases which are supplied together with shell must be
checked and examined in order to ascertain whether the shells are
sufficiently secured in the case.

The test consignment of cartridges must be manufactured at the expense
of the works, but the tests are carried out at the expense of the
government.

In the case of an unsatisfactory test of the first consignment, the
works have the right to submit a second test consignment. In the case
of unsatisfactory results of the tests of the second consignment, the
military administration has the right to cancel the contract.

The inspector has to weigh all cartridge cases of the test consignment,
ascertaining thus the mean weight. In addition, the inspector must
carry out the following test on the cartridge cases of the test
consignment:

1. Chemical composition of brass.

2. Mechanical and microphotographical qualities of metal in the
manufactured cartridge cases.

3. The temperature of the last annealing, _i.e._, the temperature of
annealing before last drawing, temperature before compressing, and
temperature of the final annealing of the finished cartridge case.

The temperatures of annealing must be ascertained by pyrometers.
For this purpose such pyrometers as Ferry may be used, in which the
temperature is ascertained by the color of the object heated.

The methods of manufacture of the order of cartridge cases must be
similar to those used for the manufacture of test consignment. In
case of any alterations in the method of manufacture, the works must
inform the inspector to that effect, and he must report the matter
to the military administration with his opinion on the value of such
alteration in manufacture. It is left to the discretion of the military
administration to allow such alteration or to demand from the works
the delivery of a new test consignment. A firm which has already
manufactured cartridge cases of certain type may be released from the
delivery of a test consignment, provided the methods of manufacture
have not been altered.


=Clause 3. The Acceptance of the Brass.=--The brass used in the
manufacture of cartridge cases must be of the following composition:

  Copper        from 67 to 72 per cent.
  Zinc          from 33 to 28 per cent.

The proportion of other metals must not exceed 0.5 per cent, except
tin, which must not exceed 0.3 per cent.

During the manufacture of cartridge cases in the same consignment, the
variation of copper in the brass must not exceed + 1 per cent, or - 0.5
per cent compared with the usual composition used by the works which
composition must be given to the inspector before the manufacture of
the test consignment. The method of manufacture of brass is left to the
discretion of the works. The only requirements are as follows:

1. The cast ingots must be annealed before first rolling.

2. All rolling must be carried out in the same direction, thus allowing
the top end of the casting always to be distinguishable.

The top or bottom portion of the castings must not be used for the
manufacture of cartridge cases. They must be cut from the ingots by
the works manufacturing the brass, or the blanks for the cartridge
cases must be cut at a certain distance from both ends of the
ingots. On receipt of the brass ingots, the works manufacturing the
cartridge cases must inform the inspector to that effect, giving
him the chemical analysis and the composition of the casting. The
consignment of the brass must be sufficient for the manufacture from
it of the whole consignment of the cartridge cases. At the works which
manufacture the brass, test bars must be cast from the same furnace
and from material of the same quality, melted in a similar manner,
and stamped with the same number as the castings. This number must be
stamped at the bottom of the cartridge case.

The brass used for tests must be submitted to the inspector in bars,
and the cutting of the test disks from the bars must be carried out
under the inspector’s supervision. A few bars are to be used for the
microscopical analysis. The bars of each consignment must be stamped
with a number, which number must be stamped afterwards on the blanks
during all the drawings. This number must also be stamped on the bottom
of the case, as mentioned. These numbers must be put by the inspector
in the report together with chemical analysis of metal, composition
of casting, number of rods delivered, time of delivery, name of brass
foundry by which the brass has been supplied (if the manufacturers do
not manufacture brass themselves), and the number of test disks cut.
For each consignment of cartridge cases manufactured from brass bearing
a certain number, at least one chemical analysis must be made. The
brass not answering to the requirements of the chemical analysis will
be returned to the manufacturer for re-casting.

To insure that the amount cut off from the top and bottom of the rods
is sufficient, the inspector must ascertain from the first consignment
the number of cartridges manufactured, with defects inside as well as
outside, from (1) disks cut from upper end of rod, (2) disks cut from
roller end of rod, and (3) disks cut from the remaining part of rod.
The percentage of cartridge cases with defects, in the above-mentioned
three groups, must not differ materially from each other. The
above-mentioned tests must be carried out from time to time during the
manufacture of the cartridge cases.

The following methods can be used to ascertain that the ends of any rod
are cut off sufficiently:

1. At the center of the rod, cut a piece from the top of the upper
blank; the transverse surface of the piece must be polished and etched
with a weak solution of nitric acid; if the piece cut off from the
top end was not sufficient, the test piece will show, in the middle,
more or less solid black lines, inside of which, under the microscope,
it will be possible to see small microscopical flaws and foreign
substances.

2. The transverse test piece cut in the above-mentioned manner must be
broken in a testing machine; if the top portion was not sufficiently
cut off, the middle of the piece will show ruptures in the metal.


=Clause 4. The Arrangement of the Cartridge Cases in Lots.=--The
cartridge cases for delivery must be arranged in lots. It is desirable
that the cartridge cases in each lot should be manufactured from one
casting of brass metal. If the lots are compiled from the cartridge
cases of different castings, it will be necessary to select cartridge
cases for the control test from all the castings, and the cases left
over from the lots already tested and accepted may be placed in the new
lots without repeated tests.

The dimensions of punch and die for the last drawing must be verified
from time to time. The control of the annealing must be carried out by
means of a pyrometer. The cartridge cases in each lot must be inspected
as follows: 1. Outside inspection. 2. Inspection of dimensions and
weight. 3. Mechanical test of the metal. 4. Firing test.


=Clause 5. Outside Inspection.=--The cartridge cases, before submission
for inspection, must be cleaned inside and outside with sawdust and
sand, or with brushes. The following defects usually occur in the cases.

1. _Cracks._ Longitudinal cracks chiefly occur at a distance of
two or three inches from the flange, and, generally speaking, form
two parallel lines very slightly noticeable on the inner surface.
Transversal cracks, slightly noticeable, generally occur above the
flange at the bottom; they are always on the outside surface and very
seldom penetrate through. Cases with such defects must be rejected.

2. _Ruptures._ These defects usually are on the outer or inner surface
of the cases and show that something is wrong with the metal; cartridge
cases with ruptures are rejected without further consideration. Slight
ruptures found in the corner of the socket for the primer do not affect
the strength of the case and are, therefore, allowed.

3. _Flaws and Fissures._ Cases submitted to the inspector after being
filed and cleaned on the inner surface are rejected. Cases with flaws
and fissures on the inside surface must be submitted to the inspector
separately from the others and the filing of them must be carried out
under the inspector’s supervision. The inspector has to determine to
what extent the flaws are vital. Special attention must be paid to the
flaws on the rim and on the tapered portion.

4. _Scratches._ These are usually due to the punch, or to dirt which
may have been in the punch. Small scratches do not vitally affect
the strength of the cases. Cases with deep scratches are rejected,
especially if on the inner side of the case a very noticeable mark is
seen, extending to the lower part of the case.

5. _Scars._ Small scars which make the surface of the case dull are
allowed. Large scars on the surface giving the appearance of a grained
surface indicate too high a temperature in annealing, and cases with
such scars must be rejected.

6. _Dents._ Dents, if rectified, are allowed on cases if they are not
important; they are not allowed on the conical portion or at the end of
the case.

7. _Goffering._ Goffering on the inner surface of the case is usually
due to the uneven drawing of the metal in the case of very rigid
material; it is due to defects in the uniformity of the material.
Goffering does not appreciably affect the strength of the cases, and
therefore cannot generally be taken as a reason for rejection. A large
amount of goffered cases shows that there are some abnormal conditions
in the manufacturing of the brass or the cases themselves. In such
cases the inspector must point this out to the works, and if the works
will not take measures to remove these defects the goffered cases must
be rejected.

8. _Folds._ Folds of metal are sometimes noticed inside the case at the
bottom and show bad manufacture. Cases with such defects are rejected.

9. _Other Small Defects._ Dents at the bottom, inside, and other small
defects are allowed at the discretion of the inspector.


=Clause 6. Gaging.=--Cases which pass satisfactory outside inspection
must be gaged by means of gages for maximum and minimum allowances. The
dimensions gaged are as follows:

1. All outside diameters of the cases must be gaged with ring gages or
half ring gages.

2. The inner diameter of the end of the case is gaged with calipers.

3. All outside dimensions of the bottom of the case are gaged as
follows:

  (a) Diameters of flanges by half ring gages.

  (b) Thickness of flanges with snap gages.

  (c) Concentricity of the bottom of the case by ring gage.

4. The thickness of the bottom by special gage.

5. Concentricity of the hole for the primer, by special gage.

6. All dimensions of the hole for the primer must be gaged with a set
of corresponding gages.

7. The flatness of the surface, the absence of cuts and hammering of
the metal around the hole for the primer with a straightedge.

8. The outline and the length by a special gage.

9. The thickness of the walls is gaged by means of a snap gage with cut
corresponding to the thickness of the cartridge case at the end, by a
small special gage with pointer for ascertaining the thickness of the
walls as well as the depth of the cleaning away in places near the end
of the case, and by a special gage with pointer for ascertaining the
thickness of the walls along the whole length of the case.

For the purpose of ascertaining that the outline of the cases is
correct, the inspector has the right to select 0.2 per cent of the
cases from the lot, choosing preferably from the rejected cases;
special attention must be paid to the difference in thickness of the
walls at the lower end of the cases. To ascertain the similarity in
weight, all cases must be weighed; the difference from mean weight must
not exceed the limits fixed for each caliber of the cases.

If during the preliminary examination of the cases more than 15 per
cent are found defective, as regards the metal or dimensions, the
inspector has the right to stop the further examination of the cases
submitted, and to ask the firm to re-submit them again. If, after
re-submitting, and during the second examination of the cases, more
than 5 per cent are found unsatisfactory, the whole lot will be
rejected.


=Clause 7. Mechanical Tests.=--In the following paragraphs are given
special conditions for the acceptance of cartridge cases for the guns
of different calibers. As a general rule, the mechanical qualities
of the metal used for cartridge cases must comply with the following
conditions:

1. The rigidity of the bottom and the lower end of the cases must be
sufficient to insure the proper extraction of the cases.

2. The rigidity of the end of the cartridge must insure the proper grip
of the shell, and for the howitzer cases must not show any dents on the
metal.

3. The rigidity of the metal along the whole length of the case must
change evenly, without sudden changes.

During the manufacture of the cases, care should be taken to work the
metal as near as possible to the lower limits of the rigidity of the
metal, as any extra rigidity affects the strength of the case during
firing and in storage.

The mechanical qualities of the cases must, as far as possible, be
alike; they are tested (a) by a breaking test of the metal used for
the cases; (b) by ascertaining that the shell is fixed properly in
the case (a casting may be used for this purpose manufactured to the
dimensions and the weight of the proper shell); (c) microscopical
analysis of the metal; and (d) any other methods at the discretion of
the inspector, as, for instance, by ascertaining the hardness of the
metal, compression of the mouth of the case, etc.

For the tensile test the inspector selects from each lot about five
cases rejected on account of the dimensions; these are cut in halves
for the purpose of ascertaining the thickness of the walls. The number
of cases used for mechanical tests may be increased by the inspector if
it is required by the quality of the material. From each case selected
for the mechanical test, three rings must be cut, one inch wide; one
next to the flange, 1¹⁄₂ inch above it; one from the middle of the
mouth; and one immediately under the conical portion, if such portion
exists; otherwise from the middle of the case. The rings cut in the
above manner must be cut longitudinally and straightened by delicate
hammering with a wooden mallet or by rolling between wooden rollers.
From each strip obtained in such manner two test pieces must be cut
with a distance between marks of 1.97 inch (50 millimeters). The width
of the test pieces must be the same. Ten division marks must be made on
the test pieces, each division being 0.197 inch (5 millimeters). During
the mechanical test, the following data must be ascertained: Breaking
stress, total elongation, and local elongation between all division
marks.


=Clause 8. Firing Proof.=--After the examination of the whole
consignment, the inspector selects some cases for proof by firing. The
inspector chooses for the firing trials those cases which he considers
the least satisfactory. The works have the right to re-examine the
cases selected by the inspector for firing, and remove any case
selected by the inspector; but, in such an instance, all cases with
similar defects are to be rejected, and the inspector replaces the
cases removed by the firm. The works have not the right to remove
the cases selected in the above manner more than twice for each
consignment. The firing proof of the cases must be carried out at any
place selected by the artillery administration, where the cases must be
delivered by the works.

The firing proof must be carried out in a similar manner to the test
consignment, and the submitted consignment is accepted:

1. If all cartridge cases after firing are extracted without any
difficulty.

2. If no case shows longitudinal, transversal or any other cracks, or
ruptures of metal.

If during the firing trials one case shows a crack or is difficult
to extract, the works have the right to review the consignment and
submit for the firing trials a second set chosen by the inspector. In
such instances, the works have no right to remove any case selected by
the inspector for secondary proof; the number of cases selected for
secondary proof as well as the number of proof rounds fired may be
increased. For the acceptance of the consignment, all cases must give
satisfactory results in the second firing test. If the two consecutive
firing proofs will give unsatisfactory results, the artillery
administration has the right to cancel the contract. The firing proof
is carried out at the expense of the government, and the cases normally
used are counted as part of the consignment. The fired cases, after
re-sizing, annealing and inspection, are submitted by the works to the
inspector, and afterwards they must be packed in separate boxes.

The cases required for secondary proof must be at the expense of the
manufacturer.


=Clause 9. Varnishing.=--In case of satisfactory results of firing
proof, the works varnish the cases inside as well as outside. The
varnish must be used evenly. When scratched with a wooden point or with
the finger nail, the varnished surface must not show any impression;
when scratched with a metallic point the varnish must not crumple, and
must not show any cross cracks. The varnish on the cases must not alter
its appearance if placed for twenty-four hours in water, and after
removal from the water and again dry, it must adhere so firmly as not
to be removable under pressure of the finger.

The specific gravity of the varnish must be from 0.9 to 0.94. Brass
strips covered with the varnish must not show any oxidizing action.
After the heating of the varnished strips during 24 hours in the water
bath at a temperature of 167 degrees F., the varnish, when heated, must
not peel off. For the purpose of ascertaining the character of the
reaction of the varnish, 10 cubic centimeters (0.61 cubic inches) of
solvent must be distilled from 100 cubic centimeters (6.1 cubic inches)
of the varnish, and the solvent obtained in this manner, when mixed
with a weak solution of litmus, must not give an acid reaction.


=Clause 10. Stamping.=--The cases must be stamped as follows: On the
top, the number of the consignment of brass; at the left, number of the
consignment of the cases and the year of manufacture; on the right,
the firm’s initials; at the bottom, the inspector’s stamp, which must
be placed after the inspection, and the stamp which means accepted and
which must be placed after the firing proof. The letters and figures
must not exceed ¹⁄₈ inch in height.


=Clause 11. Packing.=--The cases, after being wrapped in paper, are
covered with straw caps and packed in strong wooden boxes. These must
be dovetailed from pine or fir wood, with rope handles and iron bands.
The lids must be fixed with screws. The works have to pack the cases
to the satisfaction of the inspector. To ascertain the accuracy of
packing, the inspector turns over one of the boxes chosen, and after
that the case must not show any dents or any noticeable damage to the
varnish on the cases. Fifty cases are packed in each box.

The boxes must have the following marking:

    Accepted Cases:

  Caliber of Cases
  Name of Works
  Year of Manufacture
  Number of Cases in Lot
  Number of Consignment

    Fired Cases:

  Caliber of Cases
  Name of Works
  Year of Manufacture
  Number of Cases in Lot Fired, but Good for Use
  Number of Consignment


=Condition for Acceptance of Cartridge Cases for 3-inch Field
Guns.=--The test consignment must consist of fifty cartridge cases.
The proof must be carried out from the gun with pressure of about
15.75 tons per square inch (2400 atmospheres). Ten cases are selected
from those showing the maximum increase of diameter and are used for
re-charging; they must be re-annealed after each round; all doubtful
cases must be added to the above-mentioned cases. Each of these cases
must stand eight rounds.

The gaging must be carried out as follows:

                                                    Dimensions in Inches
                                                       Normal    Reject

  1.   Diameter of the case near bottom, gaged with
       half ring gages                                 3.294      3.286

  2.   Diameter of flange, gaged with half ring gages  3.547      3.539

  3.   The outside diameter of the end, gaged with
       half ring gages, and with gage inserted in
       the case                                        3.004      3.000

  4.   The inner diameter of the case                  2.923      2.927

  5.   The thickness of the flange                     0.142      0.134

  6.   The thickness of the bottom, gaged with
       special gage                                    0.157    + 0.030
                                                                - 0.010

  7. The concentricity of the hole for the primer must be gaged with
  special gage.

  8. The concentricity of the flange with reference to the body must be
  gaged with half ring gage, the dimensions of which must be as follows:

    (a) Maximum diameter of flange.

    (b) Maximum diameter of the case at bottom.

    (c) Maximum thickness of the flange.

  9. The outline and the length of the case must be checked by special
  chamber gage. The allowance for length must be ± 0.010 inch.

  10. The gaging of the hole for the primer is carried out by the
  following gages:

    (a) Screw gages, normal and reject.

    (b) Normal gage which is used for the gaging of the whole diameter
    and the depth of the hole for the primer, normal and reject.

    (c) Reject gage for the flange of the primer.

    (d) Reject gage for the thread.

    (e) Reject gage for the plain surface of the hole.

    (f) Normal and reject gages for the thickness of the hole for the
    flange of the primer.

    (g) Normal and reject gage for the depth of the plain portion of
    the hole.

    (h) Gage for the ignition hole.

  11. Normal and reject gage for the height of the boss for the primer.

  12. Gages, compasses and special gages for the thickness of the
  walls and for the depth of filing of the inner as well as the outer
  surfaces.

  13. Straightedge for gaging the bottom surface of the case.

The difference in the weight of cases from mean weight must not exceed
± 3 ounces.

The test pieces subjected to the tensile test must show the following
breaking stress:

(a) At the ends, 48,000 to 57,000 pounds per square inch, with local
elongation not less than 60 per cent.

(b) Next to the flange, from 64,000 to 85,000 pounds per square inch.

(c) Next to the conical portion, not less than 52,500 pounds per square
inch.


=Firing Trial.=--For the firing trials, thirty cartridge cases must be
selected. These cases must be measured and must pass a similar test to
that of the test consignment, with the following exceptions.

1. Only five cases are taken for re-proving, including cases showing
the maximum expansion, and those doubtful with reference to their
strength.

2. The cases are to be fired five times.

During the firing of the secondary proofs, as well as during the
firing of the cases selected from the lots entirely consisting of the
defective cases, the number of cases as well as the number of re-tests
may be increased to the number fixed for the test consignment.


=Specifications for Primers.=--The charge primer consists of brass
body, detonator, bush, brass anvil, a charge of gun powder (not
polished with graphite), a disk of saltpeter-soaked tissue paper, four
powder cakes, disk of saltpeter-soaked muslin, disk of parchment, and
a brass disk bored in the center and coated outside with thick shellac
varnish mixed with cinnabar.


=Detonator.=--The detonator consists of a small copper cap containing a
charge of 0.275 grain of the detonator composition, covered by a thin
paper parchment disk and compressed with a pressure of 125 pounds.
The thickness of the parchment is between 0.002 and 0.0025 inch. The
surface of the parchment facing the composition is coated by a thin
layer of fluid shellac varnish composed as follows: 15.12 gallons of 95
per cent alcohol and 20 pounds of shellac.

The detonator composition contains 50 per cent fulminate of mercury, 20
per cent chlorate of potassium and 30 per cent glass ground to dust and
sifted through a sieve No. 100 (100 meshes to 1 inch). To this mixture
is added 0.25 per cent of tragacanth gum and a trace of gum arabic.
The composition is placed in the cap while moist. After compression
the detonator is dried for ten days at a temperature of 88 degrees F.,
and twenty days at 111 degrees F. Then the exterior surface of the
parchment disks is coated with a thick varnish composed of 0.891 gallon
of 95 per cent alcohol, 2.75 pounds of shellac, and 0.5 pound of resin.
The varnished detonators are dried at room temperature for five or
six days, and then undergo a final examination, in which the defective
caps will be rejected. The caps, when ready, must have even wedges, no
rents, cracks, dents or such like defects, and the parchment disks must
be placed concentric with the edges of the caps.

Out of a lot representing a day’s output (about from 10,000 to 15,000)
of detonators, twenty-five are set aside without selection, for
testing under a drop weight of 13.65 ounces, falling from a height of
3.94 inches. These must not show a single failure. If a day’s output
of detonators does not answer that condition, it undergoes, after a
supplementary drying, a second test in double quantity. Any lot of
detonators that does not stand this test will be rejected and burnt out.

The tissue paper and muslin disks are soaked with a 10 per cent
solution of saltpeter. The powder cakes are compressed gun powder, not
polished with graphite, and have a diameter of 0.748 inch, a height of
about 0.120 inch, and weigh from 21.95 to 23.32 grains each.


=Charging Primers.=--The charging of primers is preceded by the
examination of their bodies and other parts. The charging is done in
the following order: The detonator is placed in the bush which is
screwed onto the end into its seat and then nipped in two places in
order to prevent its becoming unscrewed. The anvil is then screwed into
its seat, so as to press tightly on the detonator composition, without,
however, cutting the parchment disk. To inspect the proper screwing
in of the anvils, 30 primers are set aside out of every 300, and from
those the anvils are screwed out and the detonators examined. The
parchment disks must bear clear marks of the anvils, without being cut
through.

In properly fitted primers the anvils are prevented from becoming
unscrewed by nipping them in two places. A charge of from 10.286 to
10.972 grains of powder is placed in the groove between the hose and
the internal surface of the body of the primer. This charge must
fill the groove to the brim. The powder is now covered with the
disk of tissue paper soaked in saltpeter. On the top of it will be
placed four powder cakes, which will be covered first with a disk of
saltpeter-soaked muslin, then with a parchment disk and lastly with
a brass disk bored in the center, after which the upper edge of the
primer is closed in, this operation being carried out in three stages.
After the first pressing, a proper position is given to the disks
inside the primer; after the third (final) pressing the primer is to
be gaged. The upper side of the brass and parchment disks is varnished
with thick shellac mixed with cinnabar.

After having been dried in the shop for 24 hours, the primers are
packed in cardboard boxes. Two such boxes, (50 primers in each) are
sealed hermetically in zinc boxes. The proper hermetic soldering of
some boxes chosen at random will be tested. Eight zinc boxes are packed
in one wooden box, which will thus contain 400 primers.


=Inspection of Primers.=--Bodies and other details will be manufactured
of brass, the composition of which will be left to the discretion of
the works, but on the express condition that the primers will comply
with all requirements stipulated. The best results have been obtained
when the metal contained from 67 to 74 per cent of copper, and from 33
to 26 per cent of zinc.

Before beginning the manufacture of the order, the works with which the
order will be placed must deliver a test consignment consisting of 100
primers. The test consignment of primers after being charged must be
subjected to a firing trial. The conditions of this trial are similar
to those used for the trials of the complete order. The order must be
submitted in lots of 25,000 each.

The gaging of dimensions at the works manufacturing the primers must
be carried out after each separate operation of manufacture, for which
approved gages and control gages must be used. All the gages must be
manufactured by the works, with which the order for the primers is
placed, with the exception of the gage nut used for the gaging of the
outer thread and the check screw for same. The last mentioned gages
must be handed over to the primer works by the proper authorities.

The primers, before being charged, will be assembled at the works which
manufacture them, _i.e._, bushes and anvils are screwed in, and the
primers are delivered to the explosive works in such condition. After
the completion of the manufacture of a lot of 25,000 primers, 1000 of
them, chosen at random during the manufacture, will be sent to the
explosive works for inspection, for testing the rigidity of the metal,
and for preliminary tests of the metal by firing.

If, during the trial for the rigidity of the metal carried out by the
compression of 50 primers chosen at random, more than 5 per cent show
ruptures, the complete lot of 1000 primers will be returned to the
manufacturers.

In the case of satisfactory results of firing trials, the remaining
24,000 primers will be delivered to the works intrusted with the
charging.

If, after partial examination of a lot (not less than 1000 primers),
more than 10 per cent of primers will be rejected in accordance with
the following two paragraphs, the further inspection will be stopped at
the charging works, and the whole lot will be returned for resorting.

When inspecting primers, the following defects are not allowed:
ruptures, blow-holes, fissures, flaws, sandy surface, dirt, oil, dust,
shavings, dents on the bottom surface of the flange, dents at the
bottom of the charge chamber, and considerable crumbling of threads
(more than one-fourth of a thread). The examination of the bottom
surface for evenness must be carried out by spinning the primers on a
polished steel plate. The primers which will not spin must be rejected.

The primer chambers must be varnished. The anvils must not show any
flaws and fissures at their striking edge and at the threads. The
striking edge must not be sharp, to prevent the cutting through of the
parchment disks of the detonator; generally speaking, the anvil and the
bush must also answer all the requirements of the preceding paragraph.


=Gaging.=--One hundred primers complete from each lot must be gaged.
Special attention must be paid to the following points:

(a) All primers to be screwed into gage without being specially loose.

(b) The thickness and the outer diameter of the primer head must not
exceed the specified maximum dimensions, thus securing the proper fit
of the primer flange in its seat in the cartridge case.

(c) The height of the boss inside the primer must be strictly in
accordance with the allowance given.

(d) The inner thread of the boss must be strictly in accordance with
the gage.

(e) The seat for the detonator and the hole in the bush must be correct
and in accordance with the gage.

(f) The thickness of the bottom of primer (0.067 to 0.077 inch) must be
in accordance with the gage.

The anvils and bushes must screw and unscrew easily, without being
loose and must be interchangeable. After charging, all primers will
be inspected with regard to their height, and gaged outside. In case
of unsatisfactory results in gaging (rejected primers exceeding 3 per
cent) an additional 100 primers must be chosen for the same purpose,
and in case the results are the same, the whole lot will be returned to
the works manufacturing the primers for resorting.


=Firing Trials.=--Fifty primers out of 1000 delivered from a lot of
25,000, after being charged, are tested with reference to the quality
of the metal, by firing with increased charge at a pressure of 2400
atmospheres (15.75 tons per square inch). These primers, after the
test, should not show any breakage (after being unscrewed) through
cracks and flaws, the presence of which would mean that the gas escaped
through the base of the primers. The escape of gases leaving a residue
between the side surfaces of the primer flanges and their seating is
allowed on not more than 30 per cent of the primers subjected to firing
test from new cartridge cases; in the case of using fired cartridge
cases, no attention must be paid to the presence of the above-mentioned
residue.

Non-through cracks are allowed on not more than 2 per cent of tested
primers; in the case of a larger percentage, but not exceeding 4 per
cent, the whole lot must be resorted and retested. The recurrence of 2
per cent of non-through cracks in the second test may not be taken as a
reason for the rejection of the whole lot; 50 primers must be used for
the second test. In the case of the absence of above-mentioned defects,
only those primers will be considered satisfactory which, after firing,
can be removed from the cartridge case by hand or by an ordinary
spanner.

The serviceableness of the primers is determined by firing 50 primers
chosen at random from the complete lot of 25,000 charged primers. The
conditions just laid down hold good for this trial also. In addition
to this, no complete misfire must occur; not more than two primers
may misfire once each, with lock in proper order. (Before firing, the
tension of the main spring and the protrusion of the firing pin must be
verified.) A second test may be carried out if during the preliminary
test defects occur. The second test must be carried out on double the
number of primers taken at random, _i.e._, on 100 primers. During
second test the same conditions as laid down for the first test hold
good. Primers passing successfully the first or second firing tests are
accepted for the service. A lot of charged rejected primers must be
destroyed and the metal scrapped.

In addition to the firing tests, the following test must be carried
out by the works intrusted with the charging of primers to determine
the correctness of charging: 1. One per cent of a day’s output must be
tested under a drop weight of five pounds falling from a height of 0.39
inch with flat firing pin 0.25 inch in diameter; during this test no
primer must detonate. Primers having passed this test and not showing
any noticeable mark on the base must be recharged and added to the lot.
2. When testing 0.5 per cent of each day’s output under a drop weight
of five pounds, falling from a height of 5.9 inches, with firing pin of
an approved pattern, no primer must fail to explode.




CHAPTER X

SPECIFICATIONS FOR BRITISH 18-POUNDER QUICK-FIRING SHRAPNEL SHELL


The following paragraphs, abstracted from the official specifications,
give all the information contained in these specifications relating to
the manufacture and inspection of the British 18-pounder, quick-firing
shrapnel shell.


=Body.=--The body of the shell is made of cast or forged steel of
the best quality for the purpose, turned or ground to the form and
dimensions, and having the edge of the base rounded. If made of cast
steel, the casting must be clean, of uniform transverse thickness,
free from flaws, blow-holes, and other defects. The use of chaplets is
prohibited. If made of forged steel, the body must be forged hollow,
and free from forging marks and flaws. Should the shells be subjected
to heat-treatment, this must be carried out in batches consisting of
shells of the same cast. An undercut groove, with two projecting waved
ribs, will be turned on the body. Three chisel cuts may be made across
the waved ribs in the groove for the driving band, at an angle to the
longitudinal axis of the projectile to allow the air in the channels
between the ribs to escape when the band is being pressed on. The top
is threaded to receive the socket, and a groove for the fuse cover
provided. The steel body alone must weigh 6 pounds 5 ounces 12 drams,
plus or minus 2 ounces.


=Driving Band.=--The driving band is made from a ring of drawn or
electro-deposited copper, pressed into, and in contact with, the bottom
and undercut of the groove in the shell all around, and accurately
turned to the form required. The weight must be 4 ounces 12 drams, plus
or minus 2 ounces.


=Socket.=--The socket is made of composition metal, known as Class “C,”
threaded externally below the shoulder to fit the body, and internally
to receive the fuse, the bottom being bored to receive the top of the
central tube. The junction of the socket and central tube is soldered
to prevent the resin getting into the tube and socket. A hole is to be
bored in the side, threaded and fitted with a steel fixing screw. The
weight must be 8 ounces 8 drams.


=Central Tube.=--The central tube may be made of brass, copper, delta
metal, or gun metal. The lower end is to have a shoulder to rest on,
and to be threaded to enter the steel disk, the bottom being reduced in
diameter to fit the neck of the cup. Weight, 2 ounces 12 drams.

[Illustration: Fig. 1. Construction of British 18-pounder Quick-firing
Shrapnel Shell]


=Steel Disk.=--A steel disk, of the form shown in Fig. 2, will rest
on the shoulder in the bottom of the body, a hole being bored and
threaded through the center of the disk to receive the central tube.
Weight, 9 ounces 8 drams.


=Tin Cup.=--The cup in the base of the shell to contain the bursting
charge will be made of tinned plate to the form and dimensions shown in
Fig. 2, the parts being soldered together. Weight, 1 ounce 12 drams.


=Gages.=--Contractors may send their gages at any time to the chief
inspector, Woolwich Arsenal, London, England, to be checked and
compared with the standard gages.


=Screw Threads.=--The screw threads must, unless otherwise stated, be
of the British standard fine screw thread, and conform to the chief
inspector’s standard gages.


=Preliminary Examination of Contractor’s Work.=--The bodies, after
completion of machining, will be submitted at the contractor’s works,
to an inspector, for preliminary examination. Bodies made of cast steel
must also be submitted for a hydraulic test under a pressure of 100
pounds per square inch. Any shell which shows the slightest leak, or
fails to satisfy the conditions, will be rejected.


=Assembling.=--The tin cup, steel disk, and central tube are to be
placed in position and the shell filled with mixed metal bullets, 41
per pound (composed of seven parts of lead and one of antimony), the
interstices between the bullets being filled with resin, which must be
perfectly pure, and filtered when in a liquid state through a sieve
having 32 meshes per inch. The socket is then screwed onto the body as
tightly as possible, the threads having been previously coated with
Pettman’s cement or red lead.


=Marking and Plugs.=--The shells are to be marked on the side, above
the driving band. Plugs for the protection of the fuse holes in transit
will be supplied, free of charge, on demand, by the ordnance officer to
whom delivery is to be made.


=Delivery.=--(a). The shells will be covered with a thin coating of
vaseline or other similar anti-corrosive grease, which must be of
such a nature as not to interfere with the gaging, and they will
then be delivered unpainted, for inspection and proof. The shells
must be perfectly cleaned out, empty, complete in every respect, and
dry internally. (b). Such marking as may be necessary to identify
the steelmaker’s cast number, and, in case of heat-treatment, the
batch number, must be maintained by the contractor upon every shell
throughout manufacture. (c). The shell must be delivered in lots for
purposes of proof. A lot for this purpose will consist, as far as
possible, of shells of the same cast, and, when heat-treatment is
employed, of shells of the same batch number, and must not contain more
than 121 shells. (d). When the number of shells in a cast or batch is
less than 100, two casts or batches may be grouped together for this
purpose.


=Main Examination after Delivery.=--(a). Any shell of a lot which fails
to pass the chief inspector’s gages, or fails to satisfy the chief
inspector of its serviceability, will be rejected. (b). If at any time
during the examination it is found that defects of any nature, other
than errors of machining, which involve rejection of defective shells,
amount to 5 per cent of the number of the shells in the lot, the “lot”
will be rejected, (c). One or more shells selected from the lot will
be taken to pieces, and the body broken, if necessary, to ascertain
that the details of manufacture and component parts are correct, and
that the material is sound. Should they be incorrect, or the material
unsound, in any particular, the lot will be rejected. The driving
band will be cut out, and should it appear not to have been pressed
thoroughly home into the undercut and groove throughout, the lot will
be rejected. (d). If, at any time during the examination of a lot,
it is found that 5 per cent of the shells in the lot depart from the
approved design, further examination of the lot will be suspended. The
whole of the lot must be re-examined by the firm and those shells which
are incorrect eliminated. Those shells in which the departure can be
rectified may be brought to the approved design by the firm. The lot
may then be re-submitted.


=Tests.=--At least 1 per cent of the shells of every cast will be
subjected to tensile tests. Test pieces will be cut from the shell
blank, or from the finished shell at the option of the chief inspector,
and must be capable of standing the following minimum tests:

  +-------------------+-------------------------------------+
  |Tenacity, Tons per | Elongation in a Test Piece 2 Inches |
  |   Square Inch     | in Length, or such Piece as can be  |
  + -------+----------+ cut from the Shell, provided that   |
  | Yield  | Breaking |                                     |
  | Point  | Stress   |      Length / √Area = 4             |
  +--------+----------+-------------------------------------+
  |   36   |    56    |           8 per cent                |
  +--------+----------+-------------------------------------+

If any one or more of the conditions in this clause are not complied
with, the lot, or lots, of shell affected, will be rejected, and must
not be re-submitted. The contractor will supply, free of charge, the
necessary “Class C” metal for testing, if requested by the chief
inspector to do so. The pieces should not be less than 7 inches in
length, nor less than 1 inch in diameter, and will be required to stand
the following test:

  +-------------------+-------------------------------------+
  |Tenacity, Tons per |                                     |
  |   Square Inch     |                                     |
  +--------+----------+ Elongation in a Test Piece 2 Inches |
  |Yield   | Breaking | long and 0.564 Inch in Diameter     |
  |Point   | Stress   |                                     |
  +--------+----------+-------------------------------------+
  |   6    |    12    |          10 per cent                |
  +--------+----------+-------------------------------------+


=Proof.=--(a). A percentage of the shell will be fired for recovery
from an 18-pounder Q. F. gun, with such a charge as will give a chamber
pressure not less than 15 tons per square inch. Should the shell so
fired set up above the high diameter of body, or break up in the gun,
or should any portion of the driving band separate from the shell
before first graze or impact, or should the recovered shell show that
the shock of discharge had distorted the disk supporting the bullets,
or cause such alteration of the internal parts as would interfere with
the correct action of the shell, or should any of the components be
incorrect, the lot will be rejected, provided always that the pressure
did not exceed the specification proof pressure by 0.5 ton. If the
pressure did exceed this limit, a second proof must be taken at the
government’s expense before the lot is rejected. The pressure of the
round, if not taken, will be assumed to be that of the last round fired
with the same charge in which pressure was taken. Further, should the
shell be reported unsteady in flight, and be found on recovery to be
without its driving band, or with the driving band loose or slipped in
its seating, then the driving band of a similar number of shells to
that taken for firing proof may be cut out to ascertain whether they
have been properly pressed on; if they have not been pressed down to
the satisfaction of the chief inspector, the lot will be rejected. If
found correct, such shells will be rebanded by the contractor free of
charge.

(b). The shells fired for proof may, after recovery, be broken to
ascertain the soundness of their material. Should any of the material
be unsound in any respect, the lot will be rejected.

[Illustration: Fig. 2. Details of British 18-pounder Shrapnel Shell]



=Re-submission.=--(a). A rejected lot must not be re-submitted unless
the rejection is due to failure of the driving band, or to rectifiable
gaging defects. (b). Shells put out at any period of inspection
for remediable defects may be re-submitted for further examination
after the defects have been rectified. It is to be understood that
the examination of such shells at that time will be incomplete, and
that they are liable to rejection after rectification. (c). If the
contractor wishes to re-invoice a lot rejected for failure of driving
bands, he must remove the shells and re-band them before they are
again submitted, (d). Rejected shells will, if considered necessary,
be marked with a small rejection mark, so that they can be readily
identified if redelivered.


=Replacement of Proof.=--The contractor will be required to replace,
free of charge, all shells expended in proof and examination, which,
whether fired or otherwise tested, will be the property of the
government.


=Packing.=--All packages are to be so marked that the goods contained
therein may be readily identified with the invoice. Unless it is
specified in the contract that the packing cases or other packing
material are to become the property of the war department, they will
remain the property of the contractor, who is responsible for their
removal.

Should they not be removed within two months of the acceptance at the
stores, they will be disposed of, and under such circumstances the
contractor will not be entitled to make any claim for compensation. The
packing cases must be marked “Returnable” or “Non-returnable.”


=Inspection.=--The shells may be inspected at any time during
manufacture by, and after delivery will be subject to testing by, and
to the final approval of, the chief inspector, Royal Arsenal, Woolwich,
England, or an officer deputed by him. In cases of defects occurring in
manufacture which necessitate repairs, the contractor shall bring the
same to the notice of the inspecting officer, and shall obtain from him
written authority to proceed with such repairs as may entail patching,
burning, electric welding, or other similar processes.

WEIGHT OF 18-POUNDER SHRAPNEL SHELL PARTS

                                       Weights (avoirdupois)
    Part                               Pounds  Ounces  Drams
  Steel body                             6       5      12 }
  Driving band                                   4      12 } ± 2 oz.
  Metal socket                                   8       8
  Steel disk                                     9       8
  Brass tube                                     2      12
  Tin cup                                        1      12
  Bullets, about 327 of alloyed metal,
   41 per pound                          7      14      13¹⁄₂
  Resin                                         13      11
  Total weight empty (unpainted)*       16      13       8¹⁄₂ ± 11 drams
  Bursting charge                                2       8
  Paint                                                  5¹⁄₂
  Fuse                                   1       7      10
                                       --------------------------------
  Total weight                                  18       8 ± 5 drams

  * To regulate weight of shell, a few buckshot may be used.


=Plug for Fuse Hole.=--The plug is to be made of a copper alloy, and to
the form and dimensions shown on the drawing, threaded externally on
the body, and a square recess, tapered, is to be formed in the top. The
screw threads must, unless otherwise stated, be of the British standard
fine screw thread, and conform to the standard gages of the chief
inspector, Royal Arsenal, Woolwich, England. Contractors may send their
screw gages to the chief inspector, to be compared with the standard
gages.

Any plug of a delivery which fails to pass the inspecting officers’
gages, or shows flaws or sponginess on the surface, or fails to
satisfy the chief inspector, Woolwich, as to its serviceability, will
be rejected. If at any time during the examination it is found that
defects of any nature, other than errors of machining, which involve
rejection of the defective plugs, amount to 5 per cent of the number of
plugs in the delivery, the whole order will be rejected. If at any time
during the examination of a delivery it is found that 5 per cent of the
plugs in the delivery will depart from the approved design, further
examination of the plugs will be suspended; the whole of the delivery
must be re-examined by the firm, and those plugs which are incorrect to
design eliminated. Those plugs in which the departure can be rectified
may be brought to the approved design by the firm. The delivery may
then be re-submitted for examination. The contractor will be required
to replace free of charge all plugs expended in test and examination,
which will become the property of the government.




CHAPTER XI

SPECIFICATIONS FOR BRITISH COMBINATION TIME AND PERCUSSION FUSES


The following specifications, abstracted from the official requirements
relating to British “Mark I” (No. 85) combination time and percussion
fuses, give the general information required in the manufacturing and
inspection of these fuses. These specifications, in conjunction with
the very complete illustrations, Figs. 1 to 6, inclusive, of the design
and details of the British fuse, give all the essential data required.


=Components.=--The fuse consists of the following parts: Body, top and
bottom composition rings; cap with set-screw; base plug with screw
plug; time detonator pellet in two parts; percussion pellet with sleeve
and firing pin; detonators; four spiral springs; brass and steel pins;
onion skin paper; unbleached muslin; felt cloth and brass washers;
brass and tin-foil disks; suspending ring for time pellet; and onion
skin paper patches.


=Metals.=--The body and composition rings are to be made of bronze or
metal known as “Class B;” the time detonator pellet and percussion
pellet to be of hard-rolled brass; the percussion firing pin pivot,
of steel, phosphorized or blued; the time and percussion firing pins,
of bronze or “Class B” metal; all other parts of the fuse, except
where otherwise stated, of metal “Class C,” or hard-rolled brass. The
contractor must supply the necessary metal for testing, free of charge.

Metals designated by “classes” are copper alloys, the compositions of
which are left to the discretion of the makers providing the metals
conform to the above tests.

Before proceeding to manufacture, the material must be submitted to the
inspecting officer for mechanical test. When practicable, test pieces
should not be less than 7 inches in length nor less than 1 inch in
diameter, and will be required to stand the following minimum tests:

  +------------------+--------------------+-----------------------------+
  |                  | Tenacity, Tons per | Elongation in Per Cent in   |
  |                  |    Square Inch     |   such a Test Piece as can  |
  |      Metal       +---------+----------+   be furnished, provided    |
  |                  |  Yield  | Breaking |   that                      |
  |                  |  Point  | Stress   |   Length / √Area = 4        |
  +------------------+---------+----------+-----------------------------+
  |Bronze            |   13.5  |    27    |             20              |
  |Class “B”         |   12    |    20    |             30              |
  |Class “C”         |    6    |    12    |             10              |
  |Hard-rolled Brass |    6    |    12    |             10              |
  +------------------+---------+----------+-----------------------------+


=Body.=--The body is to be turned all over, and threaded externally at
the upper and lower ends, a bevel being formed at the junction of the
stem and the flange. The stem is to be bored, and a hole drilled at the
bottom of the bore to receive the time firing pin. The upper surface of
the flange is to be grooved. The interior is to be bored out to form a
chamber for the reception of the percussion arrangement and threaded
for the base plug; a hole is to be bored and threaded at the bottom of
the bore to receive the percussion detonator holder. An annular recess
is to be made for the magazine. Communicating holes are to be drilled
as follows:

  (a) At an angle to the top surface of the flange.
  (b) Vertically from the magazine recess.
  (c) Horizontally at the top of the detonator recess.
  (d) At an angle to join (b) and (c).
  (e) At an angle from outside to bottom of recess in stem.

Holes (c) and (d) are to be closed by plugs driven in and secured by
punch stabs. Two slots are to be cut in the flange as shown in Fig.
2, and an elongated hole made to receive a stop pin, which is to be
secured by a small pin, driven in. A setting mark is to be cut on the
edge of the flange.


=Top Composition Ring.=--The ring is to be turned all over, and bored
to fit the stem of the body. A groove is to be formed in the under
side for the composition, and a recess made as shown in Fig. 2, three
holes being drilled from the upper surface into the recess. A hole is
to be drilled through the ring between the ends of the composition
channel, and recessed. A recess is to be formed in the bore, from which
a flash hole is to be drilled at an angle communicating with one end
of the composition channel, a vertical escape hole being made from the
top surface to the flash hole. An indicating mark is to be made on the
outside of the ring. Two holes are to be bored between the ring and
the stem of the body, into which pins are to be inserted to retain the
ring in position. The ring is to be made 0.020 inch thicker than the
dimension given on the drawing, and faced off to thickness after powder
is pressed into the groove.

[Illustration: Fig. 1. British “Mark I” (No. 85) Combination Time and
Percussion Fuse--Modified Form of American 21-second Fuse]


=Bottom Composition Ring.=--The ring is to be turned all over and
bored to fit the stem of the body, the upper surface being grooved. A
groove is to be formed in the under side for the composition, and an
annular recess made, three holes being drilled from the upper face into
the recess. A hole is to be drilled in the ring from the under side
between the ends of the composition channel. An escape hole is to be
drilled, at an angle, from the end of the composition channel to the
annular recess, and a recess made to receive the closing disk. A hole
communicating with the groove and the escape hole is to be drilled at
an angle to the top surface to receive a powder pellet. A hole is to
be drilled and recessed for a setting pin, which is to be secured by a
small pin driven in. The ring is to be graduated from “0” to “21.2;”
each division, after the first, is to be sub-divided into five parts.
A line to denote safety position is to be marked. The marking is to be
blackened with japan black thinned with spirits of turpentine, except
the mark denoting the safety point, which is to be colored red.


=Cap with Set-screw.=--The cap is to be machined all over, and recessed
internally to receive the time detonator pellet. The lower part of the
recess is to be threaded to screw over the stem of the body. Two slots
are to be made in the cap to receive a key, and a hole is to be drilled
through the side and tapped to take a brass set-screw. A groove is to
be made near the top, which is to be partially closed by spinning over
the edge. Four escape holes are to be drilled at an angle from the
recess on the under side, into the groove.


=Base Plug.=--The base plug is to be threaded externally to fit the
bottom of the body. Two holes are to be drilled in the under side to
facilitate assembling, and a central recess formed with a seating to
receive a brass washer with a muslin disk. Six holes are to be drilled
at an angle from the upper surface into the lower recess, and a hole
drilled and tapped in the bottom to take a screw plug. This plug is to
be threaded externally to fit into the bottom of the base plug.

[Illustration: Fig. 2. Details of British Combination Fuse]


=Time Pellet and Detonator.=--The pellet is to consist of two parts,
which are to be turned and bored, the parts being screwed together
to secure the detonator. A screwdriver slot is to be made in the top
surface, and a seating formed on the outer surface for the suspension
ring. The detonator is to be turned all over and recessed, four fire
holes being drilled through into the recess. The recess is to be
coated with non-acid paint and charged with 0.45 grain of the following
composition (giving parts by weight):

  Glass                  50
  Fulminate of Mercury   40
  Chlorate of Potash     20
  Sulphide of Antimony   30
  Shellac (dry)           2.8

The ingredients are to be thoroughly pulverized, excepting the
fulminate, mixed dry, and then covered with alcohol. The fulminate will
then be added and the whole thoroughly mixed. The composition is to be
covered with a brass disk secured by shellac. The recess in the plug is
to be coated with a composition of shellac and rosaniline and filled
with 1¹⁄₂ grain of shrapnel powder compressed with a total pressure of
60 pounds. The detonator is to be inserted in the holder, and secured
in place by the screw plug, the two being locked together by a small
brass pin.


=Percussion Pellet.=--The percussion pellet is to be machined all over,
two holes being bored in the upper surface and a slot cut to receive
the firing pin. Two holes are to be drilled at right angles to the slot
and parallel to the flat surfaces, one to receive the pivot for the
firing pin and the other for the centrifugal bolts. The sleeve is to be
machined all over, and is to be a driving fit on the pellet. Two spiral
springs and two small pellets, and a pivot pin for the firing pin, are
to be provided. All parts, except the pivot pin, are to be tinned all
over. The parts are to be assembled, and a hole drilled into the sleeve
and pellet, and a small brass pin driven in.

[Illustration: Fig. 3. Details of British Combination Fuse]


=Percussion Detonator and Holder.=--The percussion detonator is to
be turned and recessed on both sides, two flash holes being drilled
between the two recesses. The smaller recess is to be charged with 0.45
grain of the following composition (the figures giving parts by weight):

  Chlorate of Potash     43.19
  Sulphide of Antimony   21.5
  Sulphur                 7.5
  Glass                  10.5
  Shellac                 1.7

The ingredients are to be thoroughly pulverized and mixed dry. Alcohol
will be added to dissolve the shellac. The detonator will be formed by
pressing the mixture, while in a plastic state, into the recess. On
the evaporation of the alcohol the composition should adhere strongly
to the metal. A brass disk, 34 in Fig. 5, is to be secured over the
composition with shellac. The larger recess is to be varnished with
a composition of shellac and rosaniline, and 4 grains of shrapnel
powder compressed into it with a pressure of 127 pounds and covered
with a disk of tin foil, shellacked on. The holder is to be threaded
externally to fit in the body, and recessed to receive the detonator, a
central hole and two key-holes being made.


=Pellets.=--The powder pellets are to be made to the shapes shown in
Fig. 5. Pellets 33 and 35 are to be made from compressed unglazed black
powder, with clearance holes as shown; pellets 32 and 36 are to have
the clearance holes filled with 0.05 and 0.02 grains, respectively, of
gun cotton.


=Percussion Springs.=--The springs used in the percussion plunger
must be made to the form and size shown in Fig. 5, and tinned. The
percussion safety pin spring (21) is to be made from 0.012 inch
diameter brass wire, tinned, and wound so as to give a free height of
0.150 inch ± 0.030 inch, and at such a spacing as to give 44 coils per
inch. The percussion restraining spring (30) is to be made from 0.015
inch diameter brass wire, tinned, and wound so as to give a free height
of 0.500 inch ± 0.050 inch, and at such a spacing as to give 36 coils
per inch. This spring is to have a maximum resistance of 1.65 and a
minimum of 1.5 ounce at an assembled height of 0.370 inch.


=Suspending Ring.=--The suspending ring for time detonator pellet is
to be made of brass wire. The ring is to be of such strength that when
tested with steel counterparts of the stem and pellet, the latter is
forced through the ring with a deadweight load of from 69 to 77 pounds.

[Illustration: Fig. 4. Details of British Combination Fuse]


=Cloth Washers.=--The cloth washers are to be made from waterproofed
felt cloth, with holes cut in them. The body and graduated time train
washers 16 and 17, respectively, which are shown in Fig. 5, are to be
subjected to a pressure of approximately 10,000 pounds per square inch
after assembling, before closing cap is screwed on and adjusted.


=Lacquering and Polishing.=--The exterior surfaces of the fuse are
to be polished and lacquered with a lacquer consisting of 1 pound of
seedlac, 8 ounces of turmeric, and 8 pounds (1 gallon) of methylated
spirits. The groove in the top and bottom composition rings, the
magazine recess in the body, the powder channels and groove in the
base plug, and the powder chambers of time detonator and percussion
detonator holder, are to be lacquered with a lacquer consisting of 10
grains of rosaniline, 1¹⁄₂ pound of powdered shellac, and 1 quart of
methylated spirits.


=Screw Threads.=--The screw threads must, unless otherwise stated on
the drawing, be of the British standard fine screw thread, and conform
to the standard gages of the government inspector. For fuses not made
in England, the British standard threads will not be insisted upon,
except for the large thread on the body.


=Time Arrangement.=--The grooves on the under side of the composition
rings are to be charged with 56 grains of No. 22 meal powder compressed
at 68,000 pounds per square inch; the rings are then to be faced off,
and the holes at the ends of the channels drilled. The onion skin
paper washers are to be secured to the surfaces by shellac. Perforated
pellets of black powder are to be inserted in the flash hole in the top
ring, escape hole and flash hole in bottom ring, and flash hole in the
body, the pellets for escape hole in bottom ring and flash hole having
the perforation filled with loose gun cotton. The space at the end of
the channel in the bottom ring is to be filled with loose meal powder.
An onion skin paper patch is to be secured over the flash hole in top
ring, and the escape hole in bottom ring closed by a brass disk secured
by two center-punch holes, and coated with shellac. The cloth washers
are to be secured on the upper faces of the body and the lower time
ring with fish glue, and subjected to a pressure of 10,000 pounds per
square inch.

[Illustration: Fig. 5. Details of British Combination Fuse]


=Assembling and Closing.=--The different parts of the fuse are to be
put together as in the assembly view, Fig. 1. The cap is to be screwed
down so that a turning moment of 325 ± 25 inch-ounces will just turn
the ring, the cap being secured by means of a set-screw. The bench or
table upon which the tensioning apparatus is fixed is to be jarred by
tapping with a mallet to assist the turning of the ring. The base plug
is to be screwed into the body, and the magazine filled with fine-grain
powder through the filling hole. The bottom of the fuse is to be coated
with shellac varnish.


=Delivery.=--The fuses are to be delivered in lots of 2000, an
additional 40 being supplied free, for purposes of proof. In the event
of further proof being required, the fuses will be taken from the lot.


=Proof.=--The fuses selected for proof will be tested as follows:

(a) Ten will have the percussion arrangement removed, and will be
tested to determine the mean time of burning at rest. The time train
will be set at the highest graduation mark. The mean time of burning,
set full when corrected for barometer, will be 22.9 seconds ± 0.4
second. The constant to be used, when correcting for barometer, is
0.023 of the mean time of burning, for every inch the barometer reads
above or below 30 inches, being plus when above and minus when below.
The difference between the shortest and longest time of burning is
not to be more than 0.5 second. If the lot fails to pass this test,
a further proof will be taken; the fuse must burn within the limits
specified above, otherwise the lot will be rejected. Should the
detonator fail to ignite the time ring, a second proof will be taken;
should a similar failure occur at second proof, or should there be more
than one such failure at first proof, the lot will be rejected.

(b) Twenty fuses will be fired, at the same elevation, in any of the
following guns, with full charges, and the time of burning noted. The
requirements as to the result of the firing with the fuses set at
different graduations are as given in detail in the following:

1. The mean difference from the mean time of burning of the 20 fuses is
not to exceed:

  In 18-pounder guns    if set full            0.14 second
                        if set 16              0.11 second

  In 13-pounder guns    if set full            0.2 second
                        if set 14              0.13 second

The difference between the longest and shortest fuse is not to exceed:

                        if set full            0.75 second
  In 18-pounder guns    or omitting one fuse   0.6 second
                        if set 16              0.6 second
                        or omitting one fuse   0.5 second

                        if set full            0.9 second
  In 13-pounder guns    or omitting one fuse   0.7 second
                        if set 14              0.7 second
                        or omitting one fuse   0.5 second

2. If there is one blind fuse, a second proof will be taken. If there
is a blind at second proof, or more than one such failure at first
proof, the lot will be rejected.

(c) Five fuses from a lot will be tested, in shrapnel shells, by firing
them set at “0” from a gun with a muzzle velocity of 1500 to 1800 feet
per second. The fuses should burst the shells at from 5 to 50 yards
from the muzzle of the gun. Should there be a burst in the gun, the lot
will be rejected. Should any fuse fail to act within 50 yards, second
proof will be taken; should a similar failure occur in the second
proof, or should there be more than one such failure at first proof,
the lot will be rejected.

(d) Five fuses from a lot will be tested in common shells by firing
them over sand, at such an elevation that the angle of descent will not
be more than 4 degrees. When one only of a set of fuses so fired fails
to burst on first graze the lot will be accepted without further proof;
if there be more than one failure to burst on graze in the second
proof, the lot will be rejected. The fuses must burst at the point of
impact. For percussion proof the time ring is to be set on the bridge.

(e) A premature explosion due to the fuse in any of the foregoing
proofs will cause the rejection of the lot.

(f) Should any other gun be introduced for proof of this fuse, which
differs from the above guns in either muzzle velocity or twist of
rifling at muzzle, the above conditions will be subject to modification.

(g) If, in the proof of any delivery, defects are found involving the
serviceability of fuses, additional proof may be taken from any other
delivery not finally closed, to ascertain if the defect is general.
Should the fuses fail at this further proof, the delivery will be
rejected without reference to the original proof. The total proof of
any delivery shall not exceed 5 per cent of the lot. The contractor
will be required to replace all fuses expended in further proof or
examination free of charge, which, whether fired or otherwise tested,
will become the property of the government.

[Illustration: Fig. 6. Details of British Combination Fuse Cover and
Case]


=Inspection.=--(a) The components of the fuses, during manufacture and
assembling, and the completed fuses after delivery, will be subject to
examination and gaging by, and to the final approval of, the chief
inspector or an officer deputed by him. Any component or fuse, which
is not finished to the satisfaction of the chief inspector, or his
representative, or which has any flaw or imperfection, will be rejected.

(b) If, at any time during examination, it is found that defects of any
nature which involve rejection of the defective components, or fuses,
amount to 5 per cent of the number in the lot, the lot will be rejected.

GRADUATION TABLE FOR TIME RING ON BRITISH COMBINATION TIME AND
PERCUSSION FUSE

[Illustration]

  +--------------+------------+
  |              |    Angle   |
  | Graduation   +------+-----+
  |              | Deg. | Min.|
  +--------------+------+-----+
  | 0 to 5       | 26   | 0   |
  | 0 to 1       | 16   | 45  |
  | 1 to 2       | 15   | 15  |
  | 2 to 3       | 15   | 30  |
  | 3 to 4       | 16   | 30  |
  | 4 to 5       | 14   | 40  |
  | 5 to 6       | 14   | 35  |
  | 6 to 7       | 14   | 15  |
  | 7 to 8       | 13   | 55  |
  | 8 to 11 each | 13   | 35  |
  | 11 to 12     | 13   | 20  |
  | 12 to 13     | 13   | 10  |
  | 13 to 14     | 13   | 0   |
  | 14 to 15     | 12   | 50  |
  | 15 to 16     | 12   | 30  |
  | 16 to 17     | 12   | 0   |
  | 17 to 18     | 11   | 30  |
  | 18 to 19     | 13   | 10  |
  | 19 to 20     | 14   | 30  |
  | 20 to 21     | 16   | 20  |
  | 21 to 21.2   | 3    | 30  |
  +--------------+------+-----+

(c) If, at any time during examination of the lot, it is found that 5
per cent of fuses in the lot depart from the approved design, further
examination will be suspended. The whole of the lot must be re-examined
by the contractor and those fuses which are incorrect to design
eliminated. Those fuses in which the departure can be rectified may be
changed to the approved design by the contractor. The lot may then be
re-submitted for examination.


=Tests for Safety in Transportation.=--From each lot, 20 time and 20
percussion plungers are to be tested to ascertain the correctness of
their weights and static resistances. Lots of plungers not correct
within the tolerence allowed will be rejected. At the commencement of
manufacture, 6 time and 6 percussion plungers from each lot will be
subjected to a drop test against a steel block 11.5 inches in diameter,
4.5 inches thick, resting on a concrete pier, to determine the limit in
heights at which the same will arm when carried in standard dropping
pieces. One of the pieces weighs 15 pounds and has the form of a 3-inch
shell; the two other pieces are lighter and smaller. No concussion
plunger is to begin to arm when falling in the lighter piece from a
height of 4 feet 6 inches; all shall fully arm in the shell with 14
feet 8 inches drop. No percussion plunger is to begin to arm in the
special piece falling with 6 feet 2 inches drop; all shall fully arm in
the shell with a 17 feet 6 inches drop.


=Jumbling and Jolting Test.=--Ten fuses will be placed, one at a time,
in a wooden box approximately 16 inches by 11 inches by 5 inches inside
dimensions, revolving at thirty revolutions per minute, about one of
its diagonals, for four hours. The fuses will then be placed in an
adjustable fuse-holder on the end of a hinged lever 16 inches long,
which, by the motion of a cam, is raised 4 inches, thirty-five times
per minute, and allowed to drop on an iron anvil. The fuses are thus
dropped for an hour, point downward, base downward, and side downward,
respectively. The primer shields must not be marked, and the time
trains, powder pellets, etc., must be intact.




CHAPTER XII

SPECIFICATIONS FOR BRITISH 18-POUNDER QUICK-FIRING CARTRIDGE CASE AND
PRIMER


The following specifications of the British 18-pounder quick-firing
cartridge case and primer govern the manufacture and inspection
of these cases and primers. They are abstracted from the official
specifications and give the most important information required by the
manufacturer and inspector.


=Construction.=--The cartridge may be either solid drawn brass or built
up, the nature of the alloy and the thickness and distribution of the
metal being left to the contractor, except that the dimensions must
agree with those in Fig. 1. The maximum weight is to be 3 pounds 1
ounce. If electrolytic copper is used, it must be melted and run into
ingots before use. In manufacture the number of drawings and the number
of annealings must not be less than six. Should any folds or rings
exist in the metal of the base, they must not be removed; any marks of
cutting or turning of the metal of the inside of the base will cause
the rejection of the cartridge. In the center of the base a hole is to
be bored and threaded to receive the primer. The cartridges are to be
marked on the base with the numeral and the contractor’s initials or
recognized trade-mark.


=Screw Threads.=--The screw threads must, unless otherwise stated,
be of the standard Whitworth thread, be cut full, and conform to the
government inspector’s standard gages. Contractors may send their gages
at any time to the chief inspector to be checked and compared with the
standard gages.


=General Conditions.=--The contractor is to supply, with the first
delivery, a full-sized tracing, on tracing cloth, of the cartridge he
is delivering. The contractor will also supply, free of charge, samples
of the metal from which the cases are to be made, if requested by the
chief inspector to do so. The samples should not be less than 6 by 2
inches. Cases in stock, that is, cases made before the date of the
contract, must not be submitted for acceptance under a given contract.

The cartridges should be delivered in lots of not less than 400. If
less than 400 are delivered, the number of rounds to be fired in
proof will be the same as if the delivery were the full 400. If, on
examination of twenty per cent of a lot, it is found that departures
from approved design, or defects of any nature, which involve rejection
of the cases, average twenty-five per cent of the number examined, the
whole of the lot will rejected.


=Proof.=--(a) Not less than one-half per cent will be fired in proof.
At least one cartridge from each 400 delivered will be fired three
times, one round being with a proof charge, and the cartridge being (if
necessary) reformed after each round. In each remaining cartridge, one
proof and one service round will be fired.

(b) The cartridge must load and extract easily, and must not split or
develop any flaw or crack on firing.

(c) The cartridge may be sectioned after firing; the section must show
no cracks.

(d) The maximum pressure is not to be more than 19 tons per square inch.

(e) If, in the proof of any delivery, defects appear which involve
the serviceability of the article, additional proof may be taken from
any other delivery not finally closed, to ascertain if the defect
is general or not. Should the cases fail at this further proof, the
delivery will be rejected without reference to the original proof.
The total proof of any delivery shall not exceed five per cent of the
number delivered.


=Replacement of Proof.=--The contractor will be required to replace
all cartridges expended in proof free of charge, and when the order is
approaching completion, he will be informed by the inspector how many
are required to complete the number on the order, exclusive of the
cartridges so expended, which, whether fired or otherwise tested, will
become the property of the government.


=Packing.=--All packages will be so marked that the goods contained
therein may be readily identified with the invoice. Unless specified
herein that the packing cases or other packing material will become
the property of the war department, they will remain the property of
the contractor, who is responsible for their removal. Should they not
be removed within two months of the acceptance of the cartridge cases,
they will be disposed of, and in such circumstances the contractor will
not be entitled to make any claim for compensation. The packing cases
must be marked “Returnable” or “Non-returnable.”

[Illustration: Fig. 1. British 18-pounder Quick-firing Cartridge Case,
giving Complete Dimensions, and Bore of Quick-firing Field Gun]


=Spontaneous Cracking.=--Any cartridge found to be cracked before or
after filling, but before firing, is to be replaced by the contractor
if such crack is discovered within six months of the date of acceptance
of the cartridge in question, which date is stamped on it.

The cartridges may be inspected during manufacture by, and after
delivery will be subjected to testing by, and to the final approval
of, the chief inspector, Royal Arsenal, Woolwich, England, or an
officer deputed by him.


=Primer.=--The primer is to consist of the following parts (see Fig.
2): body _A_; closing disk _B_; anvil _C_; plug _D_; cap _E_; tin foil
_F_; ball _G_; paper disk _H_; gun powder _I_; and Pettman cement. The
body is to be made of composition metal known as Class “A” or “B.” All
other metal parts of the primer, except where otherwise specified, are
to be made of brass. The brass is not to contain more than 0.3 per
cent of lead, nor to have more than one per cent of total metallic
impurities. The Class “A” or “B” metal is to be in accordance with
the following requirements: It must be perfectly straight, uniform
in diameter, and free from cracks or flaws, and must be capable of
standing the following minimum tests:

  +---------------------------------+----------------------------------+
  |     Tenacity, Tons per          |Elongation in Per Cent in such a  |
  |       Square Inch               |  Test Piece as can be furnished, |
  |                                 |  provided that                   |
  +---------------+-----------------+                                  |
  |    Yield      |   Breaking      |     Length / √Area = 4           |
  |    Point      |    Stress       |                                  |
  +---------------+-----------------+----------------------------------+
  | Class “A”, 20 |  Class “A”, 30  |      Class “A”, 20 per cent      |
  | Class “B”, 12 |  Class “B”, 20  |      Class “B”, 30 per cent      |
  +---------------+-----------------+----------------------------------+

Pieces of the metals it is proposed to use in the manufacture must be
submitted free of charge by the contractor, for testing, when requested
by the chief inspector.


=Body.=--The exterior of the body is to be turned and threaded and a
flange formed. Two slots are to be cut in the head for the key. The
interior is to be bored, cupped, and threaded. The exterior of the body
is to be lacquered with a lacquer consisting of:

  Seedlac              1 pound.
  Turmeric             8 ounces.
  Spirit, Methylated   8 pounds.


=Screw, Plugs and Copper Ball.=--A plug having one end turned to form
an anvil, which is to be free from burrs, is to be threaded to suit
the body. The interior is to be turned out to receive the soft copper
ball, and three fire holes bored. A plug is also to be threaded to suit
the body, having an annular recess turned on the inner side, and three
fire holes bored.

[Illustration: Fig. 2. Primer for British Quick-firing Shrapnel and
High-explosive Shell Cartridge Cases]


=Cap.=--The cap is to be made of copper and the interior is to be
varnished with varnish composed of:

  Finest orange shellac   2 pounds 2 ounces.
  Spirit, Methylated      8 pounds.

The specific gravity of the varnish is to be 0.885. It is then to be
charged with 1.2 grain of the following composition (figures give parts
by weight):

  Sulphide of antimony   18
  Chlorate of potash     12
  Ground glass            1
  Meal powder             1
  Sulphur                 1

The composition is to be pressed into the cap with a pressure of 800
pounds. A tin-foil disk, lacquered on one side, is then to be placed
on the composition with the lacquered side outwards, and placed under
a pressure of 400 pounds. It is then to be varnished with a varnish
composed of:

  Finest orange shellac   2 pounds 2 ounces.
  Seedlac                 1 pound.
  Turmeric                8 ounces.
  Spirit, Methylated     16 pounds.

The specific gravity of this varnish is to be 0.865.

The lacquer for the tin-foil disk before insertion is composed of:

  Seedlac              2 pounds.
  Turmeric             1 pound.
  Spirit, Methylated  16 pounds.

The specific gravity of this lacquer is 0.85.

The cap is to be externally coated with Pettman cement before inserting
in the body, and then a fillet of Pettman cement is formed between the
body and cap; Pettman cement is made from the following ingredients:

  Gum shellac          7 pounds 8 ounces.
  Spirit, Methylated   8 pounds.
  Tar, Stockholm       5 pounds.
  Red, Venetian       20 pounds 12 ounces


=Gun Powder.=--The primer is to be filled with R. F. G.^2 powder, the
screw plug being first screwed in and fixed by three small punch blows,
and the fire holes covered by a disk of paper secured with Pettman
cement.


=Closing Disk.=--A brass disk having a paper disk secured to it on the
inner side by Pettman cement is to be placed on the top of the powder,
and a ring of Pettman cement painted round the edge of the disk where
the metal will be burred over onto it. After the primer is burred over,
the whole of the exterior of the disk will also be coated with a thin
layer of the cement.


=Marking and Delivery.=--The primers will be marked with the numeral,
serial number, contractor’s initials or recognized trade-mark, and
date of manufacture. The primers will be delivered in lots of 1000,
an additional 20 being supplied for proof with each 1000, or any less
number supplied. In the event of further proof being required, the
primers will be taken from the lot.


=Proof.=--A percentage of the primers will be selected indiscriminately
for proof.

(a) The primer when screwed into a steel block must fire correctly with
a 1-pound weight falling 25 inches, and ignite a puff consisting of 4
drams of R. F. G.^2 powder enclosed in one thickness of shalloon, in a
12-inch vent with special receiver, or when proved in any gun for which
approved, it must ignite the charge without hang-fire.

(b) A miss-fire, hang-fire, pierced cap, or serious escape of gas
through or around the primer will cause rejection.

(c) The falling weight is to have a point of the same shape as the
service striker.

(d) Should the firing proof or examination of any delivery bring to
notice any defect or defects which, in the opinion of the chief
inspector, affect the serviceability of the primers, the delivery in
question may be rejected, or further proof taken at his discretion,
not only from the particular delivery, but from any others made by the
contractor which may be under inspection, to ascertain whether the
defect is general. Should any primers fail at these further proofs,
the delivery or deliveries will be rejected without reference to any
previous proof.

If, on examination of twenty per cent of a lot, it is found that
departures from approved design or defects of any nature which involve
rejection of the defective primers average 25 per cent of the number
examined, the whole of the lot will be rejected. The contractor will be
required to replace free of charge all primers expended in proof and
examination, which, whether fired or otherwise tested, will become the
property of the government.

[Illustration: Fig. 3. British Cartridge Clip]


=Specifications for Cartridge Clip.=--The general dimensions for the
cartridge clip are given in Fig. 3. The clip is made from hard-rolled
sheet brass in one piece. Four projecting arms are to be formed; the
ends of each are bent over as indicated. The clip is sand-blasted, and
lacquered with a lacquer composed of:

  Vegetable black                 1 pound.
  Seedlac                         1¹⁄₂ pound.
  Turpentine (1 quart)            2 pounds.
  Methylated spirits (6 quarts)  12 pounds.

One arm is coated with paint consisting of:

  Vermillion, dry                 2 ounces.
  Shellac, dry                    1 ounce.
  White hard varnish              ³⁄₄ ounce.
  Spirits, Methylated             1¹⁄₂ ounce.


=Loop.=--The loop is to consist of 13 inches of “webbing, cotton, ¹⁄₂
inch,” threaded through the clip and sewed. Three yards of webbing,
selected from the bulk, are to be submitted to the chief inspector
before being used. The webbing submitted will be cut into lengths of 11
inches and the ends of each length securely fixed in the clamps of a
testing machine, the clamps being 7 inches apart. The strain will be
gradually increased until the sample breaks. The breaking strain must
not be less than 200 pounds.


=Delivery.=--The clips will be delivered in lots of 1000. If, on
examination of 20 per cent of a lot, it is found that departures from
approved design, or defects of any nature, which involve rejection of
the clips average 25 per cent of the number examined, the whole of the
lot will be rejected.




CHAPTER XIII

SPECIFICATIONS FOR AMERICAN SHRAPNEL SHELLS


[Illustration: Fig. 1. Assembly and Details of American Shrapnel Shell]

The American shrapnel shells comprise the following parts: forged shell
body, copper driving band, head, washer, tubes, bullets, matrix, head
filler, diaphragm, base charge, and fuse. In some cases a Semple tracer
is used, and, when this is the case, the base of the shrapnel must be
machined to accommodate it.


=Shell.=--The shell is to be made of forged alloy steel or bar stock
having the properties outlined in Table I. The forgings must be
annealed so that they can be machined with reasonable ease. The maximum
elastic limit for the 2.95-inch and 3-inch shell forgings must not
exceed 115,000 pounds per square inch, and in case of the 3.8-inch,
4.7-inch, and 6-inch must not exceed 110,000 pounds per square inch.
All shrapnel shells must be subjected to an exterior hydraulic pressure
of 20,000 pounds per square inch up to the rotating band, and to an
interior hydraulic pressure of 1000 pounds per square inch. A certain
number from each 1000 shells are also subjected to a ballistic test by
firing completed shrapnels from a gun with a maximum pressure of 37,000
pounds, except for the 6-inch, which will be fired under a pressure of
22,500 pounds per square inch.

The shell is to be finished outside and inside except at points
otherwise indicated, where it is to be left in the rough-forged state.
The inside of the shell is to be coated with non-acid paint, except
where machined, and the powder chamber is to be given a heavy coat.
Great care should be taken to remove all burrs, scale, and sharp
corners. The outline of the shell after the first operation, when made
from bar stock, is shown by dotted lines in Fig. 1. The base of the
shell is to be machined as illustrated to the right at _A_ in Fig. 1,
when a Semple tracer is used.


=Copper Driving Band.=--The copper driving band is to be cut from
tubing of pure electrolytic copper, and machined to the dimensions
shown. It is to be heated and expanded to 2.985 inch inside
diameter--for the 3-inch shell--and is to be shrunk into the seat, then
forced into the scores by passing through a die and afterwards turned
to size.


=Washer and Head.=--The washer--for the 3-inch shell--is to be made
from steel 0.031 inch thick and formed to shape by punching. The head
is to be made from cold-drawn steel, finished all over, and coated
inside with a non-acid paint. The crimping wall is to be turned down
over the washer after machining, and a hole drilled after the head
is assembled to the shell. Five notches equally spaced are to be cut
around the head, and a crimping groove cut for putting on the fuse
protecting cap.

[Illustration: Fig. 2. Details of American Shrapnel Shell]


=Tube.=--The tube is to be made from seamless drawn brass tubing, and
is to be coated inside with shellac. An additional short tube is to
be inserted at the nose or mouth of this tube, next to the fuse; this
latter is to be made from seamless drawn copper, and is to be forced
into the tube under pressure and crimped over.


=Bullets.=--The bullets used in the shrapnel are to be made from 12.5
per cent antimony to 87.5 per cent lead, and are to be flattened with
six faces as shown in the illustration; 252 bullets are used in the
3-inch shrapnel.


=Matrix and Head Filler.=--The matrix is to consist of resin and
mono-nitronaphthalene, poured into the shell, as will be described in
connection with loading. The head is to be filled with melted resin,
poured in.


=Diaphragm.=--The diaphragm is to be made of forged steel to the
dimension shown. It is to be drilled and counterbored, and great care
should be taken to remove all burrs, sharp corners, and scale. The
bottom of the diaphragm is also to be given a heavy coat of non-acid
paint.

TABLE I. PHYSICAL PROPERTIES OF STEEL FOR VARIOUS SIZES OF SHRAPNEL
SHELLS

  +--------+-----------------+---------------+------------+------------+
  |Caliber,|Tensile Strength,|Elastic Limit, |Elongation  |Contraction,|
  |Inches  |Pounds           |Pounds         |in 2 inches,|Per Cent    |
  |        |Per Square Inch  |Per Square Inch|Per Cent    |            |
  +--------+-----------------+---------------+------------+------------+
  |  2.95  |     120,000     |     90,000    |     16     |    45      |
  |  3.0   |     120,000     |     90,000    |     16     |    45      |
  |  3.8   |     110,000     |     80,000    |     15     |    40      |
  |  4.7   |     110,000     |     80,000    |     15     |    40      |
  |  6.0   |     110,000     |     80,000    |     15     |    40      |
  +--------+-----------------+---------------+------------+------------+


=Fuse-hole Plug.=--There are two types of fuse-hole plugs; one is to
be made from die-cast white metal, of non-corrosive properties, and
machined to dimensions given in drawing, and the other of wrought
iron or bronze. The weight of the wrought-iron plug--for the 3-inch
shell--is to be 0.97 pound, and the weight of the bronze plug, 1.03
pound. Either type of fuse-hole plug may be used.


=Locking-Pin.=--Two steel locking-pins are required which must be
finished to limits of ± 0.005 inch, driven in and peened over after the
head is assembled in the shell.

TABLE II. PRINCIPAL DIMENSIONS OF AMERICAN SHRAPNEL SHELLS, HEADS AND
DIAPHRAGMS

[Illustration]

  +--------+----------+--------------------------+-------------+---------+
  |        | Shrapnel |      Shrapnel Shell      |Shrapnel Head|Diaphragm|
  |        | Forging  |                          |             |         |
  |Caliber,+-----+----+-----+---+-----+----+-----+----+---+----+----+----+
  |Inches  |  A  | B  |  C  | D |  E  |  F |  G  | H  | I | J  | K  | L  |
  +--------+-----+----+-----+---+-----+----+-----+----+---+----+----+----+
  |2.95    | 7.25|3.0 |0.30 |2.2|2.5  |2.95| 7.2 |2.85|1.7|1.05|2.5 |0.45|
  |3.0     | 8.66|3.05|0.375|2.1|2.375|3.0 | 8.5 |2.73|1.7|0.87|2.36|0.45|
  |3.8     |10.3 |3.85|0.50 |2.5|2.9  |3.8 |10.12|3.51|1.7|1.4 |2.89|0.55|
  |4.7     |13.2 |4.75|0.60 |3.0|3.5  |4.7 |13.00|4.25|1.7|2.3 |3.52|0.70|
  |6.0     |16.6 |6.05|0.80 |3.9|4.6  |6.0 |16.45|5.33|1.7|3.35|4.6 |0.80|
  +--------+-----+----+-----+---+-----+----+-----+----+---+----+----+----+


=Directions for Loading American 3-inch Shrapnel Shell.=--In loading,
make sure that the diaphragm seats firmly on the shoulder in the shell,
then pour in 0.25 ounce of powdered resin to seal the joints, and shake
down well to fill all cracks. The powdered resin becomes plastic when
the melted resin is poured in. Next put in one layer of bullets (18)
and pour in 0.4 ounce of melted resin; then put in 108 bullets and
pack by a pressure of six tons. Then pour in 3.75 ounces of melted
mono-nitronaphthalene; put in 126 bullets; drive down with mallet below
end of tube; and pour in 4 ounces of melted resin. After the mass has
thoroughly cooled, face off matrix so that the depth from the end of
the shell shall be 0.27 inch to allow for screwing in head, which
should bear down hard on matrix. Next place washer in head and secure
it by turning down crimping wall. Then fill annular space in lower
face of head with melted resin, and after this is thoroughly cooled,
face off flush with lower end of head. Screw head in place and secure
with pins; then insert inner tube, pour in the base charge through the
tube, and insert stopper. After the shell has been loaded, the shell
and head should be painted from the rotating bands to the rear edge of
the groove. For waterproofing, coat with a pure raw linseed oil black
paint. Coat the remainder of the head with bitumastic solution, and
crimp the waterproof cover in place while the solution is plastic.
In the lower end of the inner tube should be placed a stopper of dry
fibrous gun cotton rolled tightly into a cylinder and pressed down
until it rests on the shoulder of the diaphragm and is about one inch
long.

TABLE III. WEIGHTS AND MATERIALS USED IN AMERICAN 3-INCH SHRAPNEL SHELLS

  +---------------+-------------------------------+----------------+
  |     Part      |           Material            |Weight in Pounds|
  +---------------+-------------------------------+----------------+
  |     Shell     |             Steel             |     5.80       |
  |  Driving Band |             Copper            |     0.15       |
  |     Washer    |             Steel             |     0.02       |
  |      Head     |             Steel             |     0.45       |
  |Tube (including|       Brass and Copper        |     0.09       |
  |  inner tube)  |                               |                |
  | Bullets (252) |      Lead-antimony Alloy      |     6.05       |
  |     Matrix    |Resin and Mono-nitronaphthalene|     0.52       |
  |  Head Filler  |             Resin             |     0.03       |
  |   Diaphragm   |             Steel             |     0.47       |
  |  Base Charge  |        Shrapnel Powder        |     0.17       |
  |      Fuse     |                               |     1.25       |
  | Semple Tracer |                               |     0.20       |
  |Tracer Support |                               |     0.17       |
  |  Total Weight |                               | 15.37 ± 0.15   |
  +---------------+-------------------------------+----------------+

The case is to be stamped as follows with letters ¹⁄₁₆ inch high: Lot
number of shrapnel shell, purchase order, date of issue of purchase
order, fiscal year, and initials of manufacturer.


TABLE IV. PRINCIPAL DIMENSIONS OF VARIOUS SIZES OF CARTRIDGE CASES USED
ON AMERICAN SHRAPNEL SHELLS

[Illustration]

  +----------+-----------------------------------------+
  |          |           Dimensions in Inches          |
  | Caliber  +------+------+------+------+------+------+
  |in Inches |  A   |  B   |  C   |  D   |  E   |   F  |
  +----------+------+------+------+------+------+------+
  |   3.0    | 3.5  | 3.2  | 0.06 | 0.04 | 3.05 | 10.8 |
  |   3.8    | 4.3  | 4.05 | 0.07 | 0.04 | 3.75 | 14.4 |
  |   4.7    | 5.25 | 5.00 | 0.10 | 0.05 | 4.75 | 16.8 |
  |   6.0    | 6.75 | 6.50 | 0.08 | 0.04 | 6.25 | 10.0 |
  +----------+------+------+------+------+------+------+


=Cartridge Case.=--The various sizes of American cartridge cases for
shrapnel shells are drawn from a blank of brass, known as “cartridge
brass.” The principal dimensions of the various sizes of cases are
given in Table IV.

The specifications covering the time and percussion fuse used in
American shrapnel shells are the same as for the British “No. 85,”
given in Chapter XI, with the one exception that the base of the fuse
body is shaped to suit the American shell, and the thread is the U. S.
standard, instead of Whitworth standard.




INDEX


  American shrapnel shell, section of, 3
    specifications, 286

  American type of fuse, 8

  Annealing and washing cartridge cases, 178

  Automatic Machine Co.’s threading lathe used for threading shells, 129


  Band, machining rifling, 68
    pressing on rifling, 66

  Besly grinder equipped for grinding shrapnel, 137

  Brass for cartridge cases, 235

  Brass plugs for fuse, forging, 145

  Brass socket, machining, 146

  British cartridge cases, specifications, 276

  British fuses, specifications, 260

  British primers, specifications, 279

  British shrapnel shell, section of, 3
    specifications, 251

  Brown & Sharpe machines used for making fuse parts, 164

  Bullets, shrapnel, 140


  Caley method of making shrapnel forgings, 20

  Cartridge cases, annealing and washing, 178
    cupping, 176
    drawing, 172
    list of operations, 190
    machining, 180
    specifications for British, 276
    specifications for Russian, 231
    summary of operations, 192
    testing hardness of, 179

  Cartridge clip, British, 284

  Cleveland “Automatic” used for making shrapnel shells, 85

  Clip, British cartridge, 284

  Closing cap, machining, 162

  Closing screw, machining, 162

  Copper rifling band, machining, 68
    pressing on, 66

  Cupping cartridge cases, 176


  Detonators, 15
    specifications for Russian, 245

  Diaphragm forging, 39

  Drawing operations on cartridge cases, 172
    table of operations, 190

  Drilling percussion primers, 167

  Drilling timing fuse plugs, 170


  Explosives, classification of, 14
    in shrapnel shells, 4
    manufacture of high, 18


  Forging brass plugs for fuse, 145

  Forging diaphragms, 39

  Forging fuse sockets, 143

  Forging shrapnel heads, 38

  Forging shrapnel shells, 20

  French shrapnel shell, section of, 3

  French type of fuse, 11

  Fulminates, 15

  Fuse, American type, 8
    French type, 11
    Russian type, 9
    specifications for British, 260
    specifications for Russian, 213
    time and percussion, 6
    Vickers’ type, 228

  Fuse bodies, machining, 150

  Fuse hammers, making, 165

  Fuse nose, machining, 156

  Fuse nut, making, 166

  Fuse parts, making, 143

  Fuse plugs, drilling, 170

  Fuse sockets, forging, 143

  Fuse timing ring, graduating, 171


  Gages for shrapnel parts, 72, 73

  Gaging shrapnel shells, 71

  German shrapnel shell, section of, 3

  Graduating fuse timing ring, 171

  Gridley “Automatics,” used for making fuse parts, 156
    used for making shrapnel shells, 103

  Grinding shrapnel shells, 64, 132


  Hardness testing, of cartridge cases, 179
    of shrapnel shells, 48

  Head, machining shrapnel, 152

  Heading operations on cartridge cases, table, 190

  Heat-treating department, lay-out of, 58, 59

  Heat-treatment of shrapnel shells, 47

  Holinger method of making shrapnel forgings, 25

  Hydraulic press method of forging shrapnel, 29


  Libby turret lathe used for machining shrapnel shells, 122

  Lo-swing lathe used for machining shells, 114


  Machines for shrapnel manufacture, 75

  Machining shrapnel shells, 40

  Marking shrapnel shells, 74


  New Britain “Automatics” used for making fuse parts, 146

  Norton method of grinding shrapnel shells, 133


  Percussion primers, drilling, 167

  Potter & Johnston “Automatics” used for machining forged shells, 90

  Powder, black, 15
    smokeless, 16

  Powder cups, press tools for, 139

  Press tools for powder cup, 139

  Primers, charging, 246
    for fuses, drilling, 167
    specifications for British, 279


  Reed-Prentice equipment for machining shrapnel shells, 75

  Rifling band, machining, 68
    pressing on, 66

  Rough-turning operations on shrapnel forgings, 43

  Russian cartridge cases, specifications for, 231

  Russian combination fuse, Vickers’ type, 228

  Russian shrapnel shell fuses, specifications, 213

  Russian shrapnel shell, section of, 3
    specifications, 194

  Russian type of fuse, 9


  Shrapnel bullets, 140

  Shrapnel cartridge cases, 172

  Shrapnel head, forging, 38
    machining, 152

  Shrapnel shells, forging, 20
    grinding, 64, 132
    heat-treatment, 47
    history, 1
    machines and tools for manufacture, 75
    machining, 40
    present design, 2
    specifications for American, 286
    specifications for British, 251
    specifications for Russian, 194
    steel for, 51
    types, 3

  Smokeless powder, 16

  Socket, machining, 146, 150

  Specifications, for American shrapnel shells, 286
    for British cartridge cases, 276
    for British fuses, 260
    for British primers, 279
    for British shrapnel shells, 251
    for Russian cartridge cases, 231
    for Russian shrapnel shells, 194
    for Russian shrapnel shell fuses, 213

  Steel for shrapnel, 51


  Tensile strength, testing, 48

  Testing hardness of cartridge cases, 179

  Testing shell body for hardness and tensile strength, 48

  Threading shells, 129

  Timing fuse plugs, drilling, 170

  Timing ring, graduating, 171
    machining, 162

  Tools for shrapnel manufacture, 75


  Varnish for cartridge cases, 242

  Vickers’ type of fuse, 228


  Warner & Swasey turret lathe, used for machining bar-stock shells, 112
    used for machining forged shells, 109

Transcriber’s Notes.

Italic text is indicated with _underscores_, bold text with =equals=.
Small/mixed capitals have been replaced with ALL CAPITALS.

Evident typographical and punctuation errors have been corrected
silently. Inconsistent spelling/hyphenation has been normalised.

The word ‘gaged’ has been inserted at page 239; “3. All outside
dimensions of the bottom of the case are gaged as follows:”

A half-title page has been discarded.

Some illustrations and tables have been relocated to improve text flow.

New original cover art included with this eBook is granted to the
public domain.




*** END OF THE PROJECT GUTENBERG EBOOK 78213 ***