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uf

MANUFACTURE

OF

ARTILLERY AMMUNITION

McGraw-Hill BcK)kCoittpai5r

PujSC£s/iers ofSoo/^/br

ElGCtrical World TheEngjlneeriiig andMining Journal tngiiieGrii^ Record Engineering News

Railway A^ Gazette American Machinist

Signal EngiriQer American Engpieer

Electric Uailway Journal Coal Age

ME>talltu'gical and Chemical Engineering Power

MANUFAOTUEE

OF

AETILLERY AMMUNITION

BY MEMBERS OF THE EDITORIAL STAFF OF THE AMERICAN MACHINIST

L. P. ALFORD, Editor-in-Chibp f. h. colvin ^ e. a. suverkbop

Robert Mawson John H. Van Deventer

First Edition

McGRAW-HILL BOOK COMPANY, Inc

239 WEST 39TH STREET. NEW YORK

LONDON: HILL PUBLISHING CO., Ltd.

6 A 8 BOUVERIE ST., E. C. 1917

• •

Copyright, 1917, by the McGraw-Hill Book Company, Inc.

THK MAPX«B PRKBS "T O R K PA

FOREWORD

By Howard E. Cofpin

Member, Naval Consulting Board of the United States, and Chairman of its Committee on Industrial Preparedn^; Member, Advisory Com- mission of the Council of National Defence. Vice- President, Hudson Motor Car Co.

Our vital national need for a text-book dealing with the quantity manufacture of army and navy materials should require little either by way of explanation or comment. Two years of experience on orders for foreign governments have taught our American manufacturers that the making of materials of modem warfare is a new art. It is an art with which we have had little or no previous experience and in which our workmen are unskilled.

In England, a little over two years ago there were not more than three government arsenals. Today more than four thousand of Eng- land's leading industrial plants are being operated as government factories for the production of war materials, and many other thousands of factories still under private control are concentrating their energies in the same direction. The teaching of the munition-making art to these thousands of manufacturers and to millions of industrial workers, both men and women, has called for a work in industrial organization and education such as the world has never before seen. In France, in Germany, in Italy, in Japan, and even in Russia, this same education and organization of the industrial forces is going forward.

We have here in the United States vast resources in manufacturing and producing equipment, but they are unorganized and uneducated for the national service. Our observations of the European war have taught us that it is upon organized industry that we must base any and every plan of military defence, and that in the event of trouble with any one of the several first-class powers, between eighty and ninety per cent, of our industrial activity would, of necessity, be centered upon the making of supplies for the government. We have learned also that from one to two years of time and of conscientious effort are needed to permit any large manufacturing establishment to change over from its usual peace time commercial line to the quantity-production of war materials for which it has had no previous training. Delays of this kind, in time of

vi FOREWORD

emergency, cannot but result in closed plants, in the disruption of labor organizations built up over a period of years, in a loss of skilled men through enlistment for the fighting front, and in those same chaotic conditions which wrought near disasters to several of the nations at the outbreak of the European struggle.

We have had no experience in the kind of warfare now being waged abroad, and yet this is exactly the sort of thing for which we must pre- pare, or it is worse than useless that we prepare at all. Industrial pre- paredness is strictly in keeping with the natural tendencies and abilities of our people. It is the basic and at the same time the cheapest form of preparedness. We have already the investments in plants, in tools and in machinery, and more important still are our resources in skilled work- ers. But it is only through the most careful methods of organization and education that we may make all these resources available to us in time of emergency. Each manufacturing plant must be taught in time of peace to make that particular part or thing for which its equipment is best suited and for which, by a carefully prepared classification, it is to be held accountable in time of war. Annual educational orders, of such small sizes as not to interfere with commercial products, must be delivered each year under government inspection. There exists no other method of harnessing industry in the defensive service of this government. Every manufacturing institution in the country carries fire insurance; for the future it must demand war insurance as well.

An up-to-date text-book, dealing with munitions work, will be found indispensable in this educational campaign. We have heard much of the difficulties that American manufacturers have experienced in getting out foreign war orders. Months of experimentation, argument and delay have resulted because of the lack of proper information as to the tools, processes and methods involved in the quantity-production of such materials. Fortunately for us, we have not been one of the principals involved in the European struggle, and however costly failure in delivery may have been to individual manufacturers, it has not produced a national calamity.

The work of the Naval Consulting Board involves three steps: First, an inventory of the coim try's manufacturing and producing resources;*

* Under the Committee on Industrial Preparedness, many thousands of patriotic American engineers have devoted time and money in an inventory of the more than thirty thousand manufacturing institutions in this country doing a business in excess of one hundred thousand dollars per year.

The American Society of Civil Engineers, the American Institute of Mining Engineers, the American Society of Mechanical Engineers, the American Institute of Electrical Engineers, and the American Chemical Society, having a combined membership of more than thirty-five thousand, have co-operated in this work through state and territorial directorates of five men each. These directors, two hundred and fifty in all, have served at the request of the Secretary of the Navy as associate members of the Naval Consulting Board.

FOREWORD vii

second, the training and education of these resources for a national service both in peace and in war; ilmd,, the enlistment of the skilled laborer of the country in an industrial reserve which shall keep the trained worker in his place in the factory, the mill or the mine, and prevent his loss through enrollment in the fighting army. It is in the second step in this program, that the text-book of mimition manufacture will prove invalu- able. In the event of any future war in this coimtry, the mimition industry must become our one great national industry.

The work accomplished by the Committee on Industrial Preparedness of the Naval Consulting Board, has now been turned over to the newly created governmental body, known as the Coimcil of National Defence. It is imder the auspices of this Council that the education and organization of our resources for national emergency service will be carried forward. It is by this body that the text-book of munition-making will be put into the service of the nation.

Too much credit for this vitally important work cannot be given to Mr. L. P. Alford, Editor-in-Chief of the American Machinist, and to his corps of efficient workers who have cooperated so largely with the Committee on Industrial Preparedness. To him and to his staff is due the patriotic initiative, which has given to us in permanent form a record of the in- valuable experience gained by our manufacturers in the filling of foreign munition orders.

The personnel of the Committee on Industrial Preparedness, which created and directed this nation-wide patriotic activity, is as follows: Howard E. Coffin, Chairman; Wm. L. Saxtnbebs, Thomas Robins, Lawrence Addicks, W. L. Emmet, B. G. Lamme, Benjamin B. Thayer.

PREFACE

" Manufacture of Artillery Ammunition " has been written to preserve in permanent form a record of some of the great work done in United States and Canadian machine shops in producing munitions for the bel- ligerent nations of Europe. Much, though not all, of the information in its four sections has previously appeared in the American Machinist. All of the matter has been especially prepared for the book to make the treat- ment uniform and consistent.

Two major purposes have been before the authors in writing this i^cord of one of the sensational periods of the history of American machine «hop8. Never before have modem munitions of war been produced on this continent in large quantities. Never before have our machine shops 1>een called upon to turn out such an enormous volume of new products in fsuch ^ short time. A record should be preserved of this work to aid Americans in producing their own munitions of war if occasion should ever arise, and to show the excellent machining methods, machines, tools and appliances that have a much wider application in manufacturing than merely to make shells, cartridge cases and fuses. Such is the two- fold purpose that has brought this book into being — to aid in making munitions; to further machine^hop practice.

The material naturally divides into four sections: Shrapnel, high- exploeive shells, cartridge cases and fuses. In each, manufacturing methods are shown on a variety of sizes. The range for shrapnel is from 3 in. to 12 in.; for explosive shells from the 1-pounder to the 12 in.; for cartridge cases from the 1-poimder to the 4.5 in.; while the fuse section includes combination fuses, detonators and primers. Several appendices contain associate information, of which one part deals with machine tools and outlines some of the steps that might be taken for their control by the United States authorities in the emergency of war.

One of the important features of the book is the giving of production data, operation by operation, for each kind and size of ammunition whose manufacture is shown. It is believed that no other book has ever been written in any branch of the great machine-shop industry that gives such complete information on times and quantities of production.

The authors are glad to express their appreciation of the kindness of all the Canadian and United States manufacturers who opened their plants and made the collection of material possible. They also acknowl- edge their indebtedness to a few contributors to the American Machinist, whose articles have been incorporated in the book. And, finally, much

ix

X PREFACE

credit for whatever excellence of presentation the book may possess is due to Mr. Reginald Trautschold. It was his industry that shaped the pre- viously published material, collected additional information, and fitted

all together into a consistent whole.

The Authors.

New Yobk City. January J 1917.

CONTENTS

Page FORBWORD V

Preface ix

SECTION I Shrapnel

Chaptbb

I. What a Shrapnel Is and Does — The French 75-mm. Shrapnel ..... 3

II. Forging the Blanks for 18-Lb. British Shrapnel — Forging 3.3 Shrapnel

Blanks on Steam Hammers and Bulldozers 8

III. Making the 18-Lb. British Shrapnel— The Double-Spindle Flat Turret and the 18-Lb. British Shrapnel 31

IV. The Powder Cups for 18-Lb. British Shrapnel — ^Punching Steel Disks for British Shrapnel Shells — The Manufacture of 18-Lb. Shrapnel Shell Sockets and Plugs — From Birch Log to Fuse Plug 66

V. Three Inch Russian Shrapnel — Making 3-In. Russian Shrapnel in a

Pump Shop 83

VI. Manufacturing 12-In. Russian Shrapnel 146

VII. Making Shells with Regular Shop Equipment — Manufacturing Shrapnel Parts on Automatic Machines — ^Automatic Production of Shrapnel Parts — A Bridge Shop Transformed into an Arsenal 183

SECTION II

High-Explosive Shells

L What a High-Explosive Shell Is and Does — Explosives Used with High- Explosive Shells— Steel for High-Explosive Shells 231

II. Casting Steel Forging Blanks for 4.5-In. Explosive Shells — Forging the Blanks for 4.5-In. High-Explosive Shells — Forging Base-Plates for High- Exploaive Shells 236

III. Manufacturing British 18-Pounder High-Explosive Shells 251

IV. Manufacturing British 4.5-In. High-Explosive SheUs 312

V. Manufacturing British 8-In. High-Explosive Shells 366

VI. Operations on the British 0.2-In. Mark IX Howitzer Shell 389

VII. Operations on the British 12-In. Mark IV Howitzer Shell 399

VIII. Manufacturing the Russian 1-Lb. High-Explosive Shell 412

IX. Manufacturing Russian 3-In. High-Explosive Shells 442

X. Manufacturing 120-Millimeter Serbian Shells 460

XI. Manufacturing French 120-Millimeter Explosive Shells 494

SECTION III

Cartridge Cases

I. Manufacture of Cartridge Brass — Rolling Cartridge Brass 517

II. Making 1-Lb. Cartridge Cases 536

xi

xii CONTENTS

Chapteb Page

III. Making the 18-Lb. Cartridge Case — Drawing 18-Lb. Cartridge Cases on Bulldozers and Frog Planers — Cartridge Heading Presses and Accumula- tors at the Angus Shops 555

IV. Making the 4.5-In. Howitzer Cartridge Case 595

SECTION IV

Fuses and Primers

I. The Detonator Fuse — Making the British Detonator Mark-100 — Making

Adapters for British Detonator Fuse 623

II. Making the British Time Fuse Mark 80-i4 — Caps and Base Plugs for

Time Fuse — Making the Small Parts of the British Time Fuse .... 660 III. Making Primers for Cartridge Cases — Loading the Primers 705

APPENDIX

Machine Tools for Munition Manufacture — Composition and Properties of Shell Steel — flight Shells — Details of Some Shrapnels — Details of Some High-Explosive Shells — British Requirements for Projectile Inspection — British Prices for Hand Painting Shells — Diameter of British SheUs Oyer Paint — Weights and Dimensions of Some British Shells — Temperatures and Duration of Heat Treatment for British Shells 729

Index 761

C

SECTION I

SHRAPNEL

By JOHN H. VAN DEVENTER

Pagi

CHAPTER I. What a Shrapnel Is and Dobs 3

CHAPTER II. Forging Shrapnel Blanks 8

CHAPTER III. Making the Ig-Ls. British Shrapnel 31

CHAPTER IV. Powder Cups, Disks, Sockets and Plugs poh 18-Lb. British

Shrapnel 66

CHAPTER V. Making 3-In. Russian Shrapnel 83

CHAPTER VI. Manufacturing 12-In. Russian Shrapnel 146

CHAPTER Vll. Making Shells with Regular Shop EgmpMENT 183

MANUFACTURE OF ARTILLERY AMMUNITION

CHAPTER 1

WHAT A SHRAPNEL IS AND DOES'— THE FRENCH 76-MM.

SHRAPNEL

Shrapnel; because its explosion may be timed to a nicety, its rain of shot scattered at just the right instant, has proved one of the most effective tools of destruction in modern trench storming and defence. The shells of the various nations vary somewhat in shape and propor- tions, but their general construction is quite similar.

Fig. 1 shows a shrapnel shell casing such as has been extensively used in the great European war. These shells are manufactured in sizes from 2 to 15 inches in diameter.

The brass shell A that envelops the outside of the shrapnel casing is filled with powder, which is carefully measured to have the exact amount in each shell. This powder is ignited similarly to a cartridge in a gun and is intended to discharge the shell from the gun.

At fi is a powder pocket which contains the necessary amount of powder to explode the casing and scatter the charge.

A copper band, which is shrunk and also hydraulically pressed over the body of the shell, is shown at C. The outside diameter is turned somewhat larger than the gun bore, which is rifled or grooved in a spiral through its entire length.

When the shell is placed in the gun, the breech end admits it freely, but the gun bore being somewhat smaller and the copper being soft material, it is compressed and a portion of the copper ring sinks into these spiral grooves. Thus, when a shell is fired it has a rotary motion corresponding to the spiral of the gun, which means that the shrapnel is revolving at the same time it is traveling longitudinally. The rotary motion is so rapid that it keeps the shrapnel in practically a straight line laterally in its flight. If the gun did not have spiral grooves, when the shrapnel started to travel it would swerve against the resistance of the air, which would make it impossible to determine in what position it would explode. In other words, a smooth-bored gun and a smooth- surface shrapnel could not be depended upon for accuracy, and no scien- tific calculations could be made whereby shrapnel fired one after another would land in about the same place.

* J. P. Brophy, Vice-President and General Manager, Cleveland Automatic Machine Co.

3

4 SHRAPNEL ISbc. I

From this explanation it will be understood that the piece C is an important part of the shrapnel.

Details of De^gn. — A steel washer, which is pressed in position, is shown at D separating the powder pocket from the chamber of the shrapnel proper. This is commonly called "the diaphragm."

A copper tube connecting the

powder pocket B with the fuse body

H is shown at F. This contains an

igniting charge of gun cotton E at

a either end,

§ The shell casing is shown at G,

a the fuse body at H and a powder 10 passage /is shown at an angle con- s necting with the gun cotton. g The threaded connection between

.< fuse and shrapnel bodies at / is of ^ fine pitch, so that when the powder z is ignited at B the threads strip, P allowing the balls to be dischai^ed. H After the powder is ignited, if the I pressure is not great enough to de- g stroy the thread, the shell casing will burst at the end, which is its weakest point, and open up in b umbrella shape, the balls and body of the shell being driven with great force in all directions similar to the explosion of a skyrocket. This is very destructive within a radius of 60 ft. from where the explosion occurs. The Timing Device.^The time ring, graduated on its periphery, is shown at K. This controls the time of igniting the fuse J. When the time ring is set to zero the shell ex- plodes just after it leaves the muz- zle. The graduations indicate the explosion time at practically any number of feet desired up to the full range of the gun. On the inside of the graduated ring K a small opening is milled for ahout three-

Chap. U WHAT A SHRAPNEL IS AND DOES 5

fourths of a circle, so that the fuse cannot burn all way around. In this small opening the time fuse is placed, and at the bottom of the ring are small holes.

A loose piece N moves freely and carries at 0 an ignitible and highly explosive substance, which is so sensitive that if one drop were struck with a lead pencil held in the hand, it would shatter the end of the pencil before it could be withdrawn.

When the gun is in position, the range finder immediately estimates the distance to the enemy, and this information is given the gunners. The ring K is moved to the position which indicates the number of yards the shrapnel will travel after leaving the gun before it explodes. This is all taken care of in a few moments. The fuse on the inside of ring X, when ignited, burns in the direction that leads to the powder passage J, and the time taken to reach this determines the distance that the shrapnel will travel before exploding.

When the powder at J commences to burn, it ignites the gun cotton at E, and the flame passes through the tube F to the gun cotton at the opposite end, igniting the powder at B. The time taken by the flame to travel from J to B is diflicult to estimate because of its rapidity, but may be compared to the speed of electric current.

How the Fuse is Ignited. — ^A piece called a "free-moving slug" is shown at P. The moment the gun is fired, the shrapnel travels with such great rapidity that it causes this moving slug to rebound and come in contact with 0. The ignitible substance at 0 creates a flash, which burns back and around the chamber to the powder L, which leads to the fuse embedded in the face of the graduated ring K. The time, reckoned in fractions of seconds, that it takes to burn the fuse in the ring K before it reaches the powder J is calculated according to the distance the shell travels in flight before the charge is to be ignited at B,

If the shrapnel fails to explode at the correct distance because of the slug P not responding, then at the moment it comes in contact with anything in its path the sudden impact will carry forward the loose piece N, which is free to oscillate. This will mean a contact of the igniti- ble substance at 0 with the piece P. Ignition immediately takes place, and as piece N is in the forward position, the flame will travel in the direction of M. This action reverses the direction of the flash, as already explained. This means du-ect ignition through the powder passage M to the powder pocket B at lightning speed. The con- sequence is an instantaneous explosion of the shell at the moment it comes in contact with any object in its path, and extreme destruction at this point.

Refinements of Destruction. — The outside shape of the fuse body 0 is such as to ofifer the least resistance; in other words, it breaks up the air as it bores its way through. If this nose were longer or shorter.

6 SHRAPNEL [Sec. I

or a different shape, it would offer greater resistance, which would lessen both its speed and its range.

The muzzle velocity of the 3-in. shrapnel shell, which is being used so

extensively abroad, varies from

1,500 to 1,900 ft. per sec. dimng

the first second of flight, and

because of the air resistance,

diminishes in speed gradually

through the remaining distance

'' that it travels. The maximum

effective range is about 6,000

yd., and as the time fuse can be

set to explode at 100 yd, or less,

and at any point up to 6,000

yd., the time it would take to

J travel 100 yd. would be about

^ one-sixth second.

^ The balls are placed in the

I position shown and a special

3j wax is molted and poured around

^ them so that they are practically

^ a solid mass. The destruction

g which takes place when these

B balls, traveling at great velocity,

spread in the midst of hundreds

^ of human beings can easily be

I imagined.

The French 76-mm. Shrap- nel.— The shrapnel used in the celebrated 75-mm. French field guns differs in certain details from the shrapnel used by the British and American armies. No powder cap is used (see Fig. 2) and a nose containing balls is fitted in place of the timer. The fuse is screwed into this nose, the thread to receive it being shown in the illustra- tion. A feature of this loaded nose is the wooden holder that carries the lead balls. These are composed of 90 parta lead and 10 parts antimony.

The space for the powder charge in the base of the shell is varnished on

Chap. I] WHAT A SHRAPNEL IS AND DOES 7

all surfaces with a varnish composed of 200 grains of gum arabic cut in one liter of alcohol. This coating is also applied to the lower surfaces of the lower steel diaphragm. This diaphragm is seated in a packing of rubber to make a sealed joint.

Another point of difference between the British and French construc- tion is the method of keying the copper band. The British design calls for cutting a series of waves or drunken threads, around which the dead soft copper band is swaged. The French construction merely cuts a series of V-grooves into which the band is compressed.

CHAPTER II

FORGING THE BLANKS FOR 18-LB. BRITISH SHRAPNELS- FORGING 3.3 SHRAPNEL BLANKS ON STEAM HAMMERS AND BULLDOZERS'

The Montreal Locomotive Co., Montreal, Canada, when confronteb with the task of forging shell blanks for 18-lb. British shrapnel put every piece of equipment to work and in a remarkably short time were able to turn out an average of 3,000 completed blanks every 24 hr. These blanks were forged from 0.50 carbon steel and the allowable error on surfaces not subsequently machined was only 0.01 in. The bar stock steel blocks were heated and in only two operations squirted and drawn into shrapnel blanks. This record was maintained for months, not- withstanding the rigid inspection and tests demanded by the British Government, and a detailed description of the processes in vogue in the shops of the Montreal Locomotive Co. is one of a standard of efficiency in manufacture.

The steel for the forgings come in commercial bars, 10 to 12 ft. in length, the specifications for which call for 0.45 to 0.55 carbon, 0.70 man- ganese and less than 0.04 sulphur and phosphorus. These bars are stamped by the steel mill to indicate the "melt" from which they were made and test pieces from each "melt" are analyzed and broken by the Canadian Inspection Co. Three bars are then selected from each " melt " by the Montreal Locomotive Co.'s chemist and two pieces cut from each bar, one of which is again analyzed and the other made into a "test" shell and given the heat treatment. The "test" shells are then care- fully tested for tensile strength, etc., and if satisfactory in all respects the rest of the bars from the "melt" are cut to the standard length for shell-forging blanks, the blanks from each "melt" being kept together throughout manufacture.

Cutting the Bars. — Four methods of cutting the commercial bars into standard 4%-in. lengths for the shell blanks were employed, which are of interest as examples of rapid and accurate production. Fig. 3 shows a large Gorton cold-saw cutting four blanks at a pass. The bars A are held between the soft-wood clamps B, which are shaped to bring the bars to the same circle as the saw, thus reducing the travel and time of cutting to a minimum. Hardwood was tried at first, but did not grip the bars securely. On this machine 250 blanks can be cut in 10 hr.

* E. A. Suverkrop, Associate Editor, American Machinist.

8

Chap. 11) FORGING THE BLANKS EX>R SHRAPNEL 9

The clamps to the extreme right are not loosened until the bars are too short to handle in the saw, thus avoiding a lot of unneecBsary adjusting of the individual bars.

r A ooBTON <

In Fig. 4 is shown a Newton saw on the same work. This eaw has a capacity of 190 blanks in 10 hr. The stop A was at first secured to a

10 SHRAPNEL (Sec. 1

bracket attached to C. When thus attached, ita position with regard to the work was stationary and trouble was encount«red with the nearly severed blank jamming between the stop and the saw and breaking out the teeth. With the bracket B secured as shown to the eaw housing, the stop A is in contact with the end of the bar only when the saw is out of contact with the work. During the cut it is entirely out of contact, and at completion of the cut the blank is free to drop clear of saw and stop.

In Fig. 5 is shown a turret lathe used for cutting blanks. On the machine shown 256 blanks can be cut in 10 hr.

Fia. 5. CUTTINQ BLANKS ON TURRET

In Fig. 6 is shown the cutting of blanks on a large planer. The bars are held down by ordinary strap clamps and spacers are placed between them. Special holding devices for tools and work are in course of con- struction, whereby the output by this method will be from 400 to 600 blanks per day. Two tools are used in each head. The outer tools on each side are about ^ in. in advance of the inner tools so as to leave enough mel^l to resist the bending stresses. With all these methods ordinary cutting compound is used as a lubricant.

Removing the Burr, — A burr is left on all blanks except those which are cut while the bar rotates. This must be removed. The removal is a simple job with a pneumatic chisel, but the method of holding the work is worth showing. The machine steel block A, Fig. 7, secured to the bench is about S}4 in. high, 6 in. wide and 20 in. long, and weighs about 100 lb. The blank B is gripped by a J-s-in. sctscrew operated by a long crank handle C. The inertia of this heavy block steadies the work

FORGING THE BLANKS FOR SHRAPNEL

and makes cutting an easy matter. The crank handle is quickly operated. One operator can easily remove the burrs from all the blanks,

Forgiiig. — Forging was undertaken on a large flanging press, on a

a Inches)

{1} DimeneionB "A." "B" and "C" are the finiahcd internal sizes of shell. (2) At "D" this dimension allows material for machining equal to 0.05 in. per side. (3) The material on inside wall allowed tor machining from "C" to "D ' tapers from 0.0 to 0.05 in. per side. (4) At the shoulder "E" on which disk rests material 0.1 in. is allowed tor machining. (6) At "F" material is allowed for machining equal to 0.05 in. per side. (6) At "G" material is allowed for machining equal to 0.05 in. Care must betaken to remove all scale troro this part. {7) Face "H" to be machined by foiling manufacturers. (8) Projection "J to be left as shown on base unless Otherwise specified when forging are ordered. (9J Face "K" to be machined by forging manufacturers to dimensions given. (10) Dimension "L" allows for machin- ing, but this should not exceed 3.55 or 3.50 in. (11) Inside tinish of toroings from mouth of shell at face "K" to dimension "C" to be smooth and free from scale, projections, irregularities and other blemishes. The body must also be straight,

bulldozer and on drop presses and it is of interest to note that the dimen- sions and limits shown on Fig. 8 were maintained by workmen who had previously forged only locomotive frames and had never before been called

Chap. Ill

FORGING THE BLANKS FOR SHRAPNEL

13

upoD to work to huDdredths of an inch. The metal was worked hot which further complicated matters by necessitating allowances for shrinkage, and finally both the shop and the Government inspectors rejected any work which did not rigidly meet specifications.

First Forging Operation. — The cut-off blanks are charged into ordinary reverberatory furnaces, of which, there are two for each press. The furnaces are fired with oil at 25-lb. pressure and air at 7 oz. Each press is equipped with two sets of punches and dies, as shown in Fig. 9. The punches are made of 0.70 carbon steel, finished ail over and hardened but

4ThirBds I 1 ^ I ! *■

Punch ond Dte for Pisrcm^ Operation I. 9. PUNCHES AND DIES POH P1H8T POKGINQ OPERATION HAWKERS

not drawn. The dies are made of 0.70 carbon steel or chilled iron. It has been found that new punches and dies have a tendency to stick to the work unless they are first heated.

The work of adapting the lai^e flanging press and bulldozer to shell forging was taken care of by Robert Allison, works engineer, and while these two machines are now employed for th? second operation, a descrip- tion of the fixtures applied to them will not be out of place. In Fig. 10 is shown the fixture for the flanging press. With the exception of the punches and dies, which are for the second, or drawing, operation on the shell blanks, the fixture is the same as used for the first operation.

The flanging press is 155 tons capacity with a stroke of 30 in. It was found that to assure proper stripping a pull-back of 25 tons per forging is necessary. For that reason the pull-back on the press was increased to 55 tons.

Equipment for Flanging Press. — The flange G is bolted to the upper platen. The distance-piece D connects with the original ram to bring

the toola to handy working height. The two punches B are secured in . the head as shown. A swinging stop operated by the handle C is dis-

PIO. 10. EQUIPMENT SHOWN FOB SECOND

posed on each side of the press. In the plan view to the right the stop E is shown swung out of the way, while to the left it is in operating posi-

FORGING THE BLANKS FOR SHRAPNEL

tion. The swinging stop is used only when the second operation is in progress. At F are the guides for the punch head; at H are the seats for

the dies for both first and second operations; at / is a cored opening for the removal of the work on completion of the second operation.

16 SHRAPNEL [Sec. I

When the blanks have attained the proper temperature, a press feeder at each furnace removes one with a pair of tongs and, swinging it over ms head, brings it down end-on against an iron block to jar off as much of the scale as possible. Two men with the scrapers A, Fig. 11, and brooms then rapidly remove the rest of the scale and the feeders place the blanks in the dies. They then drop their tongs and take the guide B, Fig. 11, and lay it on top of the hot blank. The 3^^-in. recess is downward, surrounding the hot blank and centering it. The punch then descends, enters the 3}42-^^' opening on top, centers the guide and work with relation to itself and, passing on down, causes the hot metal to squirt upward around the punch. The press is then reversed and the punch ascends, bringing with it the forging, which is now about 7}^ in. long. Occasionally a forging will seize; then the punch is unscrewed and a new one inserted, which takes but a few minutes. When things are running right, the press will turn out 1,000 first-operation cups in 10 hr. At C in Fig. 11 is shown the blowpipe for removing scale from the dies in the first operation and at D the one for removing scale from the dies in the second operation. At E is shown the spray for cooling the punches in the second operation when they get too hot. The length of service of a punch or die depends upon many variables; it is, however, not uncommon for a die to last 24 hr.

As the requirements for the insides of the shells are more exacting, there being no machining inside except at the bottom, the punches under normal conditions require to be replaced more often than the dies, averaging 4 to 5 per day.

The gage //, Fig. 11, is used in inspecting the finished forging. The short leg goes on the inside of the shell, the difference between the length of the legs indicating the proper base thickness.

Special Fixtures for First Forging Operation. — Special fixtures designed by Mr. Allison to secure accuracy and high production on a special R. D. Wood & Co. press are illustrated in Fig. 12, the operation of which is as follows:

The plates B (in connection with the guide and stripping tool 5, Fig. 11) strip the work from the punches A, The dies. Fig. 9, are seated at C. The knock-out D is operated by the frame E hung from the ram by chains in the eye-bolts, which it will be noted hang at a slight angle. The knock-out D is simply a rivet which is actuated by the frame E. In the position shown, the bottom of the knock-out D enters a hole in the frame member E and the top of D comes flush with the bottom of the die. As the punch A descends, frame E also descends and on clearing the end of the knock-out D swings by gravity to such position that when the punch and frame again ascend, the bottom of D is struck and the work ejected from the die C. After the removal of the work, the operator pushes frame E in the direction of the arrow until the stop H strikes the

Chap. II]

FORGING THE BLANKS FOR SHRAPNEL

17

frame of the press, when the knock-out D again drops into the pocket of frame E and the die C is ready to receive another blank.

In construction, the two stops / are simple and efficient, but under the repeated poundings, the punches and the stops are gradually upset so that adjustments must be made from time to time. Adjustment is

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FIG. 12. SHELL-PIERCINO DETALS

secured in the following simple manner: On top of each post-stop / is an inverted cup J supported by thin sheet-steel shimes, one or more of which can be removed or inserted to readjust the length of stroke.

Second Forging Operation. — A bulldozer is chiefly employed for the second-operation work. This machine, see Fig. 13, has accommodation for the three punches and dies shown in Fig. 14.

2

18

SHRAPNEL

[Sec. I

The work goes through one die at a time, passing in succession through the three dies mounted in the consecutive seats B in the fixture A, Fig. 13. The bottom of the shell is formed at the end of the stroke between the punch end and a bottoming die located at C, It will be noted that

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the punches have a head instead of a thread to hold them in. A %-in. setscrew D on top prevents the dies falling out. The cups from the first operation being hot, the operator takes them one at a time and holds them with the base toward the die. The bulldozer is tripped and the

Chap. II]

FORGING THE BLANKS FOR SHRAPNEL

19

advancing punch enters the hole in the work, pushing it through the die and against the bottoming die C. By this time the operator standing on top of the fixture A has had time to replace his tongs with a hand stripper which is merely a crotch of steel with a long handle, shown at E, Fig. 13. The crotch is placed over the punch between the work and the front flange F of the fixture, and on the return of