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diff --git a/78213-0.txt b/78213-0.txt new file mode 100644 index 0000000..13a3f6a --- /dev/null +++ b/78213-0.txt @@ -0,0 +1,8293 @@ +*** 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 *** |