HIGH-EXPLOSIVE SHELL
MANUFACTURE
HIGH-EXPLOSIVE SHELL
MANUFACTURE
A COMPREHENSIVE TREATISE ON THE FORGING,
MACHINING AND HEAT-TREATMENT OF HIGH-EX-
, PLOSIVE SHELLS AND THE MANUFACTURE OF
CARTRIDGE CASES, PRIMERS, AND FUSES, GIVING
COMPLETE DIRECTIONS FOR TOOL EQUIPMENT
AND METHODS OF SETTING UP MACHINES,
TOGETHER WITH A REVIEW OF THE MAKING OF
POWDERS, HIGH EXPLOSIVES, AND FULMINATES
By DOUGLAS T. HAMILTON
ASSOCIATE EDITOR OF MACHINERY
AUTHOR OF "ADVANCED GRINDING PRACTICE,"
"AUTOMATIC SCREW MACHINE PRACTICE,"
"SHRAPNEL SHELL MANUFACTURE,"
"CARTRIDGE MANUFACTURE," ETC.
FIRST EDITION
NEW YORK
THE INDUSTRIAL PRESS
LONDON: THE MACHINERY PUBLISHING CO., LTD.
1916
COPYRIGHT, 1916
BY
THE INDUSTRIAL PRESS
NEW YORK
PREFACE
The manufacture of high-explosive shells has, within the
past year, become one of the most important of the
mechanical industries in this country, and the design of
these shells and the machining of their component parts are
now of the greatest interest to a large number of manufac-
turers, designers, toolmakers, and mechanics in general.
Machine tool builders have been called upon to provide tools
and devices of standard and special design to meet the
demand for rapid and accurate production. As a result,
there has been a remarkable development in the tool equip-
ment, and in the methods used in the forging and machin-
ing of shells. The larger sizes of high-explosive shells are
made mainly from forgings, while the smaller sizes are
made from bar stock. The forged shell blanks are made by
means of hydraulic forging presses, bulldozers or special
forging machines that have been developed primarily for
this class of work. When made from bar stock, high-
powered drilling machines or similar machines of special
construction are used. Great developments have taken place
in regard to the machines suitable for high-power drilling.
This book, which is a companion volume of the treatise
already published on "Shrapnel Manufacture," has been
brought out to meet the demand for a comprehensive book
dealing with the construction, forging, machining, heat-
treatment, inspection, and testing of high-explosive shells.
It covers completely the methods of machining these shells
when made either from bar stock or from forged blanks. In
addition, the manufacture of high-explosive or detonating
fuses, cartridge cases, primers, etc., is dealt with in detail.
In the book is included all the material on the subject pub-
lished during the past year in MACHINERY, supplemented by
other material wherever necessary to complete the treatise.
The different classes of powder, high-explosives, and
fulminates have also been described, and a brief outline is
338017
given of their manufacture. An endeavor has also been
made to indicate the difficulties that manufacturers have
met with in the making of high-explosive shells. Due to the
fact that the information given is very complete and covers
all the different phases of the work, it is believed that the
book will prove a valuable companion volume to those
already brought out by the Publishers of MACHINERY on the
manufacture of munitions.
D. T. H.
New York, January, 1916.
CONTENTS
PAGES
CHAPTER I.
High-explosive and Armor-piercing
Shells : 1-31
CHAPTER II.
Explosives, Detonators and Fulminates . 32-41
CHAPTER III.
Forging High-explosive Shells 42-52
CHAPTER IV.
Machining British 18-pound Shells 53-79
CHAPTER V.
Machining Russian and Serbian Shells. 80-99
CHAPTER VI.
Machining French 120-millimeter (4.72-
inch) Shells 100-126
CHAPTER VII.
Machining British Howitzer Shells 127-144
CHAPTER VIII.
Miscellaneous Tools and Devices for
Shell Manufacture 145-162
CHAPTER IX.
British High-explosive Detonating Fuse 163-180
CHAPTER X.
High-explosive Cartridge Case Manu-
facture 181-211
CHAPTER XL
Making Cases with Bulldozers and
Planers 212-224
CHAPTER XII.
Cost of Munitions of War. . 225-227
HIGH-EXPLOSIVE SHELL
MANUFACTURE
CHAPTER I
HIGH-EXPLOSIVE AND ARMOR-PIERCING SHELLS
THE common high-explosive shell which is used chiefly
for the destruction of fortifications did not come into gen-
eral use until the latter part of the sixteenth century.
About that time, hollow balls of cast iron were filled partly
with black gunpowder and partly with a slow-burning com-
position that was ignited by several different types of fuses.
These shells did not give very satisfactory results. An im-
provement was made by fitting into the shell a hollow forged
iron or copper plug filled with slow-burning powder. Until
about 1871, the shells were spherical in shape and were fired
from smooth-bored guns (not rifled).
Development of High-explosive Shells. Upon the ad-
vent of the rifled gun, sabots, as shown in Fig. 1, were fas-
tened to the base of the spherical shell and took the rifling
grooves in the gun. These were usually made of wood and
the rim was covered with sheet iron, steel, or copper. When
the first types of high-explosive shells burst, they broke into
comparatively large pieces, and did not have a very destruc-
tive effect. Later developments consisted in making the
shells from cast or forged steel and filling them with high-
explosives such as lyddite, melenite, shimose, etc., instead
of common black gunpowder. These shells were sometimes
cast in sand molds, head downwards, from steel of the
proper composition to give the required strength. They
were then annealed by being left in a furnace until brought
to a red heat, when they were removed and allowed to cool
gradually in the air. The interior of the cast shell was
seldom machined, except at the base end for the insertion
2 HIGH-EXPLOSIVE SHELLS
of the base fuse, and the exterior was ground or finished
in a lathe and grooved at the base end to form a seat for
the rotating band.
Types of High-explosive Shells. There are in use at the
present time four types of shells that may be said to be
high-explosive. The first, but not the most common, is
known as the high-explosive shrapnel shell. This type of
projectile, shown at A, Fig. 2, combines the principles of
both the high-explosive shell and the common shrapnel
shell, and has been used by some governments within the
SLOW-BURNING
MATERIAL
Machinery
Fig. 1. Original Cast-iron Spherical High-explosive Shell
past four or five years. In this shell, the head or fuse car-
ries a high-explosive charge and the matrix surrounding
the bullets is a high-explosive material capable of being de-
tonated by the detonation of the fuse. This projectile car-
ries a combination time and percussion fuse and a base
charge of black powder similar to the common shrapnel.
For use as a common shrapnel, the fuse and bullets are ex-
pelled without any detonation, the matrix serving to pro-
duce smoke as in the common shrapnel. The head or fuse
HIGH-EXPLOSIVE SHELLS
3
4 HIGH-EXPLOSIVE SHELLS
continues in flight and detonates upon impact, causing con-
siderable damage, and is capable of destroying the shield
used in protecting a field gun. In the event that the fuse
is set to explode upon impact, the high-explosive material
in the head and the matrix in the shell detonate together,
thus giving the effect of a high-explosive shell. The explo-
sive commonly used in the head and as a matrix in this
class of ammunition is trinitrotoluol, which is used in con-
nection with fulminate of mercury, or other similar mate-
rials necessary to start the detonation. Fig. 4 shows the
condition of one of these shells after being detonated upon
impact, this shell not having filled the function of a common
shrapnel shell. The projectile shown here is an American
3-inch caliber, high-explosive shrapnel weighing 15 pounds.
Common High-explosive Shell. The shell shown at B,
Fig. 2, is known as a common high-explosive shell, and is
the type used in medium-caliber field guns by the Russian
government. The fuse or exploder is inserted in the nose
end of the shell, and usually surrounded by a high-explosive
picric acid, lyddite, melenite, trinitrotoluol, etc. This
shell is used principally against fortifications, although it
can be used to some extent for field operations. It explodes
upon impact and possesses enormous destructive power.
Some idea of the great damage wrought by a modern high-
explosive shell will be obtained by referring to Fig. 5, which
shows the condition of an American 3-inch high-explosive
shell after bursting. The fragments were obtained by ex-
ploding the shell in an enclosed sand pit.
Delay-action Fuse Shells. The shell shown at C, Fig. 2,
is used in coast defense and field guns and carries a fuse
located in the base. When used by the American govern-
ment in field guns, it is equipped with a delay-action fuse and
carries from 3 to 30 per cent of its weight of high-explosive.
The lighter charged shells are used for repelling infantry
attacks, whereas, the heavier charged shells are used for
destroying fortifications. One of these types is used as an
armor-piercing shell; this contains a very large bursting
charge and is furnished with a quick-acting fuse. It is used
principally to repel attacks of light-armored vessels or for
HIGH-EXPLOSIVE SHELLS 5
attacking the upper works of heavily-armored ships. It ac-
complishes its purpose by exploding upon impact, driving
in the thin plates and destroying those parts not protected
by heavy armor.
The type of shell shown at D is also known as an armor-
piercing shell. This carries a much lighter explosive charge
than the shell shown at C, and is made with much thicker
walls. This shell carries a delay-action fuse, which per-
mits the projectile to pass through the armor plate and into
the interior of the vessel before exploding.
Construction of Modern High-explosive Shells. High-
explosive shells are made at present in a variety of shapes
and sizes, ranging all the way from 1.4 to 16 inches in diam-
eter and from 1 to 2400 pounds in weight. The shells used
by various governments also differ considerably in construc-
tion. For instance, the American government uses a solid-
point nose shell as shown at A, Fig. 3, which is almost the
same in construction as the armor-piercing shell and can be
used against light-armored cruisers or the upper works of
heavily-armored ships. The shell is provided with a rifling
band near the base and also with an inserted bronze plug
in which the base type of fuse is held. The type of fuse
used varies with the use to be made of the shell. For in-
stance, in mountain guns, howitzers, and mortars, a centri-
fugal type of fuse, as shown, is generally used ; whereas, for
high-velocity field guns, a ring-resistance fuse is generally
employed. The cartridge case and primer held in the base
are similar in construction to those used on shrapnel shells.
This type of high-explosive shell explodes upon impact only
and the cavity is filled with an explosive called explosive
"D" from its inventor Lieut.-Col. B. W. Dunn; it is also
sometimes known as "dunnite." Dunnite is not a sensitive
explosive ; consequently, quite a heavy detonating charge is
used. The detonating composition is made of picric acid
in various portions or T. N. T. (trinitrotoluol).
British 18-pounder Shell. The British 18-pounder high-
explosive shell is shown at B, Fig. 3. This shell is provided
with very thick walls and carries a charge of high-explosive,
generally lyddite. A nose fuse instead of a base fuse is
6
HIGH-EXPLOSIVE SHELLS
AMERICAN 3-INCH
A
BRITISH 18-POUNDER (3.29")
FRENCH 75 M.M.(2.95")
c
RUSSIAN 3-INCH
D
Fig. 3. Types of High-explosive Shells used by American, British, French,
and Russian Governments
HIGH-EXPLOSIVE SHELLS 7
used and the fuse operates on percussion only. In order that
the lyddite will be satisfactorily detonated, the fuse has an
extension known as a gaine, which continues into the cavity
of the shell for quite a distance. This gaine is filled with
three different detonating materials, each successive one
being more powerful than the last. In other words, this
shell is set off by what is known as the delay-action fuse.
This allows the shell to penetrate fortifications or earth-
works before it is detonated, and, consequently, enables the
explosion to have a much more destructive effect than if
it took place instantaneously upon impact. This particular
size of high-explosive shell is generally made from bar stock
and, in order to avoid chances of piping, a gas plug is in-
serted in the base of the shell, as shown. The cartridge
case and primer held in the base are the same as those used
on the shrapnel shell.
French 75-millimeter Shell. The now famous French
75-millimeter high-explosive shell is shown at C, Fig. 3.
This shell is made from a forging having comparatively
thin walls, and is hardened and heat-treated to increase its
elastic limit and tensile strength. It also carries in the nose
a delay-action fuse that is of interesting 'construction. The
cavity in the shell is generally filled with a high-explosive
known as melenite, the base of which is picric acid. The
melenite is poured into the cavity of the shell while in a
liquid form and solidifies upon cooling. The exploder,
shown extending from the end of the fuse into the explo-
sive, is filled with melenite in powder form. The character-
istics of the detonator and bursting charge have to be simi-
lar in order that the greatest possible shattering effect may
be produced. The fuse used in this shell is also of the delay-
action type and enables the projectile to penetrate earth-
works or fortifications before detonation takes place. The
cartridge case is similar to that used on the shrapnel shell
and is filled with smokeless powder (nitrocellulose) in stick
form.
Russian 3-inch Shell. The Russian 3-inch high-explo-
sive shell is shown at D, Fig. 3. The shell proper is made
from a forging that is heat-treated before or after machin-
II
0-w
W c
ARMOR-PIERCING SHELLS 9
ing, depending on the practice followed. It must have an
elastic limit of not less than 62,000 pounds per square inch
and a tensile strength of 118,000 pounds per square inch.
This shell also carries in its nose a detonating fuse, which,
however, differs considerably from any of the fuses pre-
viously illustrated. This fuse is practically instantaneous
and detonates the high-explosive material in the shell upon
impact. The cartridge case carries a heavy charge of
smokeless powder generally nitrocellulose and also a
primer in the base end somewhat similar in construction to
that used in the British shell. This projectile has a muzzle
velocity of over 1900 feet per second ; and, as the shell proper
is heat-treated, it has considerable destructive effect when
the high-explosive contained within it is detonated.
Armor-piercing Projectiles. Following the introduction
of iron sheathing for ships, it was found that the ordinary
cast-iron high-explosive projectile did not readily pierce the
plate, so that it became necessary to produce a projectile
that would do so. This was accomplished by Sir W. Pal-
liser, who invented the method of hardening the head of the
pointed cast-iron shell by casting the projectile point down-
wards and forming the head in an iron mold ; the metal at
the point being suddenly chilled became intensely hard,
while the rest of the casting remained comparatively soft.
The casting when partly cold was taken out of the mold
and thrown down into the sand, where it was allowed to cool
off gradually. These shells proved very effective against
wrought-iron armor, but had little effect against steel armor
plates. An improved shell was then devised which was
made from forged steel with a point hardened so as to
pierce the armor; this projectile is generally formed from
steel containing both nickel and chromium, and sometimes
tungsten. Armor-piercing shells are generally cast from a
special mixture of chrome-nickel steel, melted in a crucible
and afterwards forged into shape. The shell is then thor-
oughly annealed, bored internally, and turned on the exte-
rior in a lathe. The heat-treatment consists in hardening
the head of the projectile and tempering it in such a man-
ner that the rear portion is reduced in hardness so as to
10
ARMOR-PIERCING SHELLS
Fig. 5. Condition of a 3-inch American Common High-explosive Shell after
passing through a Steel Plate and into a Bank of Sand, and after
bursting. (Annual Report, Smithsonian Institution, 1914)
ARMOR-PIERCING SHELLS 11
render it extremely tough, whereas, the point is extremely
hard. There are two types of armor-piercing shells : One,
known as a shot, is used for piercing armor and carries a
light bursting charge; the other, known as a shell, carries
a much heavier bursting charge, is longer, has thinner
walls, and is much more destructive.
Capped Projectiles. As shown at D, Fig. 2, the armor-
piercing shell is similar in shape to the common high-explo-
sive shell shown at C, with the exception that the walls are
much thicker and the point is still thicker.. In order to
greatly reduce the air resistance encountered in flight,
armor-piercing shells are provided with a long pointed outer
covering for the head. It was also found that if an armor-
piercing shell having a hardened nose struck an armor plate
with great force, the force of the blow shattered the head
and made it ineffective, A soft steel cap placed on the shell,
supports the point and greatly improves the chances of the
projectile getting through a hard armor plate unbroken.
One of the plausible theories advanced as to the ineffective-
ness of an uncapped head is : When an uncapped projectile
strikes the extremely hard face of a modern armor plate,
the whole energy of the projectile is applied at the point
and the high resistance of the face of the plate puts the
very small arc at the point of the projectile to a stress
greater than the metal can resist. The point is therefore
broken or crushed and the head of the projectile is flattened ;
this greatly reduces the penetrating power and results in
the point of the projectile being practically welded to the
armor plate. When a capped projectile strikes a hard plate,
the resistance of the plate is distributed over a greater area,
and the point is supported by the cap. Consequently, the
point is not deformed and passes through the plate.
The specifications for the test governing the manufacture
of armor-piercing projectiles are very stringent and re-
quire that the shell perforate a hard-face armor plate as
thick as the caliber of the projectile without breaking the
point. In other words, a 6-inch projectile is required to
completely pass through a 6-inch armor plate in an un-
broken condition.
12 ARMOR-PIERCING SHELLS
General Methods of Manufacture. At present, there
are two general methods of manufacturing high-explosive
shells. One is to make the shell from bar stock, removing
the excess material to form the cavity by means of high-
power drilling machines ; the other is to forge the shell to
approximately the correct shape. Until within the last few
years, cast-iron shells were used quite extensively; these
were cast in sand molds using a core to form the cavity.
Great difficulty, however, was experienced in obtaining a
casting free from flaws and other imperfections, so this
method has generally been superseded by either the forged
or bar-stock shell. When the shell is made from bar stock,
it is usually necessary to fit a gas plug in the base end to
eliminate any chances of piping. At present, cast-iron
shells are still used for target practice.
High-explosive shells are made in three distinct types.
Those with a solid base carrying a nose fuse, those with a
solid nose carrying a base fuse, and those with an open nose
and base carrying a nose fuse. If the shell is intended to
carry a nose fuse, the base end is shaped in forging by the
press and the nose subsequently formed to shape by a nos-
ing-in die. In small shells of about 2 inches in diameter, the
nose when red-hot can be spun over in the lathe by properly
formed tools. However, it is usually closed in by a press.
For base fuse shells, the nose is produced by the forging
machine and the base is subsequently formed by pressing
the metal to the required shape.
Operations on British Forged Shells. Generally speak-
ing, the operations on a British high-explosive shell when
made from f orgings are as follows : Bar stock of the re-
quired diameter is first cut off into billet lengths, which are
heated to about 1900 degrees F. (about 1040 degrees C.),
and by subsequent piercing and drawing operations are
drawn out to the correct length and diameter. Following
this, the mouth end and base end are trimmed and faced off.
Then several operations are performed on the external di-
ameter of the shell, such as turning, grooving, etc. The shell
is then held in a chuck and several operations are performed
on the cavity, after which it is nosed-in ; the final operations
ARMOR-PIERCING SHELLS 13
consist in machining the nose, pressing on the band, ma-
chining it, testing, etc. After the shell has been completely
machined, it is filled with lyddite. In filling the shell, great
precautions are taken to prevent the melted lyddite (which
contains picric acid) from coming into contact with certain
materials, such as combinations of lead and soda, which pro-
duce sensitive picrates. The shells are consequently painted
externally with a special non-lead paint and lacquered inter-
nally with a special lacquer. The picric acid is then melted
in a pot, the temperature being carefully controlled, and
certain ingredients are added to reduce the melting temper-
ature of the acid. The melted material is then poured into
the shell through a bronze funnel, the latter forming a space
for the exploder. In cooling, the material solidifies into a
dense hard mass.
Operations on French Forged Shells. The French high-
explosive shell was adopted in 1886. The high-explosive
used in this shell was melenite, which was originally put
into an ordinary cast-iron common shell having thick walls.
Afterwards, a forged steel thin-walled shell was introduced,
as shown at C, Fig. 3 ; this is hardened and heat-treated in
order to give it the correct tensile strength. The operations
on the French shell differ from those on the British shell
in that no machining is done on the inside of the shell or the
cavity. The general manufacturing methods on this shell
are first cutting off a billet of the required length, heating,
and forging. Usually the forgings are pickled; then the
base end is faced and centered, the external diameter is
turned, after which the shell is nosed-in. Following the
nosing-in operation, the shell is hardened and tempered,
after which it is faced off on the nose end, bored, reamed,
threaded, and finally ground or turned on the external diam-
eter ; after this the rifling groove is cut and the rifling band
pressed in and turned to shape. In order to avoid the for-
mation of picrates, the interior of the shell is lacquered and
the external surface painted with a non-acid paint. The
melenite is then melted and poured in.
High-explosive Shell Fuses. Various types and forms
of fuses or detonators are used in high-explosive shells, some
14
FUSES AND PRIMERS
governments using a plain type of concussion fuse held in
the base end of the shell, and to which no gaine is attached ;
this fuse is set off upon the impact of the shell against for-
tifications or other obstructions. Others use percussion
fuses of extremely complicated design which are provided
with exploders that extend down into the cavity in the shell ;
these carry a detonating primer and exploding material for
detonating the high-explosive contained in the cavity of the
shell. Where ordinary black powder is used to burst the
shell, a high-power detonator is not necessary. The direct-
action, or impact, fuses are more simple in construction
SAFETY PLUG
CONCUSSION SPRING
NEEDLE
BOD
EEDLE AND NEEDLE DISK
DETONATING
COMPOSITION
WRENCH HOLES
PRESSURE PLATE
Machinery
Fig. 6. Common Types of Concussion Fuses used in Nose and Base of
High-explosive Shells
than the combination time and percussion fuses, and they
are usually made of material that will withstand considera-
ble pressure without crushing.
High-explosive shell fuses may be divided into two dis-
tinct groups : Those that explode instantaneously upon im-
pact and those that explode shortly after impact, or, in other
words, those in which the detonating action is slightly de-
layed. From the standpoint of design and operation, these
groups are subject to still further divisions. For example,
some fuses are started or "unloaded" by the gas pressure
FUSES AND PRIMERS
15
- C
Machinery
in the gun, others depend on rotation, and some depend on
a combination of both ; then there are types employing split
rings, centrifugal bolts, springs, etc., or a combination of
two or more actions.
Common Type of Concussion Fuse. A common type of
concussion, or direct-action, fuse that fits in the nose of
the shell and is set off upon impact is shown at A, Fig. 6.
The fuse body and other important members are made from
steel of sufficient strength to be discharged from the gun
without rupture; but, upon striking, the needle disk is
crushed in and the needle explodes the detonator, which, in
turn, explodes the
powder in the base of
the fuse. At B is
shown the common
type of concussion fuse
used in the base of
high-explosive shells.
Before firing, the
needle pellet is held Fig. 7. Base Fuse used in American Small-
by a central spindle and Medium - callber nigh-expiosive shells
that has a pressure plate attached to its rear end. A cen-
trifugal bolt is also inserted for additional safety, which is
released by the rotation of the shell. In action, this fuse
works as follows : On the discharge of the projectile from
the gun, the gas pressure pushes in the pressure plate so
that the central spindle is carried forward, unlocking the
centrifugal bolt. The needle pellet is then free to move
forward and explode the detonating cap when the shell
strikes. These two types of fuses are not very extensively
used at the present time, and have been superseded, in gen-
eral, by more complicated but effective fuses.
American Base Percussion Fuse. In American high-ex-
plosive shells fired from one- and two-pounders, as well as
from six-pounders and 2.38-inch field guns, the type of fuse
shown in Fig. 7 is used. This fuse is of simple construction
and depends for its action on the expanding of a split ring A.
As the primer end of the fuse is toward the interior of the
shell, the flame passes from the priming charge B directly
16
FUSES AND PRIMERS
to the bursting charge in the shell without passing through
the body of the fuse itself. The primer cup contains the
percussion composition and priming charge, and is enclosed
at its outer end by a brass disk C secured in place by crimp-
ing over the outer end of the primer holder, or brass closing
screw D. The act of arming this fuse is simple, and de-
pends on the expanding of the split ring, which is accom-
plished when the shell strikes a solid body.
Centrifugal Type of Base Percussion Fuse. In the
case of ring-resistance fuses, or, in fact, in any fuse the
action of which depends on the longitudinal stresses de-
veloped by the pressure in the gun, the conditions of safety
in handling and certainty of action are not all that could
GUN COTTON
DETONATING COMPOSITION
Machinery
Fig. 8. Frankford Arsenal Centrifugal Type of Base Per-
cussion Fuse
be desired. A fuse that is armed by the centrifugal force
developed by the rotation of the projectile, and which is
safe until the maximum velocity of rotation is nearly ob-
tained, is the Frankford arsenal fuse shown in Fig. 8, where
a separate view of the expanding centrifugal plunger pre-
sents the firing pin in the armed position.
This fuse is used in shells fired from mountain guns,
howitzers, and mortars. It is made up of the body A and
the closing screw B, which are held in the steel stock C;
this stock also carries the detonating charge. The primer
or detonating agent is also held in the nose of the fuse, and,
to reach the exploder, the flame passes through a small vent
in the primer closing screw D to the guncotton, which f acil-
FUSES AND PRIMERS 17
itates and increases the igniting effect. The centrifugal
plunger, shown in the armed position at H, is made in two
parts. When the fuse is at rest, these are held together
by the pressure of a spiral spring F contained in the cylin-
drical bushing G secured to each end of the plunger halves.
The spring exerts its pressure on half of the plunger
through the bolt 7. Pivoted in a recess in one half of the
plunger is the firing pin J, which, when the fuse it at rest,
is held with its point below the front surface of the plunger
by the lever action of the link K that is pivoted to the
other half. When subjected to the action of centrifugal
force developed by the rapid rotation of the projectile in
passing from the bore of the gun, the two halves of the
plunger separate. This separating movement causes the
rotation of the firing pin /, the point of which is now held
in advance of the front surface of the plunger, to pierce
the brass primer shield and ignite the detonating composi-
tion. When the fuse is armed, the end of the link K rests on
the pivot of the firing pin, thus affording support to the
firing pin when it strikes the percussion primer. The
amount of separation of the plunger parts is limited by
the nut M coming to a bearing on a shoulder in the bush-
ing G, and thus preventing the diameter of the expanding
plunger from equalling the full diameter of the hole in the
fuse body. A stud screwed into the head of the fuse stock
engages a corresponding slot cut through the bottom of
both plunger halves and insures the rotation of the plunger
with the shell. The strength of the spring F is adjusted
so that the fuse will not arm until its rapidity of rotation
is a certain percentage of that exerted in the shell in which
it is used, and so that it will surely arm whenever the
rapidity of revolution approximates the speed of rotation
of the shell when fired. In the case of the parts of the
plunger being accidentally separated and the fuse armed
by a sudden jolt or jar in transportation or handling, the
reaction of this spring will immediately bring the plunger
back to its unarmed position.
British High-explosive Fuse. The fuse shown in Fig. 9
is known as the British 100-graze high-explosive fuse, and
18
FUSES AND PRIMERS
is used in British high-explosive shells that are fired from
field and mountain guns. This fuse explodes upon impact
only and screws into the nose of the shell; all the parts,
except the adapter and gaine, are made from brass or
bronze. This fuse operates as follows : When the shell is
Machinery
Fig. 9. British No. 100 Graze High-explosive Shell Fuse
fired, and before it commences its rotary motion imparted
by the rifling in the gun bore, the impact of the explosive
charge in the case causes the combined top and bottom de-
tent A and B, respectively, to drop back and compress the
detent spring C. The detent assembly is made in two
FUSES AND PRIMERS 19
pieces ; and, as the stem A is free to move out of alignment,
it drops to one side, by the action of gravity, when it is
forced back. It is caught by the edge of the counterbored
hole and prevented from taking its original position. By
this time, the centrifugal action of the shell throws centri-
fugal bolt D, the path of which is now clear, out of the way
of the graze pellet E. The only member that now prevents
detonation is the hair spring F, so the slightest impact
causes the relatively heavy graze pellet to jump forward
and explode the shell. The primer that is held in the coun-
terbored end of the graze pellet is exploded upon impact
with needle G, and from here the flame extends down into
the other explosives in the gaine. The primer in pellet E
is loaded with a composition composed of 45 parts chlorate
of potassium, 23 parts sulphide of antimony, and 32 parts
fulminate of mercury. The different constituents are meas-
ured by weight, and are loaded into the primer cup under
a pressure of 600 pounds, after which the cup carrying the
explosive charge is dried.
Should the primer in the pellet E, for any reason, fail to
explode, a second detonation takes place simultaneously.
As shown by the view to the right, the lower end of pellet
E is tapered and seated in a cross-hole in the percussion
pellet H. When the graze pellet moves forward, pellet H
is released and the centrifugal action combined with spring
I drives the pellet carrying needle / against primer K, ex-
ploding it. The flame passes through four small holes in
the needle holder L, thence into the chamber and down into
the gaine containing the detonating charges.
The gaine is held to the fuse body by adapter M. Its
three chambers, N, 0, and P, contain different high-explo-
sives, each succeeding one being of greater power than the
last. Chamber P is filled with lyddite in flake form. The
flame from the detonating primers first explodes the ma-
terial in chamber N, then that in chamber 0, and then that
in chamber P, which causes such a terrific shattering effect
that the lyddite in the shell is detonated and blows the shell
to atoms some parts to the fineness of sand. It is stated
upon good authority that, after a shell has been detonated,
20
FUSES AND PRIMERS
it is impossible to find the gaine or its parts, so terrific is
the effect of the explosion.
Russian High-explosive Fuse. The Russian high-explo-
sive fuse or detonating head used in high-explosive shells
is shown in Fig. 10 ; the gaine is a part of the head and ex-
tends into the explosive material in the cavity of the shell.
Machinery
Fig. 10. Russian High-explosive Shell Detonating Head
This fuse operates in the following manner : The force of
impact of the shell against a solid body overcomes the re-
sistance of spring A and stirrup B, allowing striker rod C
to move forward into the cavity occupied by spring A.
Attached to the lower end of striker rod C is a detonator
pellet D, which carries a charge of mercury fulminate, and,
in coming in contact with the steel needle E, is exploded.
MELENITE POWDER
tVTT
Machinery
Fig. 11. French Detonating Fuse for Use in 75-millimeter
High-explosive Shells
When exploded, pellet D is midway along the interior of the
"tetryl" cartridge / that surrounds the striker rod C, so
that the latter is detonated* and, in turn, explodes the high-
explosive material held in the cavity of the shell. Needle E
is held in a steel plug F, which is kept from moving up with
the striker rod C by a striker casing G crimped around it,
FUSES AND PRIMERS 21
and extending up through the body of the fuse, coming in
contact with the lower face of the head plug H. In order
that the body of this detonator will be capable of resisting
considerable shock, it is generally made from alloy steel
with a tensile strength of about 110,000 pounds per square
inch.
French High-explosive Fuse. A high-explosive shell
fuse of the delay-action type used in the French 75-milli-
meter high-explosive shell is shown in Fig. 11. This is
provided with a safety head and is carried in the nose of
the shell. In action, this fuse works as follows: On the
discharge of the projectile from the bore of the gun, the
gas pressure overcomes the resistance of spring A, causing
bushing B to drop back ; the stirrup C, which is held to it,
then grips the head of the plunger D. The plunger D com-
pletely envelopes the firing pin E and prevents the detona-
tor F from being accidentally discharged. When this
plunger is withdrawn, it exposes the firing pin E, which
is riveted to the retainer G, and does not move with the
plunger.
The fuse is now in the armed position, so, as soon as the
projectile strikes a solid body, the resistance of springs /
and J is overcome and the primer F makes contact with
the firing pin E. The flame from the primer F ignites the
guncotton K and the powder surrounding it ; this ignites the
compressed gunpowder in cups L and M, which results in
quite a powerful explosion and explodes the detonating com-
position in cup N; this, in turn, explodes the detonator 0,
which is filled with melenite in flake form. The fuse does
not detonate the high-explosive composition in the shell in-
stantaneously, but causes a series of explosions, finally re-
sulting in the detonation of the melenite in the shell by the
exploder that extends into it. All the working parts of
this fuse are made from brass or bronze with the exception
of the safety cap P, nose Q, cup R, and exploder cup S;
these are made of steel.
Loading Propelling Charges in Guns and Howitzers.
In the early cannon, the spherical shot and powder charges
were rammed in from the muzzle of the gun the same as in
loading small arms. It was not until 1845 that a success-
22
FUSES AND PRIMERS 23
ful breech-loading gun was designed ; in this case, the pro-
jectile, which bore a marked resemblance to the present-day
type, was placed in the gun from the breech end with a pro-
pelling charge of black powder packed in behind it, the vent
being closed by a hinged door. Following this, several
types of breech-closing mechanism were developed, and, in
England in 1854, the Armstrong breech-loading gun was de-
signed. The projectile and propelling charge, however,
were still made up in separate units, and it was not until
some time later that fixed ammunition was used in field
guns. In early cannon, the barrels were made from either
bronze or cast iron, bronze being used for field guns and
cast iron for large coast artillery. These two metals were
subsequently abandoned, forged steel being used in their
place.
Fixed Ammunition. Fixed ammunition is the name
given to that class of shells in which the propelling charge
for the projectile is held in a cartridge case attached to the
rear end of the projectile. In other words, the projectile,
propelling charge, and firing member or primer form a com-
plete unit. The diagram at A, Fig. 12, shows a sectional
view of a 3-inch field gun with the complete round of am-
munition inserted in the breech. It will be noticed that the
gun is chambered to receive the projectile and cartridge
case, and carries a breech-block containing the striker
mechanism. Upon the operation of the striker mechanism,
firing pin a hits primer 6, igniting the percussion cap in its
head, which, in turn, ignites the black-powder charge in the
body of the primer itself. The propellant in the cartridge
case c is now ignited and almost instantly converted into
a gas. The gas thus formed occupies a much greater vol-
ume than the original material, with the result that the
projectile e is started on its journey through the bore of the
gun.
As soon as the projectile starts forward, the copper
rifling band d is forced into the rifling grooves in the bore
of the gun, which are located in a helical path. This results
in the projectile being rotated at the same time that it ad-
vances. In addition, the rifling band also centers the pro-
24 FUSES AND PRIMERS
jectile and prevents the propelling gas from escaping past
it. Modern propellants, by virtue of their ingredients, are
of the slow-burning variety ; consequently, the gas pressure
increases, with the result that the projectile increases in
velocity from the time that it leaves the breech until it
reaches the muzzle of the gun. To provide for this, the
rifling grooves in some guns increase in pitch as they reach
the muzzle of the gun. For example, in the 3-inch, Ameri-
can, quick-firing field gun, the rifling grooves start at the
breech with a twist of one turn in 50 calibers and increase
to one turn in 25 calibers at a distance of 2i/ 2 calibers from
the muzzle. Therefore, as the velocity of the projectile is
increased, the speed of rotation upon its axis is accelerated ;
this partly accounts for the comparatively flat trajectory
of the modern high-power quick-firing gun in comparison
with the older and less efficient guns.
Loading Howitzers and Mortars. A howitzer differs
from a quick-firing field gun in several ways : The barrel
is much shorter; no cartridge case is used (except for me-
dium-caliber howitzers, where a short case is sometimes
used) ; the muzzle velocity is only about one-half that of a
quick-firing gun of the same caliber ; and a howitzer is used
for high-angle firing, particularly against troops protected
by entrenchments or other shelter. The diagram B, Fig. 12,
shows a section through the barrel of a 4.5-inch howitzer.
The projectile / is not fixed to the cartridge case g; in fact,
it is separated from it. The difference between this cart-
ridge case and the one shown at A is in length only; the
length of this cartridge case is about one-half the caliber.
The howitzer cartridge case carries a comparatively light
propelling charge of smokeless powder h, which is held in
the case by wads. Having the ammunition arranged in this
manner makes it possible to vary the charge according to
the results wanted. In larger-bore howitzers, 6-inch caliber,
a charge of powder in the form of doughnuts or large disks
is used ; these are placed directly in the breech of the gun,
and no cartridge case is used.
A type of gun that bears a marked resemblance to the
howitzer is the mortar, which is classified as field or
if!
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25
26
FUSES AND PRIMERS
pelling charges are separated. Fig. 13 shows a sec-
tion taken through the chamber and barrel of a 6-inch
rapid-fire gun. Here, the projectile i is separate; and
located between the projectile and the breech-block is
a propelling charge of smokeless powder and detonating cap
contained in silk bags ;, the number of bags depending on
the size of the gun and the weight of the charge put up in
each. These bags are made from raw silk with the ends
made double-ply, and between the two pieces at each end
BLACK POWDER
Machinery
Fig. 14. Friction, Electric and Percussion Primers
is placed a priming charge of black powder quilted in, in
squares of about 2 inches, and uniformly spread over the
surface. The charge used for propelling a projectile of this
particular size of gun weighs about 24 pounds ; consequently,
only two bags would be needed. The obturator h acts as
a gas check and at its rear end carries the electric primer.
The powder charge is ignited by means of a friction or elec-
tric primer shown at A, B, and C, Fig. 14. The primer, of
course, is not a part of the propelling charge, but is held
in the breech-block of the gun. In larger-bore guns, several
bags of smokeless powder are inserted ; for instance, in the
FUSES AND PRIMERS 27
16-inch American gun, six bags containing a total of 666.5
pounds of smokeless powder are used.
Friction, Electric, and Percussion Primers. Various
types of primers are used in howitzers and field guns for
igniting the propelling charges. For guns using fixed am-
munition, the primer is carried in the base of the cartridge
case; whereas, for guns firing loose projectiles, the primer
is held in the breech-block. Inasmuch as large- and me-
dium-size caliber projectiles are discussed here, two of the
principal types of primers used in the breech-blocks are
described.
Friction Primers. Fig. 14 shows the common type of
friction primer, which may be fired by friction or electric-
ity. As the f rictional and electrical elements are independ-
ent, this primer may be fired by friction should it fail to fire
by electricity. This primer comprises a brass case a held
in the breech-block of the gun, and carrying a case b en-
closing the firing or igniting elements. When used as a
friction primer, an annular pellet c of friction composition
is pressed into the inner case b and rests on a vulcanite
washer d, which prevents it from crumbling when the firing
rod e is pulled to ignite the primer. The inner end of the
firing rod e is loosely surrounded by a serrated cylinder g,
which is embedded up to the serrations in the friction com-
position. The inner end of the firing rod is provided with
a head that operates upon the cylinder g, and these parts
are securely held in place by forked lever h and nut i; this
end is shown enlarged at B.
In operation, when the firing rod e is pulled, the serrated
cylinder g is drawn through the composition c and ignites
it. As the conical end of the cylinder is then drawn to its
seat in the rear part of the primer, it prevents the escape
of gas at the rear. The flame from the friction composition
passes through vents in the closing nut i and ignites the
priming charge of compressed and loose black powder in the
body of the primer. The resulting explosion blows out the
cemented brass cup j in the mouth of the primer and allows
the flame to pass through the breech-block to the propelling
charge in the breech of the gun.
28 FUSES AND PRIMERS
Electric Primers. In order to adapt this primer for
electric firing, the rod e is covered with an insulating cylin-
der k and enters the primer through a vulcanite plug I. The
rod e is in electric contact with the serrated cylinder g, but
this is insulated from the primer body by a washer d and the
pellet of friction composition, which is a non-conductor of
electricity. The electric circuit is completed by a platinum
wire m soldered to the fork h and nut i and surrounded by
an igniting charge of guncotton.
In operation, when the primer is inserted in the gun, the
insulated button n on the rod e is grasped by an electric
contact piece through which the electric current passes. The
passage of the electric current then heats the platinum wire,
igniting the guncotton and the priming charge of powder.
Percussion Primers. In fixed ammunition where the
cartridge case forms a unit with the projectile, the firing
is done by means of a primer held in the cartridge case ; D,
Fig. 14, shows the primer used in the head of American
3-inch cartridge cases. This is known as the 110-grain per-
cussion primer, and consists of a brass case o resembling
in shape a small-arms cartridge case, in which a percussion
cap is held. The head or rear end of the primer case is coun-
tersunk to form a cup-shaped recess in which the percussion
primer proper d is located. The latter consists of a cup,
anvil, and percussion composition, which is composed of
the following ingredients:
Ingredients Per Cent
Chlorate of Potash 49.6
Sulphide of Antimony 25.1
Glass (ground) 16.6
Sulphur 8.7
Owing to the danger involved in the handling of mixtures
containing fulminate of mercury, the Frankford arsenal
has abandoned this ingredient and substituted the ingre-
dients just given for the service primers.
The percussion cap recess is connected with the interior
of the primer case by two small vents. The body of the case
contains 110 grains of black powder that constitutes the
rear "priming" or igniting charge for the smokeless-powder
FUSES AND PRIMERS
29
propellant. This black powder is inserted in the case under
a pressure of 36,000 pounds per square inch, and is pressed
into the primer body around a central wire which is then
withdrawn, leaving a longitudinal hole the full length of the
powder charge. Eight radial holes are then drilled through
the primer body and compressed powder, thus affording six-
teen vents for the free exit of the black-powder flames to
the smokeless-powder charge. After filling the case, the
front end is closed by a cardboard wad covered with shellac
and the radial perforations are covered by a tin-foil wrap-
per so as to retain any loose black powder and exclude
moisture.
In action, the firing pin hits the percussion cap and ex-
plodes it. This ignites the black-powder charge, and the
Machinery
Fig. 15. Percussion Primer used in British Cartridge Cases
flames from the latter shoot out through the vents in the
case and ignite the smokeless-powder charge. In order to
make the combustion of the smokeless powder complete, a
second igniting or priming charge is generally used. In the
3-inch shell, this additional charge consists of 14 ounce of
black powder which is contained in a disk-shaped bag placed
in the case directly in front of the smokeless-powder charge.
British Percussion Primer. A percussion primer that
differs considerably from that illustrated at D, Fig. 14, is
shown in Fig. 15; this primer is used in British 18-pound
cartridge cases. It comprises a brass cup A threaded on the
external diameter so as to screw into the pocket in the head
30 FUSES AND PRIMERS
of the case, and recessed and threaded to receive the anvil
B. This, in turn, is counterbored to receive a brass ball C
and is also provided with three fire holes. It is backed by
a plug D that is sealed with a paper disk E secured with
Pettman's cement. Seated on the head of anvil B is the
percussion composition, which is pressed into the soft brass
cup F, and inside of which is a tin-foil washer. The percus-
sion composition, known as the 1.2-grain composition, con-
sists of the following ingredients :
Ingredients Per Cent
Sulphide of Antimony 54.5
Chlorate of Potash 36.5
Glass (ground) 3.0
Powder (mealed) 3.0
Sulphur 3.0
In the front end of the primer enclosed by a brass closing
disk G is a charge of RFG 2 powder. Separating the closing
disk and the powder is a paper disk H secured with Pett-
man's cement. The closing disk G is held in place by spin-
ning over the front edge of the cup A.
In action, the firing pin comes directly in contact with the
percussion cap F, exploding it and causing the flames to
pass through the vents in the anvil B and the plug D. The
paper disk E is thus ignited, together with the powder
charge in the front end of the primer. The resulting pres-
sure forces out the center of the closing disk G, which is
weakened by six radial slots. The flame then passes to the
secondary powder charge in the base of the cartridge case,
thus effecting complete combustion of the propelling charge.
In order to prevent the escape of gas back through the vents
in the primer before complete combustion has taken place, a
soft brass ball C is inserted in the anvil. As soon as the
powder in the front of the primer is ignited, the resultant
back pressure forces the ball into the circular seat in the
anvil and effectively prevents the further escape of gas.
Combination Electric and Percussion Primer. The
United States Navy uses, in rapid-fire guns, a combination
electric and percussion primer of the type shown at C, Fig.
14. When fired by percussion, the percussion cap r is not
FUSES AND PRIMERS 31
struck directly by the firing pin, but the point of the pin
forces in the head of the cup t and this, in turn, advances
plug s. The electric ignition is effected through the brass
cup t to which one end of the platinum wire u is soldered.
A small quantity of guncotton surrounds this wire. Electric
contact is made with cup t by the insulated firing pin of the
gun. This cup is insulated from the body of the primer
by the cylinder iv and bushing v, both of which are made of
vulcanite. The brass contact bushing y to which the other
end of the platinum wire is soldered completes the electrical
connection.
CHAPTER II
EXPLOSIVES, DETONATORS AND FULMINATES
REFERENCE to Fig. 3 will show that a high-explosive shell
of the fixed-ammunition type comprises four principal parts ;
namely, the projectile, fuse (detonating), cartridge case,
and primer. The projectile carries the high-explosive that,
when detonated, produces such a powerful shattering effect
that the steel shell is blown into atoms. The high-explosive
in the shell is detonated by other very powerful explosives
contained in the gaine of the detonating fuse. In the fuse
proper, as many as four classes of explosives are used;
namely, fulminate of mercury, black powder, picric acid,
and compounds of a similar nature so combined as to make
their explosive effect of different strengths. The cartridge
case carries a propellant, usually nitrocellulose or nitrogly-
cerine, that is put up in the form of flakes, long tubes, per-
forated grains, or flat strips. It also contains one or two
charges of common black powder. One charge is located
between the smokeless powder and the projectile; the other
is located next to the primer pocket and assists the priming
charge in effecting complete combustion of the propelling
charge. The primer usually contains two explosive agents ;
namely, fulminates or chlorates, and black powder.
Classification of Explosives. The explosives used in
high-explosive shells, cartridge cases, fuses, and primers,
may be divided into three general classes: Progressing or
propelling explosives, known as "low explosives"; detonat-
ing or disruptive explosives, known as "high-explosives";
and detonators, known as "fulminates" or "chlorates." The
first of these includes black gunpowder, smokeless powder,
and black blasting powder; the second, dynamite, nitro-
glycerine, guncotton, etc.; the third, fulminates and chlor-
32
EXPLOSIVES AND DETONATORS 33
ates. In all classes of explosives, the effect of the explosion
is dependent on the quantity of gas and heat developed per
unit of weight, the volume of the explosion, the rapidity of
reaction, and the character of the confinement, if any, in
which the explosive charge is placed.
Black Gunpowder. The most common of all explosives
is black gunpowder. The earliest known use of gunpowder
was in the sixteenth century, at which time it was used in the
form of fine powder or dust. No marked improvement was
made in this explosive until 1860, when General Rodman,
of the Ordnance Department of the United States Army,
discovered the principle of progressive combustion ; this con-
sisted in using larger grains of greater density so that the
rate of combustion could be more uniformly controlled. The
increased density diminished the rate of combustion, so that
black powder in this form developed less gas in the first
instant of combustion and the volume of gas increased as
the projectile moved through the bore of the gun. Black
gunpowder is usually made up of a mechanical mixture of
niter, charcoal, and sulphur in the proportions of 70 parts
niter, 15 charcoal, and 10 sulphur. The niter furnishes the
oxygen to burn the charcoal and sulphur, the charcoal fur-
nishes the carbon, and the sulphur gives density of grain to
the powder and lowers its point of ignition.
The manufacture of black gunpowder is comparatively
simple. The ingredients are ground and pulverized, after
which the correct proportions of each ingredient are inti-
mately mixed in an incorporating mill consisting of two
heavy iron wheels mounted to run in a circular bed; the
product is called a "mill cake." The mill cake is then sub-
jected to pressure in a hydraulic press and forms what is
known as a "press-cake." The cake from the press is
broken up into grains by passing through rollers and the
grains are graded by passing through sieves. The grains
are glazed by rotating in drums with or without graphite,
which gives a uniform density to the surface. When spe-
cial forms are to be given to the powder, dies are used to
obtain the desired shape ; this is done after the powder has
been thoroughly mixed and formed into press-cake.
34 EXPLOSIVES AND DETONATORS
Black powder or gunpowder is used in primers, fuses, and
also in the cartridge case as an additional priming charge
for completing the combustion of the propelling charge. In
the early use of high-explosive shells, black gunpowder was
also used as a bursting charge, but in recent years this has
been supplemented by other and more powerful high-explo-
sives.
Smokeless Powder. The modern smokeless powders
are put up into many forms, but all have the same base,
namely guncotton. The invention of guncotton is credited
to a German chemist Schoenbein, who, in 1846, discovered
a substance that he called "cotton powder." Improvements
were later made in the manufacture of guncotton by Gen-
eral Von Lenk and Sir Frederick Abel. Two of the prin-
cipal smokeless powders are nitrocellulose and nitrogly-
cerine. While the base of these is guncotton, the final
stages in their manufacture are different; for instance, in
the manufacture of nitroglycerine, a mineral jelly is added.
Manufacture of Guncotton. In the manufacture of
guncotton, the short fiber of the cotton that is detached from
the cotton seed rather late in the process of removal is used.
After being bleached and purified, this is run through a
picker which opens up the fiber and breaks up any lumps ;
it is then thoroughly dried, when it is ready for nitration.
The most generally used method of nitration consists in
putting the cotton into a large vessel nearly filled with a
mixture of nitric and sulphuric acid. The sulphuric acid
is used to absorb the water developed in the process of
nitration, which would otherwise dilute the nitric acid too
much. After a few minutes immersion, the pot is rapidly
rotated by machinery and the acid permitted to escape. In
the process of nitration, the cotton has not changed its ap-
pearance, but has become a little harsh to touch. The ni-
trated product is then washed in a preliminary way, re-
moved from the nitrator, and repeatedly washed and boiled
to remove all traces of free acid. The keeping qualities of
smokeless powder are dependent on the thoroughness with
which it is purified. At this stage of the manufacture, at
least five boilings, with a change of water after each boil-
EXPLOSIVES AND DETONATORS
35
ing, covering a total of forty hours, is necessary. Follow-
ing this preliminary purification, the cotton is cut into still
shorter lengths by being repeatedly run between cylinders
carrying revolving knives. This operation is necessary, as
Fig. 16. Boomer & Boschert Guncotton Press
the cotton fibers are tubes, making it difficult to remove the
traces of acid from the interior unless they are of very short
lengths. After being pulped, the cotton is given six more
boilings with a change of water after each, followed by ten
36 EXPLOSIVES AND DETONATORS
cold-water washings. The completed material is then
known as guncotton or pyrocellulose.
Before adding the solvent (acetone), the guncotton must
be completely freed from water. This is partly accom-
plished in a centrifugal wringer, but is completed by com-
pressing the guncotton into a solid block and forcing alcohol
through the compressed mass. To convert the guncotton,
or pyrocellulose, into nitrocellulose, ether is added to the
pyrocellulose thus impregnated with alcohol, the relative
proportions being about two parts of ether to one part of
alcohol, by volume. After the ether has been thoroughly
incorporated in a kneading machine, the material is com-
pressed into blocks. This is generally accomplished in a
hydraulic press; a machine especially designed for this
purpose is shown in Fig. 16. This press is built by the
Canadian Boomer & Boschert Press Co., Ltd., and is capable
of exerting a pressure of 150 tons on the material. It has
three sets of dies, A, B, and C, which are held on a separate
column on the press upon which they revolve ; also two sets
of punches or male dies, one set D being used for pressing
the cotton and the other set E for ejecting it after pressing.
The base of the machine is of cast iron, through which a
number of small holes are drilled to allow drainage of the
water from the cotton. The chief advantage of this press
is that, being provided with three sets of dies, it is possible
to load one set of dies while another is being pressed, and
from the third, the cotton is ejected, thereby making the
operation practically continuous. This press is operated by
a pump giving a pressure of 1500 pounds per square inch.
The size of the compressed blocks varies ; in some cases,
these blocks are made 10 inches in diameter by 15 inches
long, or are made of square section. In this operation, the
pyrocellulose loses the appearance of cotton and takes on
a dense horny appearance, forming what is known as a
colloid. The colloid 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 grains of the
required length. The grains are subjected to a drying
process, which removes nearly all the solvent (acetone) and
EXPLOSIVES AND DETONATORS
37
leaves the powder in a suitable condition for use. The dry-
ing process is a lengthy one, taking as much as four or five
months for the larger grain powders. Upon completion,
the powder is blended and packed in air-tight boxes.
Cordite. Cordite is the form in which smokeless pow-
der is used by the English government and is composed of
58 per cent nitroglycerine, 37 per cent guncotton, and 5
per cent vaseline. The vaseline renders the powder water-
proof and improves its keeping qualities. For use in can-
non, cordite is made into long thick rods that are tubular
in form or in the form of perforated cylinders; for heavy
guns, a powder called cordite M. D. has lately been intro-
duced ; this composition consists of 30 parts nitroglycerine,
65 parts guncotton, and 5 parts vaseline. The reduction in
Ma-oJiinery
Fig. 17. Form and Size of Grain for Smokeless Powders
the percentage of nitroglycerine was necessary because
of the desire to lower the temperature of the explosive
and the consequent erosion in the bore of the gun.
Forms of Smokeless-powder Grains. The form of grain
in which smokeless powder is made differs in various coun-
tries. In foreign countries, especially in Germany, nitro-
cellulose in the form of long tubes similar in shape to maca-
roni are used. Fig. 17 shows a few of the many forms in
which smokeless powder is put up. A shows a tube, which
is sometimes two feet long; usually, however, the nitro-
cellulose when put up in this form is about the length of
the chamber in the gun or long enough to about fill the
38 EXPLOSIVES AND DETONATORS
cartridge case. Another way in which nitroglycerine
smokeless powder is put up is the slab form shown at B.
In cartridges used by the French government, this slab is
0.0195 inch thick, i/ inch wide, and about from 5 to 6 inches
long. This form of smokeless powder is also used by the
Italian government. In the United States Army service,
the nitrocellulose powder is put up in the form of cylindri-
cal grains, as shown at C and D, which are provided with
seven longitudinal perforations, one central and the other
six equally distributed midway between the center of the
grain and its circumference. A uniform thickness of web
is thus obtained. The length and diameter of the grain
vary in powders for different guns, the size increasing with
the caliber of the gun. The length is unimportant, the web
between the perforations being the factor that receives first
attention. For the 3-inch rifle, the grain has a length of
about % inch and a diameter of 0.195 inch, as shown at D.
For the 12-inch rifle, the length is 1% inch and the diame-
ter % inch, as shown at C. For smaller guns, the grains
are in the form of thin flat squares, as shown at E. When
used in howitzers or mortars, smokeless powder is put up
sometimes in the form of tubes, solid and tubular rods, flat
disks, and rolled sheets.
High-explosives or Shell Fillers. High-explosives, which
are generally termed "shell fillers," are known by various
trade-names; such as emmensite, lyddite, melenite, maxim-
ite, nitrobenzole, nitronaphthaline, shimose, trinitroto-
luol, etc. The base of such explosives as emmensite, max-
imite, lyddite, melenite and shimose is picric acid, which is
secured from coal tar subjected to fractional distillation.
The liquid that comes off when this is raised to a tempera-
ture of 302 degrees F. (150 degrees C.) is called "light"
oil, and when these light oils have been again distilled, the
next fraction or "middle" oil is phenol or carbolic acid ; this
substance when nitrated gives off picric acid, or, as it is
sometimes called, trinitrophenol. As a shell filler, this ex-
plosive may be pressed into the explosive cavity or melted
and poured in. It forms an unstable metallic salt when
coming in contact with the body of the shell, and, conse-
EXPLOSIVES AND DETONATORS 39
quently, when assembling or when pouring the melted acid
in the shell, it is necessary to first coat the cavity thoroughly
with a non-metallic paint. Picric acid is the basis of many
of the foreign shell fillers. The difference in composition
of these various explosives usually consists in the addition
of an ingredient (camphor, nitronaphthaline, trinitroto-
luene, etc.) which are introduced to reduce the melting
point.
At present, the most popular or generally used shell
filler is T. N. T. (trinitrotoluol). Although the explosive
force of trinitrotoluol is somewhat less than that of picric
acid, the pressure of the latter being about 135,820 pounds
per square inch, as against 119,000 pounds for trinitroto-
luol, its advantages more than compensate for the differ-
ence. Trinitrotoluol is obtained by the nitration of toluene
obtained from crude benzol distilled from coal tar and
washed out from coal gas. The crude benzol contains
roughly :
Constituent 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 not less than
0.868 nor more than 0.870, at about 59 degrees F. (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 356 degrees F. (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
force, giving off a black smoke. Shells containing this ex-
plosive first used on the Western battlefront were given
such names as "coal-boxes," "Jack Johnson," "Black
Maria's," etc., by the Allies.
40 FULMINATES AND CHLORATES
In the United States service, picric acid, explosive "D,"
and trinitrotoluol are used as shell fillers. High-explosive
shells containing explosive "D" with a small charge of picric
acid surrounding the detonator are used, and in high-explo-
sive shrapnel, trinitrotoluol is used as a matrix. Trinitro-
toluol may also be detonated with a fulminate-of-mercury
detonator augmented by a small amount of trinitrotoluol in
loose crystals.
The Russians and Austrians use a high-explosive known
as ammonal, in which from 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 must be made up in air-tight car-
tridges. 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.
Fulminates and Chlorates. The action of fulminates is
more powerful than either the low- or high-explosives de-
scribed. 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 the cartridge case, and
in fuses, either of the plain percussion or 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 pro-
duced 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 fric-
tion, it is usually kept in water or alcohol until needed.
A common mixture of fulminate of mercury for use in
primers contains the following ingredients :
Ingredients Per Cent
Fulminate of Mercury 50
Chlorate of Potassium 20
Glass (ground) 30
FULMINATES AND CHLORATES 41
The ground glass must be sifted through a sieve having
100 meshes to the linear inch. To the mixture given is added
0.25 per cent of tragacanth gum and a trace of gum arabic.
This composition is placed in the primer while moist; after
compression, the primer cap is dried for ten days at a tem-
perature of 88 degrees F. (about 31 degrees C.), and for
twelve days at 111 degrees F. (about 44 degrees C.). Then
the exterior surface of the parchment covering the mixture
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
resin. The varnished primers are dried at a room tempera-
ture for five or six days.
In primers used in British, American, and some of the
foreign cartridge cases, the fulminate-of -mercury detonator
is replaced by chlorate of potassium. The resulting com-
position is less dangerous to handle than when ful-
minate of mercury is used, and also has much less erosive
effect on the bore of the gun.
CHAPTER III
FORGING HIGH-EXPLOSIVE SHELLS
AT present, the preliminary stages in the manufacture of
high-explosive shell forgings are carried on in one of two
ways : The first is to use hot-drawn bar stock cut up into
billets of the required length in cutting-off or shearing
machines; the second is to cast billets, varying in length
and diameter, depending on the size of the shell. These bil-
lets are then cut up into blanks of the required lengths for
forging.
In one of the prominent Canadian plants engaged in this
work, billets for British 4.5 high-explosive shells are cast
in ingot molds to 33 inches in length by 4 15/16 inches
in diameter. Following the casting, the billets are
thrown down into the sand and allowed to cool off.
Next, the billets are cut into sections 9-^ inches long,
the bar being partly severed at the required points and
then taken out of the lathe and broken. The teats are fin-
ally cut off on a planer, leaving the blanks in a suitable con-
dition for forging. When the forgings are made from
bar stock, cut off from hot-rolled bars, the high-power cut-
ting-off machine is generally used.
Forging British 4.5 High-explosive Shell Blanks. Sev-
eral methods have been used in the Canadian plants in
forging high-explosive shell blanks. One prominent con-
cern, in the early stages of this work, adopted the method
shown in Fig. 18 for forging 4.5 high-explosive shell blanks.
A blank 4 13/16 inches in diameter by 9 inches long was
heated in a furnace to 1950 degrees F. (about 1070 degrees
.C.) for about 45 minutes and then taken out and dropped
into the die a shown at A, Fig. 18. One operator then
quickly placed the guide b over the die and put in the punch
42
FORGING SHELLS
43
Fig. 18. Three-operation Method of making 4.5 British
High- explosive Shell Forgings
44
FORGING SHELLS
c, which a steam hammer started into the billet. When
the punch had been driven in far enough to get a good
start, it was removed, cooled in water, the guide b removed,
the punch replaced, and three or four blows delivered, fin-
ishing the billet as shown at B. The billet was again heated
to the correct temperature, placed in the die, as shown at C,
and drawn up to the shape shown at D by one stroke of a
hydraulic press of 500 tons' capacity. A final forging or
drawing operation was then accomplished by forcing the
Machinery
Fig. 19. One-operation Method of making 4.5 British High-
explosive Shell Forgings
forging through two dies that are 5 1/16 and 4 15/16 inches
in diameter, respectively, as shown at E and F. The forg-
ing as completed was 4% inches in diameter, by 12% inches
long, with a base 11/2 inch thick. After the forgings
were removed from the die, they were allowed to cool, after
which they were inspected.
Later Method of Forging British Shell Blanks. The
method just described has been improved by the concern
using it; the new method is illustrated in Figs. 19 and 20.
In Fig. 20 is shown the 350-ton hydraulic press used to
FORGING SHELLS
45
complete the forging in one "shot." The billet, as shown in
Fig. 19, is 4.8 inches in diameter and 91/2 inches long. This
is cut off from a cast billet and placed in a furnace heated
by fuel oil until it reaches a temperature of about from 1900
to 1950 degrees F. (about from 1040 to 1070 degrees C.) . It
Fig. 20.
Forging British 4.5 High-explosive Shells in One
Operation
is then pulled out by a long bar with a bent end, dropped on
to a sheet-iron slide, and carried over near the hydraulic
press. Here it is quickly picked up by one of the operators
and placed on a block, where all the excessive scale is re-
moved by means of a scoop. It is then dropped into the
46 FORGING SHELLS
die and the press operated. In this particular case, no
bushing or guide is used to center the punch, which is al-
lowed to descend freely into the heated billet, extruding
it around the punch. The punch and die are kept lubri-
cated with a mixture of graphite and oil and are also cooled
by a stream of water after each billet has been pierced.
In this operation, the forging is drawn out in one "shot"
from 9V to 13% inches in length; sometimes it even ex-
ceeds 14 inches. The shape of the die and the size and
shape of the finished forging are shown at B, Fig. 19. The
production on this operation is 220 in eight hours, and four
Fig. 21. Cutting off Blanks for Russian 3-inch High-
explosive Shell Forgings in a Shearing Press
men are required, three to attend to the press and one to the
furnace.
Forging Russian 3-inch High-explosive Shell Blanks. -
A very complete and interesting forging equipment is used
by the Laconia Car Co., Laconia, N. H., for turning out
3-inch Russian shrapnel forgings at the rate of 3000 per
day. In this plant, the bulldozer is used for performing
both the piercing and drawing operations on the forgings.
Russian high-explosive shell forgings are made from steel
containing 50-point carbon and are also high in manganese.
Great difficulty has been experienced in cutting these bars
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48 FORGING SHELLS
After cutting off, the billets are placed in a furnace of the
type shown in Fig. 22, which has been built especially for
this work by this company; here the blanks are heated to
2250 degrees F. (about 1230 degrees C.). These furnaces
are of the open-hearth down-draft type, built to the dimen-
sions given in the illustration. The heating space is 18
inches at the highest point of the arc, and 3 feet wide by
5 feet 6 inches long. Each furnace is provided with two
double burners, and i/2-pound air pressure from a Sturte-
vant fan is sufficient to operate them. In maintaining a
temperature of 2250 degrees F., only 9 gallons of crude oil
Fig. 23. Arrangement of Dies and Punches on Williams &
White Bulldozer for forging Russian High-explosive Shells
is consumed per hour by each furnace. With these fur-
naces, a temperature of 2850 degrees F. (about 1570 de-
grees C.) can be obtained without trouble, but the tempera-
ture required for this work seldom exceeds 2300 degrees
F. (about 1260 degrees C.).
Forging Machine. The forging is done on a Williams &
White size 9-U bulldozer, as shown in Fig. 23. This ma-
chine is capable of making six strokes per minute and a
forging is completed in two strokes ; the piercing and draw-
ing operations are carried on at the same time. The pierc-
ing punches and dies shape the piece, as shown at B, Fig.
FORGING SHELLS
49
24, whereas the drawing punches and dies complete the
forging as shown at C. The piercing and drawing dies
are held in a special holder fastened to the bed, whereas
the punches are held on the cross-head. The two outer
punches at each side, A, B, C, and D are the drawing
punches, and the four inner ones E, G, H, and I are for
piercing. There are seven men in the forging team for
each machine: One attends to the furnace, one removes
the forgings from the furnace, and one starts and stops the
bulldozer and looks after the machine; on each side of the
machine there are two tool-men and two forgers.
2 TMDS. PER INCH R.H.
Fig. 24. Russian 3-inch High-explosive Shell from the Blank
to the Finished Shell
The method of operation is as follows: The forge-man
gets the hot billet from the furnace-man and puts it in one
of the two piercing dies on his side of the machine ; one blow
partly forms it. He then passes it on to one of the two
drawing punches at his side, the tool-man swinging the
punch up to permit the' forging to be removed and at the
same time greases the punch. The object of having two
piercing and two drawing punches is to allow one to cool
while the other is being used, the two sides of the machine
being used alternately.
50
FORGING SHELLS
Fig. 23 shows clearly how the punches and dies are
held. The piercing punches are shorter than the drawing
punches and pass through the strippers K, which remove
the pierced forging from the punch, as the forging is not
forced through the die when being pierced. The strippers
are operated by the V-shaped members /, which come be-
tween them and close them in on the punch.
The piercing punches are made from special vanadium
steel, and 5000 forgings are made before the punches are
worn out. The drawing punches are also made from vana-
Fig. 25. Method of Forging Large-caliber High-explosive Shells
dium steel and turn out about 3000 blanks before giving
out. For the dies, white cast iron is used, and 4000 blanks
is the limit obtained from one die. The drawing dies are
made of chilled cast iron and last from 1800 to 2000 forg-
ings. The forgings are not annealed, but are allowed to
cool slowly in sand. One team of men and one machine will
produce 500 forgings in eight hours without any trouble.
FORGING SHELLS
51
Forging Large-caliber Shell Blanks. At present, there
are two principal methods of making large high-explosive
shell blanks. One of these does not differ materially from
that used in the production of forgings for medium-caliber
shells. In the large-caliber shells, the hole in the nose, when
the shell carries a nose fuse, is small in proportion to that
used in the small-caliber forgings. Consequently, a greater
amount of metal is turned in at the nose.
One method of making these shells is shown in Fig. 25.
C Machinery
Fig. 26. Diagram illustrating Method of Forging Armor-piercing
Shells
The preliminary stages in the process, shown by the dia-
gram at A, B, C, D, and E, are the same as for making an
ordinary forging. For instance, the billet is pierced, as
shown at A, B, and C, by being forced over punch d by
punch c acting through die a. The frame carrying die-
holder b then rises, and stripper plate e removes the pierced
forging from the punch, as shown at D. The next step
consists in drawing the pierced forging through dies, as
shown at E. The forging is then heated on the nose end,
52 FORGING SHELLS
taken to another press and dropped into a die, as illustrated
at F. The nosing-in punch then descends, as shown at G,
and closes in the open end of the forging to the shape
shown at H. Further operations consist in drilling out the
nose for the fuse, and threading it, etc., for the reception of
the fuse. In this class of forging, no machining whatever
is done in the cavity of the shell.
A method of making large-caliber shell f orgings that are
open both on the nose and the base ends is to use seamless
drawn tubing. The operation consists in cutting a piece
of tubing to the required length, heating one end, and plac-
ing the tubing in a hydraulic press, where, by means of a
properly shaped die and punch, the base end is upset in
toward the center. The forging is then heated on the
opposite end, placed in another press, and nosed-in in a
manner similar to that shown at G, Fig. 25. This method
of making large forgings has the advantage of saving con-
siderable material, both in the preliminary stages and in
the final machining operations.
Forging Armor-piercing Shells. Armor-piercing shells
are always made with a solid nose, as this type of shell is
used for piercing hardened armor, which calls for great
strength in the nose. One method of making armor-pierc-
ing shells, which is also applicable to the production of the
type of high-explosive shell used by the United States gov-
ernment, is shown in Fig. 26. This method does not differ
in principle from that shown in Fig. 19, except that the shell
is forged with the nose instead of the base down. Usually,
the punch is not relied upon to center in the billet accu-
rately, so a centering bushing is used. The bushing is in-
serted in the top of the die, the punch is allowed to descend
for a short distance into the heated billet and is then raised ;
the bushing is then removed and the punch again advanced.
When making a forging in the manner shown in Fig. 26,
it is usually necessary to eject the forging and make it fol-
low the punch, from which it is removed by a stripper as the
punch rises.
CHAPTER IV
MACHINING BRITISH 18-POUND SHELLS
A VARIETY of methods are used in machining the British
18-pound (3.29-inch) high-explosive shell shown in Fig. 27.
In the greater number of cases, however, the shell is ma-
chined from bar stock. One of the two principal methods
used in machining from bar stock, outlined in Table I, con-
sists in cutting up bars of hot-drawn stock into billet
lengths, which are then drilled and reamed, and afterwards
turned, etc. The other, while similar in the final opera-
tions, starts with turning. A bar generally sixteen feet
i^ > |^ . ^
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L0.73 L0.880
Machinery
Fig. 27. British 18-pound High-explosive Shell
long is centered on both ends, then put in the lathe and
turned down to approximately the finished size. After this,
it is cut up into shell lengths, drilled, reamed, threaded, etc.
Cutting off 18-pound Shell Blanks. Many methods are
used for cutting off shell blanks ; usually, however, several
blanks are cut off at one time. The Earle Gear & Machine
Co. has devised a fixture for the Lea-Simplex cold saw by
means of which nine bars can be cut off at one setting. The
average cutting time for nine bars is nine minutes, and the
production on 314 -inch bars is about sixty per hour.
53
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MACHINING BRITISH SHELLS
55
Drilling and Reaming. After cutting off, the first opera-
tion, rough-drilling, is usually performed in a high-power
drilling machine, as shown in Fig. 28. The shell blank is
held in a special fixture, shown in Fig. 29, consisting of two
jaws operated by left- and right-hand screws by means of
handwheel A. The top of the fixture is of yoke form and
Fig. 28. Baker High-power Drilling Machine at Work on British
18-pound High-explosive Shells
carries the drill-guiding bushing B. In this particular case,
the drilling is done with a "Hercules" 1 13/16-inch drill,
rotated at 115 R. P. M. and fed down into the work at a
feed of 0.017 inch per revolution of the drill. The hole
drilled is 8% inches deep, and the production is nine per
56
MACHINING BRITISH SHELLS
hour. To start the drill central with the blank, a bushing
is slipped into the top of the jig, but when the drill has
once started properly this is removed. The second opera-
tion consists in rounding the bottom, that is, removing the
vee left by the end of the drill. This is done with a coun-
terboring tool rotated at 115 R. P. M. and fed down by
hand. The machine used is a Baker high-power drilling
Machinery
Fig. 29.
Fixture used in Holding 18-pound Shell Blanks when
Drilling
machine and the production is thirty per hour. The third
operation consists in reaming the hole to 1.885 inch in
diameter with a reamer rotated at 115 R. P. M. and fed at
the rate of 0.032 inch per revolution to 8 15/16 inches deep ;
the production is twelve per hour.
Turning Band Groove, Waving, etc. The fourth opera-
tion is performed on a No. 2-A Warner & Swasey turret
MACHINING BRITISH SHELLS
57
lathe in the order shown by the diagram, Fig. 30. This
consists first in rough-turning the external diameter with a
box-tool A for a distance of about 6% inches from the base
end and removing % inch from the diameter at a feed of
0.041 inch per revolution of the work; second, boring the
gas-plug recess, facing the end, and turning and forming
the radius with tool B; third, rough-forming the band
groove with tool C; fourth, finish-facing the plug recess
and end with tool D; fifth, forming waves in the band
2ND OPERATION
BORE, FACE, TURN AND
FORM RADIUS
/ OPERATION
ROUGH TURN
3RD OPERATION
FORM BAND GROOVE
4TH OPERATION
FINISH FACE RECESS
AND END
TH OPERATION
FINISH BORE,
COUNTERBORE,
AND CHAMFER
5TH OPERATION
FORM WAVES IN
BAND GROOVE
7TH OPERATION
UNDERCUT
BAND GROOVE
Machinery
Fig. 30.
Diagram showing Set-up for performing External Turn-
ing, Facing and Waving Operations
groove from the cross-slide with tool F; sixth, finish-boring,
counterboring, and chamfering the plug recess with tool G;
seventh, under-cutting the band groove with tool H. The
waving is done from the cross-slide and at the same time the
work is supported by a roller support from the turret. For
the finishing cuts, the work is rotated at 187 R. P. M., and
the production is from six and one-half to seven per hour.
Rough-turning, Facing, etc. The fifth operation con-
sists in rough-turning the nose in a Reed-Prentice 20-inch
58
MACHINING BRITISH SHELLS
engine lathe, as shown in Fig. 31, with a single tool operat-
ing at a feed of 0.071 inch per revolution, and with the
work revolving at 56 R. P. M. The shell is held in a special
draw-in collet A that is supported by a steadyrest, as shown.
Three cuts are required to finish the nose of the shell to
form, the tool being controlled in its movement by a cam lo-
cated at the rear of the machine. The production is from
twelve to fourteen per hour.
The sixth operation is performed on a No. 2-A Warner &
Swasey turret lathe, as shown in Fig. 32. In this set-up
the shell is rough-faced to length and the clearance angle
Fig. 31. Rough-turning Nose in an Engine Lathe
cut on the nose. The recess is then cut at the bottom of
the thread with recessing tool A and the hole reamed for
threading to 1.906 inch in diameter, 1.2 inch deep, with tool
B. A light cut is taken across the radius on the nose with
tool C which carries a roller pilot and is operated from the
cross-slide. The work is rotated at 78 R. P. M. for the pro-
filing or the radius cut at a feed of 0.058 inch per revolu-
tion. The feed is reduced to 0.028 inch per revolution for
reaming. The production is fifteen to seventeen per hour.
Finish-turning. The seventh operation consists in fin-
ish-turning from the band groove to the nose on an F. E.
MACHINING BRITISH SHELLS
59
Reed 18-inch engine lathe, as shown in Fig. 33. Here the
cross-feed screw has been removed and the movement of
the cross-slide is controlled by a former at the rear. The
shell is held at the closed end by a two-jaw chuck, and lo-
ng. 32. Performing Sixth Operation on a 2-A Warner & Swasey
Turret Lathe
Fig. 33. Finish-turning External Diameter on an Engine Lathe
cated by a stop-screw A; a plug is screwed into the open end
and is supported on the tailstock center. The work is ro-
tated at 100 R. P. M. and the feed is 3/64 inch per revolu-
60
MACHINING BRITISH SHELLS
tion. One man runs two machines and the production is
twelve to fifteen per hour from each machine.
Counterboring, Making Screw Holes, etc. The eighth
operation is to counterbore and drill the grub-screw hole A,
Fig. 27, in the nose of the shell for fastening the fuse in
place. The ninth operation on the shell consists in tapping
the screw hole with a Peter Bros, tap chuck held in a Barnes
drill. It requires two taps to finish this hole and they are
operated at 40 R. P. M. ; the production is forty per hour.
The tenth operation is to face the recess in the cavity in
the base end of the shell where the gas plug is to be in-
serted. This is performed in a Fay & Scott 16-inch engine
Fig. 34. Threading Nose and Base Ends of Shell in Holden- Morgan
Special Thread Milling Machines
lathe, and one cut is taken with a tool held in a special
holder. The tool is started at the outside of the recess and
works in toward the center. The work is rotated at 180
R. P. M. and the feed is 1/32 inch per revolution; the pro-
duction is forty per hour.
Threading Nose and Base Ends. The eleventh opera-
tion consists in threading the nose of the shell in a Holden-
Morgan thread milling machine, as shown in Fig. 34. A
hob similar in construction to that described in connection
with Fig. 35 is used for cutting the thread, and one revolu-
tion of the work completes the thread, which requires 1.10
minute. The production is twenty per hour from each ma-
MACHINING BRITISH SHELLS
61
chine, one operator attending to two machines. The twelfth
operation consists in recessing and threading the base end
of the shell in a Holden-Morgan threading machine of the
same type as those shown in Fig. 34. Here one man also
runs two machines, one being set up for recessing and the
other for threading. The production is 130 in ten hours
from the two machines. The thirteenth operation consists
in washing the shells in hot soda water, after which they
are inspected.
Machining the Gas Plug. Before any other operations
are performed on the shell, the gas plug B, Fig. 27, is made
Fig. 35. Machining Gas Plugs on Holden-Morgan Special Plug
Machine
from a forging and is faced, turned, and threaded on the
Holden-Morgan special plug milling and threading machine
shown in Fig. 35. The plug is held by the tail in a special
draw-in chuck. The first operation is to rough-turn and
face the end of the plug, two cuts being taken. The tools
used are located one behind the other in a tool-holder A
that is fastened to the front of the cross-slide operated by
the handwheel B. On the rear of the same slide is a special
holder C that carries the threading tool. This consists of a
hob built up of a series of concentric disks provided with
cutting teeth and held on a special arbor driven by a sep-
62
MACHINING BRITISH SHELLS
arate belt D. To cut the thread, lever E is pulled down,
withdrawing a stop which allows the spindle to feed back
into the housing. The spindle-driving mechanism is then
shifted to slow speed, and the spindle moves back at the
required pitch slightly over one complete revolution of the
work (which takes forty seconds) finishing the thread.
The work is rotated at 200 R. P. M. for turning and facing,
and the production is twenty per hour.
Fig. 36. Riveting in the Gas Plug in a "High-Speed" Hammer
Final Machining. The fourteenth operation consists in
screwing in the base plug, which is first coated with red
lead. Two men are employed for this operation, one in-
serting the plug and the other screwing it in with a wrench.
The production is thirty per hour. The fifteenth operation
consists in hogging off the projection on the base plug in
MACHINING BRITISH SHELLS
63
a Jenckes lathe. First, a facing cut is taken along the plug,
then the teat is cut off, and finally a finishing cut is taken.
The production is thirty-two per hour, and the lathe is op-
erated at 180 R. P. M., hand feed being used.
The sixteenth operation consists in riveting in the gas
plug with a "High-Speed" hammer operating at 500 blows
per minute, as shown in Fig. 36. The shell is held on an
Fig. 37. Varnishing Interior of High-explosive Shells
arbor and is spun around by the operator as the hammer
descends. The production is 120 per hour. The seven-
teenth operation consists in facing the base in a Jenckes
machine, one cut being taken at a spindle speed of 180 R. P.
M. and 1/32 inch feed per revolution of the work. The
depth of cut is 3/32 inch. The eighteenth operation is cut-
64
MACHINING BRITISH SHELLS
ting the air grooves in the waves in the band groove. This
is accomplished in a Brown-Boggs inclinable press which
carries a fixture in which the shell is located. The cuts are
made with a punch, shaped like a cold-chisel, held in the
ram of the press, and the production is 240 per hour. In
the nineteenth operation, the copper band is pressed into
the band groove in a Goldie & McCulloch hydraulic press of
the six-cylinder type. Three squeezes are required to com-
press this band, and the production is forty per hour.
Fig. 38. Stamping in a Holden- Morgan Rotary Stamping Machine
For the twentieth operation, the shell is brought back to
a Warner & Swasey brass-working lathe, where the copper
band is turned to shape. The work is rotated at 120 R.
P. M. and roughing and finishing cuts are taken. The
roughing cut is taken from the front slide and the finishing
cut from the rear. The shell is supported by means of a
steadyrest. The production is forty per hour.
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66 MACHINING BRITISH SHELLS
temperature for eight hours. The shells are allowed to re-
main in the furnace for this time and then are taken out
and allowed to cool off in the air. The twenty-third opera-
tion is cleaning the nose of the shell with a rag and gasoline.
The shells are then ready for inspection, after which the
plug is screwed into the nose end.
The twenty-fourth operation consists in stamping in the
Holden-Morgan machine shown in Fig. 38. The stamp A
is oscillated by an eccentric and crank movement, and when
Fig. 39. Turning Long Bars from which Billets for High-explosive
Shells are subsequently cut
the stamp is brought down in contact with the work by
operating handwheel B the shell is rotated by it. The pro-
duction in this operation is sixty per hour. The twenty-
fifth operation is the final manufacturing and government
inspection ; 240 completed shells represent eight hours' work
in this plant.
Alternative Method of Machining British 18-pound Shells.
A method that is not as widely practiced as that
just described is outlined in Table II. By it, hot-drawn
MACHINING BRITISH SHELLS 67
steel bars 3!/2 inches in diameter by 16 feet in length are
centered in both ends, by first scribing two diametral lines
across the ends of the bar and then drilling the center holes
with a portable drill. The bars are next set up on centers
on an engine lathe and straightened with a jack until they
run fairly true. One end of the bar is then stepped down
to the required diameter for a length of approximately 18
inches; the purpose of this is to form a bearing for the
steadyrest, which is used during the turning operation,
and also to provide a starting point for the special turning
head employed. The bars are turned down to a diameter
Fig. 40. Cutting Turned Bars to Shell Lengths in a Newton
Cold Sawing Machine
of 3.285 inches 0.005 inch, and for this purpose a special
traveling head, as shown in Fig. 39, is employed. This
head carries five tools, three next to the chuck and two on
the opposite side of the supporting bushing. The first two
cutters are progressive roughing cutters, the third is a
"smoothing" cutter, and the two cutters on the right-hand
side of the supporting bushing take finishing cuts ; the depth
of the cut taken by the last finishing tool is very light. Ac-
curacy for diameter is determined by a snap gage and a ring
gage; the snap gage is used to make sure that the bar is
not turned under size, whereas the ring gage follows along
68
MACHINING BRITISH SHELLS
Fig. 41.
Machining Hole and Nose of Shell Blank in Barnes
Drilling Machine
the bar after the turning head. Should it happen that the
last tool is cutting too large, the operator takes a file and
touches the high spots until the ring gage will pass.
Sawing Turned Bars to Billet Lengths. Two Newton
MACHINING BRITISH SHELLS 69
machines equipped with Huther inserted-tooth saw blades
are used for cutting up the turned bars into shell blanks
9% inches in length. These machines, as shown in Fig. 40,
hold four bars at a time, and are equipped with traversing
work-holding fixtures that move the stock along after each
successive cut has been completed, a stop being employed
to control the length of the blanks. The work is held in
the fixture by a special arrangement of clamps, which are
Fig. 42. Close View of Fixture shown in Fig. 41, illustrating
Method of applying Tools to Work in an Inverted Position
operated by compressed-air cylinders working in conjunc-
tion with toggle-joints. In order to facilitate loading the
bars into the work-holding fixture, an auxiliary rack is pro-
vided in which four bars are placed before the four bars in
the work-h<flding fixture have been completely cut. When
the final blanks have been cut from the bars, the work-
holding fixture is moved back to the starting point and the
70 MACHINING BRITISH SHELLS
auxiliary rack which is pivoted to the base that supports
the traveling work-holding fixture is swung up by means
of a crane hoist. This brings the next four bars into posi-
tion in the rack ready to be clamped.
The design of the traveling work-holding fixture is such
that the bars cannot be completely cut up into blanks, the
crop end of each bar having sufficient material for three
shell blanks. These crop ends are cut up on another cold
saw; one of the blanks produced in this way is already
turned to size, while the other two blanks are cut from the
rough end of the bar which was not reached by the special
turning head shown in Fig. 39. These two rough crop ends
are turned down to the required diameter on an engine lathe.
Drilling, Reaming, and Turning Nose. The method used
for drilling, reaming, and forming the nose of the shell differs
greatly from that just described. The development of fixtures
for performing this work on the upright drilling machine
is unusual, so this method has largely overcome the great
difficulty experienced in securing early deliveries on all
forms of lathes for machining shells. Besides, by the in-
verted-tool method, chip trouble is largely overcome. The
equipment used consists of a battery of eight, self -oiling, 22-
inch, all-geared, drilling and tapping machines built by the
Barnes Drill Co., and much of the credit for the development
of this method of machining shells is due to the designers
employed by this concern. Figs. 41 and 42 show one of
these machines equipped for shell work. These show that
the shell to be machined is held by a chuck on the drill spin-
dle, whereas, the tools that perform the drilling, reaming and
nose-forming operations are carried by a rotary fixture B
supported on the table of the machine. The fixture consists
of a baseplate and rotating table upon which the tool-
holders are mounted. The proper indexing of the various
tools is provided for by means of a taper pin in the base of
the fixture engaging corresponding holes in the rotating ta-
ble which is rigidly retained by a clamp. The sequence of
operations is as follows :
First Operation: Spot-drill and rough-form nose with
tools held in holder C. For this operation the spindle ro-
MACHINING BRITISH SHELLS 71
tates at 92 R. P. M. with a down feed of 0.013 inch per
revolution. The drilling is done by a short twist drill, and
the rough-forming of the nose by three turning tools which
are stepped in so that they cut to different depths, leaving
an irregular surface that is finished in a subsequent opera-
tion. The shell is supported by a bronze-lined bushing
so that the work is adequately supported while being
machined.
Second Operation: Drill hole in shell to required depth
with a drill D 1 13/16 inch in diameter. For this opera-
tion the spindle is rotated at 145 R. P. M. and at a feed of
0.013 inch per revolution.
Third Operation: Rough-ream the hole with reamer E,
which is formed at the end to finish the bottom of the cavity
to the required shape. For reaming, the spindle is oper-
ated at 37 R. P. M. with a down feed of 0.093 inch per
revolution. When the reamer reaches the pointed end of
the hole as left by the twist drill, the power feed is disen-
gaged and the spindle fed down by hand until the positive
stop is reached.
Fourth Operation: Finish-form nose with form-cutter
located in holder F, which is bronze-lined. The spindle is
rotated at 45 R. P. M. and fed down by hand.
Fifth Operation: Cut step and bevel on nose of shell.
The work is supported by a bronze-lined tool-holder G, and
the machine is operated at the same speed and feed as for
the fourth operation. The bevel on the inside of the nose
is machined by a double-ended cutter of the proper form,
which is supported at the center by a toolpost bolted to the
base of the fixture. The step is formed by two forming
tools carried by toolposts bolted to the base of the fixture.
Sixth Operation: Finish-ream with reamer H. This
operation must be performed with great care, as the speci-
fications require that when an electric light is dropped into
the hole, the surface will show a uniform polish in all places.
This operation is performed with the spindle rotating at
37 R. P. M. with a down feed of 0.093 inch per revolution.
By holding the shell in a fixture on the drill spindle, ad-
vantage is taken of the inverted principle which allows the
72 MACHINING BRITISH SHELLS
chips to clear themselves more freely than would otherwise
be the case. All the drilling and reaming tools used are of
the oil-tube type and are supplied with forced lubrication.
The chuck in which the work is held is arranged with three
serrated eccentric jaws mounted on a rotating ring. To
Fig. 43. Drilling and tapping Hole for Fuse Fixing Screw
clamp the work in the chuck, the ring that carries the jaws
is turned back against spring tension to allow the work
to be pushed up into place. The ring is then released and
snaps back to give the jaws a preliminary grip on the shell.
When the machining operation is commenced, the resistance
of the work to the cutting action of the tools causes a fur-
MACHINING BRITISH SHELLS 73
ther rotation of the ring on which the chuck jaws are car-
ried, with the result that the jaws rock in on their eccen-
tric pivots to secure a firmer grip on the work. After the
machining operations have been completed, the work is re-
moved from the chuck by a wrench which is slipped over the
end of one of the jaws, and pressure is applied to rotate the
chuck ring in the opposite direction from that necessary to
tighten the jaws.
Drilling and Tapping for Fixing Screw. The operation
of drilling and tapping the hole in the nose for the fuse
fixing screw is accomplished in a two-spindle drilling ma-
Fig. 44. Milling Threads in Nose In a Special Lees-Bradner Thread Milling
Machine
chine as shown in Fig. 43. The first spindle is used for
counterboring and drilling. After the hole has been started
with drill A, it is removed and the smaller drill B inserted.
The fixture carrying the work is now moved over to the
second spindle of the machine and the hole threaded with
tap C, which is held in an Errington chuck. For this oper-
ation, of course, it is necessary to remove the drill guide
bushing.
Milling Threads in Nose. In the special Lees-Bradner
thread milling machine shown in Fig. 44, the shell is held
in an air chuck with the open end out. The threading is
done with a multiple type cutter A, of a length sufficient
74 MACHINING BRITISH SHELLS
to completely cover the length of the part to be threaded
and which is rotated by a separate belt B. The cutter-slide
is fed toward the head of the machine, and the work ro-
tated at the same time so as to cut a thread of the correct
pitch. This is controlled through a change-gear system lo-
cated at the left-hand end of the machine.
Turning, Under-cutting, and Waving Band Groove.
Before the machining of the band groove, a center hole is
drilled in the base end of the shell. After this operation,
the shells go to the preliminary inspection department
Fig. 45. Turning, under-cutting and waving Rifling Band Groove
where the thread in the nose is tested with a thread plug
gage. A driving center is then screwed into the nose of
the shells, and they are returned to the machining depart-
ment. The band groove is machined as shown in Fig. 45.
The roughing out of the band groove is done by means of a
formed tool held on the rear cross-slide, which leaves suffi-
cient stock to form the waves. The next step is to under-cut
the sides of the band groove by two tools held in the holder
B; when one tool is in action, the other clears the end of the
shell. The machining of the waves is performed by a tool C
held in the holder D. This holder forms part of a slide
MACHINING BRITISH SHELLS
75
which carries a roller that engages with cam E. Spring F
keeps the roll in contact with the cam, so that, when the lat-
ter rotates, an oscillating movement is imparted to holder D.
Preliminary Inspection. After the band seats have been
machined, the driving centers are removed from the nose
of the shells and the latter are subjected to a preliminary
inspection. This consists in weighing in order to determine
the amount of stock that must be removed from the base to
bring the shells to standard weight. The normal weight of
the finished shell is 14 pounds, 13.15 ounces, and a tolerance
Fig. 46. Facing-off Base End and machining Gas Plug Seat
of 1 ounce is allowed. Experiments have established the
fact that each ounce of weight on the shell is equivalent to
0.026 inch in length at the base, so that, by removing the
metal on this basis, the weight of the shell may be reduced
to normal. The inspector who weighs the shells has a chart
before him on which the various weights of shells are type-
written, together with the corresponding amount of metal,
in thousandths of an inch, that must be removed from the
base in order to bring the shell to normal weight. At this
stage, the shells also have the heat number of the steel bar
stamped on the base; as the metal is to be removed from
76 MACHINING BRITISH SHELLS
the base, the inspector transfers this heat number to the
side of the shell. After he has weighed the shell and de-
termined the amount of metal that must be removed, he
marks the number of thousandths inch to be removed on the
side of the shell with blue chalk ; the shells are then sent on
to the lathe department where the correction for weight is
made while the hole is being bored to receive the gas plug.
Fig. 47. Fixture used for driving in Gas Plugs
Facing Base End of Shell. The engine lathe used for
facing the base end is equipped with a special micrometer
attachment which enables quick settings to be made. This
attachment, as shown in Fig. 46, consists of a bracket
bolted to the lathe bed, on which the spindle of a micrometer
A is supported. The connection between the micrometer
and the supporting bracket is cushioned by a spring, so
that, when the lathe carriage is brought up against the mi-
MACHINING BRITISH SHELLS 77
crometer spindle, the spring will take up the strain and pre-
vent the instrument from being damaged.
In operation, the shell is gripped in a Hannifin air chuck
and the facing tool brought into contact with the base of the
shell. The micrometer spindle is then screwed up against
the end of the lathe carriage and a reading taken, after
which the spindle is backed away the necessary number of
thousandths inch that the inspector has found must be re-
moved from the shell to bring it to normal weight. The
carriage is moved out until the tool clears the work, then
moved to the left until it makes contact with the micrometer
spindle. After this setting, the cross-slide is fed in until
the tool passes beyond the circumference of the hole subse-
quently to be bored. The cross-slide is then backed away
from the work and the boring tool B held in the tailstock
spindle is fed in to bore the hole for the plug. The turret
toolpost is then revolved to bring the reaming tool into
position to take a finish cut on the side and bottom of the
hole. The tool used for this purpose has a double cutting
edge with the edges located at right angles to each other.
After the finish cut has been taken, the turret toolpost is
again rotated to bring the under-cutting tool into the work-
ing position, and the under-cut is made.
Gas Plugs. The shells now go to another Lees-Bradner
thread milling machine of the type shown in Fig. 44, where
the threads for the gas plugs are milled. These plugs are
drop-forgings provided with a triangular head to fit the
wrench used in screwing them into the shells. Before being
screwed into place, the disks are painted with red lead on
the bottom and threads and screwed loosely into the shells.
The work then goes to an upright drilling machine, Fig. 47,
equipped with a special fixture for use in driving the gas
plugs down firmly into the shells. The machine spindle car-
ries a heavy flywheel A to give the necessary momentum.
The fixture B in which the work is held is pivoted on the
table of the drilling machine so that it may be swung out
of the way of the flywheel for setting up the work and re-
moving the shell after the plug has been driven home, a stop
being provided for locating the work under the spindle.
78 MACHINING BRITISH SHELLS
The end of the spindle is fitted with a wrench which en-
gages the triangular nut on the disk when the spindle is fed
down. When engagement is made in this way, the momen-
tum of the flywheel drives the disk home with sufficient
force to screw it firmly into place, after which the continued
motion of the spindle results in twisting the corners off the
nut.
It is now necessary to remove the projection from the
base of the gas plug, and face off the base of the plug. For
this purpose the shells are taken to an engine lathe equipped
with a Hannifin air chuck and a turret toolpost. The pro-
jection is removed by a roughing tool, after which the tur-
ret head is revolved to bring a finishing tool into position to
take a light cut across the entire base of the shell. The tur-
ret head is again rotated to bring a third tool carrying a
hardened tool-steel roller into position. This roller is used
to spin over the slight seam between the plug and cavity
in the shell. The result is that any slight burr which was
raised at the joint during the turning operation is rolled
down, making the joint so smooth that it can hardly be seen.
Pressing and Forming the Copper Band. The shells
now go to a West Tire Setter Co. banding press, where the
copper band is pressed into the groove. After this has been
done, the shells are passed on to an engine lathe equipped
with a Hannifin air chuck and formed tools for forming
the bands. Two forming tools are used for this purpose,
the roughing tool being a radial tool carried at the front of
the fixture bolted to the cross-slide, whereas, the finishing
tool is of the tangential type and is located at the back of the
fixture. The shells are then taken to a Dwight Slate stamp-
ing machine, where they are marked. They are then
washed in hot soda water to remove the grease, after which
they are washed in alcohol to remove all traces of soda. As
the shells come from the alcohol bath, they are taken out
and placed on an inclined table, on which they roll
down until they come into contact with an accumulation of
shells at the base. These shells are in a convenient position
for the man who performs the painting operation on the in-
side. The device used for this purpose consists of two rol-
MACHINING BRITISH SHELLS 79
lers, which are normally located beneath the surface of the
bench. When the operator is ready to paint a shell, he
takes it from the bench and places it in position over the
hole through which the rollers are raised by depressing a
foot-treadle. The result is that the shell is held between
two rollers which impart a rotary motion to it. The
painter then takes a round brush of suitable size, dips it
into the shellac pot and pushes it into the shell. An ex-
perienced painter can varnish shells very rapidly by this
method.
After the varnish in the shells has dried, they are in-
spected; the production is 1000 per day of twenty-three
hours. Eight shells from each day's production are sent to
the proving grounds for test, and as soon as a favorable
report has been obtained, the shells are shipped to the load-
ing factory.
CHAPTER V
MACHINING RUSSIAN AND SERBIAN SHELLS
FOLLOWING the forging of the Russian 3-inch high-explo-
sive shell, Fig. 48, the first machining operation is cutting
off the open end. This is done in a Curtis & Curtis shell
cutting-off machine, as shown in Fig. 49. The forging is
located by means of the gage shown at the front of the ma-
chine, and the cutter head, carrying four radial cutters, is
rotated about the stationary shell. The cutters are auto-
Machinery
Fig. 48. Russian 3-inch High-explosive Shell and Plug
matically fed into the work and at the end of the cut are
returned to the starting point. The cutting is done at a
work speed of 65 surface feet per minute, and a lubricant
called "Cut-cool" is used for cooling and lubricating the
work. The wall of the shell is about 1/2 i ncn thick, and
the cutting off is done at the rate of fifty shells per hour.
On an average, 100 shells are cut off before the cutters
80
MACHINING RUSSIAN SHELLS
81
require grinding. The base end is now centered in a Rock-
ford drilling machine provided with a special arbor mounted
on the table over which the shell is slipped. After being
centrally located, the shell is drilled and countersunk with
a combination center reamer.
Heat-treating Russian High-explosive Shells. It is the
practice of one plant to heat-treat the Russian high-explo-
Fig. 49. Cutting off Open End of Shell Forging
sive shell before any of the important machining operations
are performed ; in fact, it is heat-treated after the centering
operation just described. Fig. 50 shows the furnace used
for heating the shell previous to quenching ; this is designed
and built by the Laconia Car Co., and is shown in detail in
Fig. 22. The shells are loaded into the furnace seven at a
82 MACHINING RUSSIAN SHELLS
time by a special fork mounted on wheels, as shown in Fig.
50. The furnace holds thirty-five shells, and it requires
thirty-five minutes to heat one lot of shells to the desired
temperature 1470 degrees F. (about 800 degrees C.). In
removing the shells from the furnace, the fork is rolled
under a layer of seven shells, which are pulled out, the
shells are gripped by a pair of tongs, and quickly immersed
in a bath of running water. They are placed on racks at
Fig. 50. Heating Russian High-explosive Shell Forgings for
Hardening
the bottom of the bath and allowed to get thoroughly cool
before removing.
The tempering is done in lead baths, also designed and
built by the Laconia Car Co., which are 34 inches wide, 34
inches high, and 4 feet 9 inches long. The lead pot proper
is of cast iron with one-inch walls, and measures 12 1/ by
14 by 24% inches. It is surrounded by a 1%-inch firebrick
lining. One burner is used to heat the lead bath to 1100
MACHINING RUSSIAN SHELLS 83
degrees F. (about 600 degrees C.) ; this burner consumes
41/2 gallons of fuel oil per hour. The shells are completely
submerged in the bath for seven minutes, then taken out
and allowed to cool slowly in the sand. To keep the shells
below the surface of the lead bath, they are suspended on
pins held on a crank, which is turned to force the shells
down or bring them up as required. Five men, with the aid
of three muffle furnaces and two lead pots, can heat-treat
100 shells per hour.
Rough-turning External Diameter. Following heat-
treating, the shells are rough-turned in a 16-inch lathe, as
Fig. 51. Rough-turning External Diameter
shown in Fig. 51. The shell A is supported at the closed
end on the lathe center, and is supported and driven from
the open end on the taper mandrel B. This resembles a
reamer in shape, but is not provided with cutting edges.
A single cutting tool is used and the depth of the
cut varies from 3/16 to % inch on the diameter. The work
is rotated at a surface speed of from 60 to 70 feet per min-
ute, and the feed is 1/16 inch per revolution.
Machining Interior of Russian High-explosive Shell.
The boring, counterboring, and reaming operations on the
interior of the Russian high-explosive shell are performed on
a turret lathe, as shown in Fig. 52. The order of opera-
84 MACHINING RUSSIAN SHELLS
tions is as follows : First, bore mouth of shell with boring
tool A; second, rough-drill entire length of shell with tool
B; third, finish-drill with tool C; fourth, finish bottom of
shell with tool D; fifth, finish-ream entire length of shell
with tool E; and sixth, counterbore with tool F.
Following the operations on the inside, the shell is held
in a three-jaw chuck on a Davis lathe, and the solid end is
rough-faced. After this, the shell is again chucked and the
mouth is recessed preparatory to threading. Following
this, the shell is held in a four- jaw chuck, as shown in Fig.
Fig. 52. Boring, counterborlng and reaming Cavity of Russian
High-explosive Shell
53, the outer end being supported by a steadyrest. The
operations performed at this setting consist in roughing out
the thread with tool A, taking a light cut across the end with
tool B, and finishing the thread with tap C.
Final Turning, Facing, and Banding Operations. The
base end of the shell is now finish-faced, the corners rounded
slightly, and the band groove cut. The next step is to ma-
chine the under-cut in the band groove, which is performed
by means of a special fixture. After this, the adapter or
MACHINING RUSSIAN SHELLS 85
nose is fitted into the end of the shell, and the end of the
shell is machined to shape. This operation is performed by
Fig. 53. Facing and threading Nose of High-explosive Shell
Fig. 54. Turning Radius on Nose of Shell
inserting a nose plug that is used as a center, as shown in
Fig. 54. The radius turning is done by means of a former-
86 MACHINING RUSSIAN SHELLS
plate A, against which the roll B held on the carriage is
pulled by a heavy weight attached to chain C. Grinding of
the body of the shell is now performed on a plain grinding
machine, in which the three-operation method is employed.
This is followed by pressing on the band, which is done in a
West Tire Setter Co. shell banding press. The rifling band
is now formed to the required shape in a Jenckes machine,
as shown in Fig. 55. Here, the shell is held in a three-jaw
chuck and the band is formed to shape by a single forming
cutter. Proper location of the shell in the chuck is ob-
tained by a gage located within the chuck.
Fig. 55. Turning Copper Band on Jenckes Machine
Machining the Adapter or Nose. The nose or adapter
A, Fig. 48, for the Russian high-explosive shell is turned
from bar stock in a 314-inch Gridley automatic turret lathe.
The first operation, after feeding the stock to the stop, is
drilling and rough-turning the outside and thread diameter.
These operations are performed from the turret and the
work speed is 120 R. P. M., the feed of the tools being 0.009
inch per revolution of the work. The tools held on the
second turret face counterbore and finish-turn the thread
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87
88
MACHINING SERBIAN SHELLS
out the center hole and cutting the internal thread ; this is
done on a 14-inch lathe. The first step is to take a light
finishing cut from the hole, after which it is threaded. The
production is about four pieces per hour. The drilling,
counterboring, and tapping of the hole for the set-screw B,
Fig. 48, comes next, and this is performed on a three-spindle
sensitive drilling machine; the production is twenty pieces
per hour. The two wrench holes C are then milled in a hand
milling machine, one at a time ; the production is sixty per
hour.
0.590
0.010
--
Machinery
Fig. 56. Serbian 75-millimeter High-explosive Shell
Machining Serbian 75-millimeter Shells. After the
forging has been completed, the first machining operation
on the Serbian 75-millimeter high-explosive shell shown in
Fig. 56 is cutting off the open and closed ends; the full
series of operations is given in Table III. The cutting of
the ends is done on an Espen-Lucas cold saw, as shown in
Fig. 57, at the rate of 160 per day. In this operation, in
addition to cutting off the excess stock on the open end,
about 3/16 inch of stock is removed from the closed end of
MACHINING SERBIAN SHELLS 89
the forging. The illustration shows that three shells are
loaded in one side of the machine by the swinging arm car-
rying the three gages while the saw is operating on the
three shells on the other side.
Following this operation comes the centering, which is
done on an engine lathe, as shown in Fig. 58. The man-
drel on which the work is held carries two sets of three
fingers that are expanded by a tapered draw-in bar operated
by a handwheel at the rear of the spindle. A combination
drilling and centering tool is used, and the production is 300
shells per day.
Fig. 57. Cutting off Excess Stock from Open and Closed Ends of
Forging
Turning and Boring. The shells now go to the turning
department where the first operation is facing and beveling
the closed end. Reference to Fig. 56 will show that the
Serbian shell has a pronounced bevel at the base end, and
this is roughed out at this time and the base faced, leaving
a teat about 11/16 inch in diameter. The facing and bevel-
ing is done on a 21-inch engine lathe, using two tools, one of
which cuts the bevel and the other faces the end. The cut-
ting speed is 65 feet per minute ; the production is from fifty-
five to sixty shells per day.
The next operation is rough-turning, as shown in Fig. 59.
90 MACHINING SERBIAN SHELLS
This is accomplished on a 17-inch engine lathe, at a work
speed of 44 surface feet per minute. The amount of metal
removed averages % inch on the diameter, and the feed is
0.024 inch per revolution of the work. This rough-turning
operation leaves the shell about 0.050 inch larger than the
finished size. The production is from fifty-five to sixty
shells per day. Following this, a semi-finish cut is taken
from the external diameter on a 17-inch engine lathe. For
this operation the work speed is 55 surface feet per minute.
The amount of metal removed is 0.025 inch on the diameter,
Fig. 58. Centering Closed End of Forging
and the feed is 0.040 inch per revolution. The production is
from ninety to one hundred shells per day.
The machining operations on the cavity of the shell are
performed on double-spindle flat turret lathes. In the first
position, the operation performed is rough-boring with a sin-
gle-point tool, removing 14 inch of stock from the diameter ;
second, roughing out taper with a flat boring tool and re-
cessing mouth with another tool held in the same bar ; third,
finish-boring full length of hole with a combination straight
and taper boring tool, also boring diameter to be threaded ;
(The boring tool-holder used carries two blades, one set at
right angles to the other ; the first tool bores the taper sec-
MACHINING SERBIAN SHELLS 91
tion and part of the straight section, whereas, the second
tool finishes the straight section only.) ; fourth, tapping
mouth end of shell. The production is thirty-four shells
per day.
A center plug is now screwed into the open end of the
shell and it is taken to the 21-inch engine lathe shown in
Fig. 60. The lathe is provided with a turret toolpost, and
carries three cutting tools and a knurl. The first operation
is to cut the groove with a broad-nose tool ; second, cut two
concentric rings (one for crimping in cartridge case) with
Fig. 59. Rough-turning External Diameter of Shell
a forming tool; third, under-cut base side of band groove
0.010 inch under-cut ; fourth, knurl band groove. The pro-
duction is from ninety to one hundred shells per day. The
shell is now taken to a 17-inch engine lathe, where a light
cut is taken from the external diameter, leaving it 0.015
inch over size. The turning commences at the rifling band
groove and terminates at a point about two inches from the
nose. The production is from 100 to 110 shells per day.
Finishing the Machining. Following this is the final
finishing, which is accomplished in a 17-inch engine lathe.
92 MACHINING SERBIAN SHELLS
Two tools are used for this operation ; one is set to the fin-
ished size of the shell at the base end back of the band
groove, and the other is set for the reduced size. The pur-
pose of this reduction is to allow clearance for the shell in
passing through the gun. The production is 120 shells per
day. The projection on the base end of the shell is now re-
moved on a band saw. This is done at the rate of two shells
per minute. After sawing off the center projection, the
base end is squared up on a 17-inch engine lathe. The tur-
ret toolpost carries two tools ; one of these faces the end a'nd
the other trues up the bevel. The production is from 110 to
120 per day. Before any other operations are performed on
the shell, the ogive is assembled.
Fig. 60. Turning and Knurling Band Groove
Machining Ogive for Serbian Shell. The ogive that fits
in the nose of the Serbian 75-millimeter high-explosive shell
is turned out from bar stock containing about 50 points
carbon. The first operation is performed on a 41/4-inch
Gridley single-spindle automatic. The bar is fed to the
stop located on a "corner" of the turret slide ; the operations
are : First, drill the small hole, and, at the same time, take a
light cut from external diameter and face end of work;
second, bore hole from turret, also chamfer inside with a
hook tool; third, neck at base of thread with a regular
Gridley internal necking tool, and, at the same time, form
MACHINING SERBIAN SHELLS
93
outside diameter to full width with a forming tool carried
on the cross-slide ; fourth, cut off. For centering, boring,
and facing, the stock revolves at 140 R. P. M. and the feed
is 0.010 inch per revolution. For forming, the speed is
slowed down to 80 R. P. M. and the feed to 0.008 inch per
revolution. The cutting off is done at a spindle speed of
140 R. P. M. with a tool feed of 0.012 inch. Production is
eight per hour.
The cutting of the internal thread is done on an "Automa-
tic" threading lathe,
using a circular tool
on the bar. The spin-
dle of the machine ro-
tates at 72 R. P. M.
and it takes from
fifteen to twenty
passes of the tool to
complete the thread.
The production aver-
ages six pieces per
hour. The thread on
the external diameter
is cut on a turret lathe,
where the work is held
on an expanding
threaded-stud m a n -
drel. The operations
are : First, face the
Seat On the Under Side Fig - 61> Assembling Ogive In Shell Nose
of the ogive that comes in contact with the front end of the
shell; second, thread external diameter; third, chamfer
thread and burr hole. The facing and burring operations
are accomplished at a spindle speed of 60 R. P. M., whereas,
for threading, the speed is cut down to 24 R. P. M.
Setting in the Ogive. After the ogive has been com-
pletely machined, it is assembled in the nose of the shell,
which is done on a drilling machine, as shown in Fig. 61.
The shell is gripped in a hinged fixture fastened to the table
of the drilling machine and a special tool similar in shape
94 MACHINING SERBIAN SHELLS
to an inverted cone, the inside surface of which is serrated,
is used to assemble the ogive in the shell. The ogive is
started into the shell by hand and then the tool is brought
down in contact with it, driving it down to the seat.
The shell is now taken to a 17-inch engine lathe where
the radius is turned, as shown in Fig. 62. Here it is
gripped in a collet chuck, being located centrally in this
chuck by means of a special gage located on the tailstock
spindle. After clamping, the turning tool A is brought in
contact with the work and is guided in its operation by
Fig. 62. Turning Ogive in Open End of Shell
means of a former-plate B fastened to a fixture held to the
bed of the lathe. The movement of the cross-slide is con-
trolled by a roller C that makes contact with this former-
plate, the latter being kept in contact with the plate by
means of two ropes to which weights are attached and
which run over pulleys, as illustrated. The production is
seventy per day.
Following the turning of the nose, the copper band is
now pressed into the groove in a West Tire Setter Co.'s
banding press. The bands are annealed before being
MACHINING SERBIAN SHELLS 95
pressed on the shell and two squeezes are necessary to com-
press the band into the groove. The copper band is now
turned to shape in a 14-inch engine lathe carrying a special
forming tool that covers the entire width of the band. This
operation is handled at the rate of ninety shells per day.
The shells are now inspected before they go into the hands
of the government inspector. The inspection operation
consists in checking up the diameter of the band and the
ogive to see that they are held tightly in place. The shell is
stamped on a Noble & Westbrook stamping machine. The
Fig. 63. Spraying Interior and Exterior of Shell with Copal Varnish
stamp is in the form of a roll that is passed over the end
of the shell, pressure being applied by means of a foot-
treadle. Prior to the varnishing which follows, the shells
are washed, after which they are dried.
Varnishing Interior and Exterior of Serbian Shells.
The shells now go to the lacquering and spraying depart-
ment where they are sprayed inside and outside and painted
on the outside previous to shipment. For the spraying of
the outside of the shell, a special De Vilbiss spraying torch
is used as shown to the right in Fig. 63, whereas the inter-
nal diameter is sprayed on a special machine shown in the
96 MACHINING SERBIAN SHELLS
background of the same illustration. Copal varnish is used
for spraying; this prevents the high-explosive from coming
into contact with the shell.
Internal Spraying Machine. The operation of the inter-
nal spraying device is more clearly shown in Fig. 64. For
this operation the shell A is placed on two pairs of rollers
B, which are rotated by a one-half horsepower electric mo-
tor. The shells revolve at the rate of 300 R. P. M. and they
are placed on the rollers and removed from them after the
spraying is done and while the rollers are still in motion.
Fig. 64. De Vilbiss Spraying Machine for coating Interior of High-explosive
Shells
The rollers are driven by means of a chain from the motor
through a countershaft. The operation of the spraying
member of the machine is as follows : With the rollers in
motion and the machine in the position shown in Fig. 64,
lever C is thrown to the left to start the machine ; this re-
leases a catch that holds lever D in a neutral position. The
releasing of the catch allows a coil spring to pull lever D
into the position shown, this lever being connected to the
valve E. When this valve is operated, the air passes
through it to a cylinder provided with a piston, the forward
motion of which operates a cone clutch that starts carriage
MACHINING SERBIAN SHELLS
97
F moving to the right. When the carriage F strikes stop
H, the rod upon which it is held moves forward with the
carriage until the coil spring is pulled over the center line
of lever D, at which point valve E is operated to return the
carriage. At the same time that carriage F starts to move
to the left, the air valve starts the spraying device G.
There are two noz-
zles in the end of torch
/ that throw a stream
of varnish in two di-
rections. The end of
the shell as well as the
sides are covered as
the carriage moves to
the left. The varnish
or other material used
flows down through
the flexible metal hose
J from a five-gallon
container suspended
above the machine.
When the spraying
torch reaches the point
where the shoulder of
the ogive is coated, a
cam mounted on the
bed of the machine
trips the air valve K,
which stops the spray-
ing. This valve is in
circuit with the valve
that starts the spray
so that the air passes through both of them. (Valve K is
opened on the forward stroke by cam L, but the other valve
is closed at that time and the spray does not start.) The
carriage continues to the left until it strikes stop M, which
moves the rod N back to the point where the lever D is
Fig. 65. De Vilbiss Spraying Device used in
coating Exterior of High-explosive Shells
98
MACHINING SERBIAN SHELLS
pulled back by the spring. A trip serves as a stop to hold
lever D in a neutral position until it is again thrown. The
throwing of lever D into the neutral position releases the air
pressure on the piston holding the clutch in engagement,
and a spring pushes the clutch out, stopping the motion of
the carriage. The production is 400 shells per day.
External Spraying Machine. The special De Vilbiss ma-
chine for spraying the exterior of high-explosive shells is
shown in Fig. 65. The spraying of the outside is done after
the inside has been
sprayed. In spraying,
the shell, as shown in
Fig. 65, is placed on a
vertical revolving
spindle which is driven
by a one-sixth horse-
power electric motor
at a speed of about
250 R. P. M. through
a belt and friction
diskdrive. The
amount of spray is ad-
justed by changing
the position of the
wheel which engages
with the friction disk.
Lever A serves to
move the wheel in and
out of engagement and
is used to automatically stop and start the machine between
the spraying of the shells. The adjustable guard B is
mounted on post C and swings in against a stop which pulls
it into position and covers the copper driving band of the
shell, protecting it from the varnish. The shell is sprayed,
while revolving, with a De Vilbiss standard type L "Aeron"
shown at D, the operator holding this device in his hand
as shown in Fig. 63. The exhaust fan E removes the va-
pors caused by the spraying operation. This fan is oper-
ated by a one-half horsepower motor, entirely enclosed to
Fig. 66.
Painting Exterior of High-explosive
Shells
MACHINING SERBIAN SHELLS 99
protect it from the vapors, and the motor is automatically
cooled by the clean air being drawn through it by the action
of the fan. The production on this machine is between 400
and 500 shells per day.
Painting and Drying Shells. After spray ing, the shells are
placed in a Steiner baking oven heated to 300 degrees F.
(about 149 degrees C.) , where the shells are baked for eight
hours. They are then taken to the Canadian Fairbanks-
Morse painting machine shown in Fig. 66 where they are
given a coat of yellow paint. This painting machine con-
sists of a stand on which there are six spindles, each of
which rotates continuously. The shells are placed upon the
spindles, and, as they rotate, the painter holds his brush on
the shell and applies the yellow paint. The band is not
painted. One man can handle 250 shells per day with this
machine, although it is generally used with a battery of two
painters and one cleaner, when the average production is 750
shells. Once more the shells are placed in drying ovens
that are kept at a temperature of 150 degrees F. (about 66
degrees C.), and ten hours in these ovens completes the
drying of the shell; it would require twenty hours to dry
in the atmosphere. After drying, the shells are wrapped
in oil paper and packed ready for shipment.
CHAPTER VI
MACHINING FRENCH 120-MILLIMETER (4.72-INCH)
SHELLS
THE following description applies to the manufacture of
the French, 120-millimeter, high-explosive shell, which is
made from a seamless steel forging of the proportions shown
at A, Fig. 67. The forging is machined to the shape shown
at B and is then nosed-in, after which a second series of
operations is performed, bringing it to the shape shown
at C. The first operation is to pickle the forgings to re-
move the scale; this is done in a solution made up of sul-
phuric acid 1 part, water 10 parts. The temperature of
this solution should not be raised above 150 degrees F.
(about 66 degrees C.), as a higher temperature produces
fumes that are very annoying. The forgings are pickled
in this solution for one hour and then washed in a bath
of hot lime-water to remove all traces of the acid.
Sorting and Grinding Base End. The next operation
consists in sorting the forgings for size, with particular ref-
erence to the diameter of the cavity. The forgings are
received in the plant in three lots : Those exactly 94 milli-
meters (3.7 inches), those below, and those above this di-
mension. As a certain thickness of wall must be maintained
in this shell, the variation on the inside diameter of the
forging is carried to the external diameter, and on forgings
in which the cavity is larger than the exact size of 94 milli-
meters, the external diameter is made slightly larger to al-
low for this. It is therefore necessary that the forgings
be sorted and machined in different lots. After sorting,
they are taken to the Gardner double-spindle disk grinder
shown in Fig. 68, where the projection on the closed end is
surfaced for centering. Here the forging is held in a spe-
cial cradle fixture fastened to the swinging table and is held
100
MACHINING FRENCH SHELLS
101
in place by a clamp as shown. The wheel used is a car-
borundum cylinder wheel, 16 inches in diameter, with a
2-inch rim. The speed of the wheel is 1200 R. P. M., the
amount of stock removed from 1/32 to 1/16 inch, and the
production about thirty per hour. The complete order of
operations is given in Table IV.
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C Machinery
Fig. 67. Principal Dimensions of Forging and Condition of French
120-millimeter High-explosive Shell after First Series of
Machining Operations
Cutting Off Open End of Shell and Centering Closed End.
- From the disk grinder, the f orgings are taken to the
lathe shown in Fig. 69, where the open end is cut off, bring-
ing the forging to the desired length. The f orgings are
held on an expanding mandrel operated by a special air
chuck as shown in Fig. 70. Here the forging is shown, by
heavy dotted lines, gripped near the open end by an ex-
102
MACHINING FRENCH SHELLS
Fig. 68. Grinding Base End of French 129-millimeter High-explo-
sive Shell Forgings in a Gardner D.sk Grinder
Fig. 69. Cutting off Open End of High-explosive Shell Forging
H O
& J
O P^
roduction
Per Hour
O CO J^
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103
104
MACHINING FRENCH SHELLS 105
spindle. For this operation, the work is rotated at 70 feet
surface speed and the production is fifteen per hour. After
cutting off, the shell is gaged to length by the gage shown
in Fig. 71. This gage has graduations on the bar, giving
the limits.
The centering of the closed end is accomplished in an en-
gine lathe as shown in Fig. 72. The lathe is provided with
a Hannifin air chuck, operating an expanding mandrel of
Fig. 71. Gage used in testing Length of Trimmed Forgings
the type shown in Fig. 73, on which the forging is held.
This mandrel differs somewhat in construction from that
shown in Fig. 70 in that, in addition to clamping the forg-
ing, it centers it accurately from the internal diameter. In
construction, this mandrel comprises a main sleeve A, which
is screwed onto the spindle of the machine, and inside of
which passes a rod B and sleeve C. Rod B and sleeve C
106 MACHINING FRENCH SHELLS
are provided with tapered bearings that operate clamp-
ing blocks D and E against the tension of flat springs F
and G. These blocks are located equidistantly around the
circumference of the mandrel 'and engage the interior of
the forging near the base end and about 11/2 inch from
Fig. 72. Centering Closed End of Forging
the open end, respectively. Sleeve C of the chuck is forced
forward when rod B is drawn back and vice versa.
Centering is done with a United States electric drill held
in a cradle A, Fig. 72, which is fastened to the cross-slide
of the lathe and consequently moves with it. The center-
ing tool is guided by a plate B fastened to the cross-slide
which holds the tool in line with the axis of the machine
107
108 MACHINING FRENCH SHELLS
and drill spindles. The center hole is drilled and counter-
sunk % i ncn deep. The work is rotated at 25 feet surface
speed and the drill at 175 surface feet; the production is
forty-five shells per hour.
Fig. 74. Facing off Closed End of Forging to Lengtfi
Facing Off Closed End and Gaging for Length. After
centering, the closed end of the forging is faced off to the
required length, as shown in Fig. 74, the forging being held
on an expanding air-operated mandrel of the type shown in
Fig. 73. The desired length is secured by a swinging tool-
setting gage A held in a bracket fastened to the bed of the
MACHINING FRENCH SHELLS
109
lathe. In facing, from !/2 to % inch of stock is removed;
the work is rotated at 70 surface feet per minute and the
feed is by hand. The production is six shells per hour.
The next operation consists in gaging the trimmed forg-
Fig. 75.
Gaging Total Length of Trimmed Forging Prior to
Turning
ings for over-all length, as shown in Fig. 75. The gage used
consists of a plate, two pillars, and a cross bar. The plate
has a slot so that the teat on the end of the shell does not
interfere with the correct measurement of the over-all
length. The gage used in testing the length of the shell
110
MACHINING FRENCH SHELLS
after cutting off the open end is also shown at the right.
The allowable limit on length is 4 millimeters.
Rough-turning External Diameter. The rough-turning
of the external diameter is accomplished on a "Lo-swing"
lathe as shown in Fig. 76. Two tools are used for this
operation and remove about 3/16 inch of stock from the
Fig. 76. Rough-turning External Diameter In a "Lo-swing" Lathe
diameter. One tool starts at the center of the forging while
the other works from the closed end, so that the time re-
quired to turn the entire length of the shell is only equal
to that which would be necessary to turn one-half the
length with one tool. For this operation, the shell is held
on an expanding mandrel of the type shown in Fig. 73.
MACHINING FRENCH SHELLS
111
The first cutting tool turns straight for a short distance
until it approaches the nose, when it is backed out to en-
large the shell at that portion where it is nosed-in. The
shells are turned in this operation to within 2 millimeters
(0.0787 inch) of the finished size, the remainder being left
Fig. 77. Nosing-in Open End of Shell in a Beaudry Hammer
for grinding. The test for diameter is then made with a
set of Johansson gages, after which the shell is heated for
nosing-in. The production is four per hour.
Nosing-in Open End and Heat-treating. For nosing-in,
the shell is heated for a distance of six inches back from
the open end in the Frankfort furnace shown in the back-
112
MACHINING FRENCH SHELLS
ground in Fig. 77. The shells are left in the furnace for
thirty minutes and heated to a temperature of 1600 degrees
F. (about 870 degrees C.). The furnace is heated by nat-
ural gas, and holds ten shells at one time. The nosing-in
operation is accomplished in a 500-pound Beaudry ham-
mer, as shown in Fig. 77. For this work four men. are
required. One rotates the shell on its axis; another feeds
the shell into the hammer dies, which are split and of the
right shape ; the third operates the hammer ; and the fourth
takes the nosed-in shell out of the hammer and brings an-
Fig 78. Heat-treating Furnace and "Brush" for removing Scale
prior to immersing Heated Shell in Cooling Bath
other one to the power hammer ready for nosing-in. The
nosing-in is started with light blows, so as to make the
metal flow as evenly as possible; the blows are then in-
creased in severity until the shell has received about twenty-
five blows, which is ordinarily sufficient to complete the op-
eration. An improved method, however, eliminates one
man by rotating the shell on its axis by means of an air
drill. The production is thirty per hour.
After nosing-in, the shell is taken to a lathe where it is
gripped in a chuck, the nose bored out, and the end faced
off to length. The next operation is heat-treating, the
MACHINING FRENCH SHELLS 113
heating being done in a Frankfort furnace of the type shown
to the left in Fig. 78. The shell is left in the furnace for
twenty-five minutes at a temperature of 1800 degrees F.
(about 980 degrees C.). As soon as the shell reaches the
desired temperature, it is quickly removed from the furnace
Fig. 79. Dipping French High-explosive Shells in Special Cooling
Bath
and placed in the cooling bath, shown in Fig. 79 and in
detail in Fig. 80. Formerly the brushing device shown in
the foreground of Fig. 78 was used to remove the scale,
but this has been found unnecessary. Each cooling bath
accommodates only one shell and is so arranged that the
water circulates inside the cavity as well as around the ex-
114
MACHINING FRENCH SHELLS
ternal circumference. The shells are left in the cooling
bath for five minutes, after which tempering follows. The
Machinery
Fig. 80. Details of Cooling Bath shown in Fig. 79
quenching device shown in Fig. 80 does not provide for
rotating the shell when cooling. An improved device incor-
porates a rotating table for revolving the shell and thus
MACHINING FRENCH SHELLS 115
obtaining a more uniform hardness. The tempering opera-
tion, which follows, is accomplished by heating the shell
to 970 degrees F. (about 520 degrees C.) in a Frankfort
furnace and then taking it out and allowing it to cool off in
the air.
Inspecting for Hardness. The final inspection for hard-
ness is accomplished by means of a hydraulic testing ma-
chine, working on the Brinell ball principle, as is shown in
Fig. 81. The ball used is 10 millimeters in diameter, and
the pressure is 3000 kilograms (6613.8 pounds) for a pe-
riod of fifteen seconds. The diameter of the impression
Fig. 81. Testing Hardness of French 120-millimeter High-explosive
Shells
made with this ball must be 3.4 millimeters (0.1139 inch) ;
this corresponds to a hardness on the Brinell chart of 321.
After this testing operation, the shells are ready for grind-
ing. This Brinell test factor indicates an ultimate strength
of about 124 kilograms per square millimeter.
Pickling and Drying Partly Machined Shells. After
heat-treatment and testing for hardness, the shells are
pickled to remove the scale formed in heat-treating, and
dried before any further machining operations are per-
formed on them. For pickling, the shells are placed, open
end up, in a wooden rack and are immersed for forty-five
20:=
W via
116
MACHINING FRENCH SHELLS
117
minutes in a bath consisting of ten parts water to one part
sulphuric acid, and when lifted out are tipped so that the
pickling solution runs out quickly. After immersing in the
acid bath, the shells are washed in a solution of strong lime-
water, then in clear running water, and then dried in a coke
furnace, which is heated to 400 degrees F. (about 200 de-
Fig. 83. Boring and threading Open End of Shell on Jones &
Lamson Single-spindle Turret Lathe
grees C.). This furnace is 24 inches wide, 12 inches high,
and 48 inches long, and is tilted from the floor so that the
shells, when fed in at one end, roll down and out of the
other. It holds ten shells, which are left in it for forty
minutes, after which they are taken out and allowed to
cool in the air.
118
MACHINING FRENCH SHELLS
Boring and Threading Nose End. Following the pick-
ling of the partly machined shell, the first operation consists
in recentering the base end, which is done on a Williams
Tool Co. cutting-off machine that has been fitted up for
centering. Here a light cut is taken to true up the center ;
the time required is about ten seconds per shell.
Fig. 84. Finish-turning External Diameter in a "Lo-swing" Lathe
at the Rate of Four Shells per Hour
Following this, the shells are taken to the Jones & Lamson
turret lathe shown in Fig. 83. For this operation, the work
is held in a "Whiton" chuck and supported by a three-roll
steadyrest. The operation consists in rough-boring the
hole in the nose, finish-boring hole with an expanding bor-
MACHINING FRENCH SHELLS
119
ing-bar, reaming to 43.6 millimeters in diameter, rough- tap-
ping with Murchey collapsible tap, finish-tapping with
Murchey tap. For boring, the work is rotated at 50 surface
feet per minute, and for tapping at 30 feet per minute. The
production is seven shells per hour from each machine. The
shells are now removed from the chuck and the thread fin-
ished to exact size by means of a master tap ; this is really
an inspection operation. The shells are then washed in a
steam bath to remove all the oil and grease and are then
dried thoroughly. Hardened center plugs are afterwards
Fig. 85. Grinding Body of Shell on Norton Plain Grinding Machine
screwed into the open end of the shell to serve as a center
point when grinding and turning the external surface in
subsequent operations.
Finish-turning External Diameter of Shell. The finish-
turning operation is done on the "Lo-swing" lathe shown in
Fig. 84. Here two tools are used to finish the straight por-
tion; and when these have traveled about 6 inches on the
shell, a third tool A turns the radius on the nose. Another
tool, not shown, turns the band groove to width and depth,
then an under-cutting tool finishes the under-cut, and finally
the groove is knurled. The last operation is to bevel the
120
MACHINING FRENCH SHELLS
closed end with tool B. When a copper ring is used for
the rifling band, only one side of the groove is dovetailed,
but when a copper strip is used, both sides must be dove-
tailed. For the various turning operations, the work is
rotated at a surface speed of 50 feet per minute, and the
feed for the external straight turning is 0.020 inch per
revolution. The production is four shells per hour.
Grinding External Diameter. In the grinding operation
that follows finish-
turning and illus-
trated in Fig. 85,
about from 0.020 to
0.030 inch of material
is removed from the
diameter of the shell.
The machine is a Nor-
ton plain grinder car-
rying a Norton alun-
dum 20-inch diameter
by 2-inch face wheel,
grain 46, grade M, ro-
tated at 1275 R. P. M.
The grinding is done
only on the straight
portion, starting at a
short distance from
the base end, and pro-
ceeds straight until
Fig. se. pressing on copper Driving Band the enlargement near
in a West Tire Setter Co. Banding Press the noge ^ reached .
The wheel is then backed away from the work the required
distance, and the straight portion finished on the nose to the
point where the radius merges. Owing to the length of the
work, the traverse method of grinding is used. The wheel is
trued up after grinding every three shells. The production
is eight shells per hour from each machine.
Pressing On and Turning Copper Bands. When the
copper band is of the ring type, the pressing on is done in
a West Tire Setter hydraulic banding press, as shown in
MACHINING FRENCH SHELLS
121
Fig. 86. The inside diameter of this band is slightly larger
than the external diameter of the shell, and is located in the
correct position by means of the compressing dies, six of
which are held in the machine. It requires from two to
three squeezes to finish the pressing, and the production is
twenty shells per hour. Before pressing on, the copper
Fig. 87. Turning Copper Driving Band
Fig. 88. Weighing French 120-millimeter High-explosive Shell
rings are heated to a dark red, then dipped in water and
cooled to the temperature of the surrounding atmosphere.
Following pressing on of the band, the shells are taken to a
16-inch engine lathe, as shown in Fig. 87. The first opera-
tion is to take a rough cut over the external diameter of
the copper band with a turning tool, after which a form
122 MACHINING FRENCH SHELLS
Fig. 89. Gaging External Diameter and Thread in Nose
Fig. 90. Gaging Contour of French 120- millimeter High-explosive
Shell
MACHINING FRENCH SHELLS
123
tool finishes the copper band to shape and diameter. The
production is twenty per hour.
After turning the copper band, the center projection is
cut off the closed end of the shell on a Williams Tool Co.
cutting-off machine at the rate of twenty-four per hour.
The center plug in the open end of the shell is also removed,
leaving the shell in a suitable condition for weighing and
inspecting.
Inspection. -- The first inspection is for weight as shown
in Fig. 88. The correct weight is 16 kilograms, 750 grams,
Fig. 91. Gaging Angle on Base End of Shell
and the tolerance is 200 grams (35 pounds, 6.97 ounces,
7.05 ounces). The first gaging test made is that for
"bulge diameter." In this test, illustrated in Fig. 89, two
ring gages are used. The diameter over the bulge is 119.6
millimeters plus 0.00 millimeter, minus 0.15 millimeter. The
"go" size must pass over the bulge, whereas, the "not go"
size must stop on it, as shown. The next test is made over
124
MACHINING FRENCH SHELLS
the copper band ; for this, snap gages of the horseshoe type
are used. The limits are 121.5 millimeters plus 0.15, minus
0.00 millimeter. The third test is for over-all length,
which is accomplished by means of a gage similar to that
illustrated in Fig. 75. With a gage of a similar kind, the
thickness of the closed end is measured from the nose. The
next test is the diameter across the nose. This is made
Fig. 92. Testing for Strength in a Metalwood Hydraulic Press
with a flat gage and the limits are 55 millimeters plus 1.0,
minus 0.00 millimeter. The master thread gage is next
screwed into the nose to see if the thread is correct ; after
this the plug is tried for diameter at root of thread ; these
gages are all shown in Fig. 89. The next test is for the
contour, which is made as shown in Fig. 90. A long flat
gage that covers the entire length of the shell and also the
contour at all points, when laid across the shell as illus-
MACHINING FRENCH SHELLS
125
trated, shows whether the shell has been turned and fin-
ished to the correct shape or not. Every point on the shell
must check up to the templet. The next test consists in
testing the angle at the closed end of the shell, as shown in
Fig. 91. The maximum diameter is 118.5 plus 0.25 milli-
meter, and the minimum diameter is 110.5 millimeters.
Testing for Concentricity. The next important test is
for concentricity. In this test, as illustrated in Fig. 93, a
counterweight gage A
having two arms and
counterweighted o n
one end is fastened to
the base end of the
shell. The shell rests
on hardened strips
fastened to a cast-iron
plate and is located at
right angles to the
hardened pieces by
pins driven into the
plate. It is then rolled
over and must balance
perfectly when the
gage is in place. The
heavy side of the shell
is first found by rotat-
ing it on the parallel
ways and then the
weight is located on
the light side. The moment of rotation must equal the
amount of eccentricity from the center of gravity times
the weight of the shell, as worked out from the formula :
WS = PR
in which W = weight of shell ;
P = weight used on stem of gage ;
R = distance from center of shell to center of
weight P;
Fig. 93. Gaging Concentricity of Shell
126 MACHINING FRENCH SHELLS
S = maximum eccentricity from center of gravity,
which on this size of shell is 0.7 millimeter.
As W y P, and R are known, S may be solved in the for-
mula given. If S is found to be 0.7 millimeter or less, the
shell is passed. If, however, S is found to be more than
0.7 millimeter, the eccentricity is too great ; P and R may be
standardized for the maximum eccentricity, thus avoiding
calculating.
Testing French High-explosive Shells for Strength. -
Every shell after machining and inspection is tested for
strength in a hydraulic press of the type shown in Fig. 92 ;
this particular machine is made by the Metalwood Mfg. Co.,
Detroit, Mich. Previous to testing, the shells are filled
with water and placed in the machine. A pressure equal
to 650 kilograms per square centimeter (9500 pounds per
square inch) is then maintained on every shell for about
ten seconds, after which the shell must show no leaks nor
cracks. Following the testing operation, the shell is ex-
amined for cracks, etc., and is then inspected by French
officials. One shell in every hundred is given every test
by an official. The last operation consists in greasing and
packing the shells ready for shipment.
CHAPTER VII
MACHINING BRITISH HOWITZER SHELLS
THE British, 4.5-inch, howitzer, high-explosive shell,
shown in Fig. 94, starts with a cast billet about three feet
long, which is subsequently cut into shorter lengths and
forged to approximate shape. There are about thirty-two
machining and inspection operations on this shell, and the
average time required to produce one shell complete and
ready for shipment is one hour, thirty-six minutes. The
Machinery
Fig. 94. British 4.5-inch Howitzer High-explosive Shell
equipment used for this purpose, however, was not origin-
ally laid out for handling this work; in fact, the only special
equipment purchased to turn a car shop into a shell plant
was small tools and a few attachments for engine lathes.
The order of the various operations is as follows : The
shell is marked off and the amount of material to be re-
moved from each end is indicated. The open end is then
127
128
MACHINING HOWITZER SHELLS
cut off, as shown in Fig. 95, in an axle lathe that has been
fitted up for this work. This axle lathe is of the double-
head type, so that two men can work on one machine. The
production is 250 in ten hours. The wall of the forging
is about 13/16 inch thick, the cut-off tool % inch wide, and
the speed 15 R. P. M. ; the cutting tool is fed in by hand.
Fig. 95. Cutting off Open End of Forging
Facing and Rough-boring. The second operation con-
sists in facing off the closed end in a boring mill where
twenty-four of the f orgings are held in a fixture ; two tools
are used. The depth of cut is 14 i nc ^ an( * the feed 1/16
inch per revolution. The table of the machine is operated
at 120 R. P. M. and the production is about 220 in ten hours.
MACHINING HOWITZER SHELLS
129
The third operation consists in rough-boring the interior
to 3% inches in diameter in a four-spindle rail drill operated
by two men, as shown in Fig. 96. The hole is 9% inches
deep and is finished in one cut. A cutting lubricant known
as "Mystic," made by the Cataract Refining Co., is used
to keep the tools cool. The shell being rough-bored is held
Fig. 96.
Boring out Cavity of 4.5-inch Howitzer High-explosive
Shell
in a spring collet chuck attached to a slide that works in
guides located on the table. The boring tools are rotated
at 50 R. P. M. and the spindle moves down with a speed of
about 1/16 R. P. M. The production is 240 in ten hours.
The fourth operation consists in centering the base end
in an 18-inch engine lathe. The forging is held on an ex-
130 MACHINING HOWITZER SHELLS
panding mandrel and the center hole in the base end is first
drilled and then centered with a centering tool. The pro-
duction is 400 in ten hours.
Rough-turning. The fifth operation is rough-turning in
an axle lathe. The shell is again held on an expanding
mandrel and turned up for a distance of 9*4 inches from the
base end. The feed is 3/32 inch per revolution and the
depth of cut is 7/32 inch. The speed of the work is 50
R. P. M. The production is 140 in ten hours.
Spot-drilling, Bottoming, and Finish-boring. The sixth
Fig. 97. Finish-boring, reaming and facing 4.5-inch Howitzer
High-explosive Shell
operation consists in spot-drilling on the inside with an
end-cutter on a 28-inch, upright, drilling machine. The
work is held in a collet chuck and about % inch of metal
is removed. The spot-drilling tool is rotated at 140 R. P.
M., and is operated by hand feed ; the production is 300 in
ten hours. The seventh operation consists in hogging out
the pocket at the bottom with a form cutter, held in a bor-
ing-bar in a wheel boring lathe of the vertical type. This
tool is rotated at 48 R. P. M. and just cuts at the bottom;
it is operated by hand feed. For this operation the forg-
ing is held in an expanding collet chuck and the production
is sixteen pieces per hour.
MACHINING HOWITZER SHELLS 131
The eighth operation consists in chamfering on a wheel
boring lathe with a tool that chamfers the inside of the
shell at the mouth only. This tool is rotated at 48 R. P. M.
and chamfers for a distance of about 1% inch down into
the shell, enlarging the shell from 3% to 4 3/16 inches.
The ninth operation, as shown in Fig. 97, consists in finish-
boring the inside of the shell and finish-chamfering the
mouth. The operation is to bore and face with an end
facing tool that is located from the bottom, then finish the
pocket at the bottom and chamfer. The machine used is
Fig. 98. Waving and Under-cutting Band Grooves
a Bertram 26-inch engine lathe provided with a turret, and
the shell is held in an expanding chuck and rotated at 80
R. P. M. The cuts vary from 1/32 inch to just cleaning up,
and the production is eighty in ten hours.
Grooving and Waving. The tenth operation is finishing
the nose on the outside diameter with two tools. The first
takes a straight roughing cut, the second turns the radius,
and a third tool held in the same toolpost finish-chamfers
the end. The machine used is a New Haven, 24-inch, en-
gine lathe. The center on the tailstock is brought in to
support the work, which is also held in a three-jawed chuck.
132 MACHINING HOWITZER SHELLS
The work rotates at 60 R. P. M. and the production is 220
in ten hours. The eleventh operation consists in taking a
finishing cut over the base, roughing out the band groove,
and finishing the external diameter back of the band groove,
on a New Haven, 24-inch, engine lathe. The production
is twelve per hour. The work is rotated at 60 R. P. M.,
and one turner and one form tool are used.
The twelfth operation is waving and under-cutting in a
New Haven, 24-inch, engine lathe, to which has been applied
a Bertram waving attachment, as shown in Fig. 98. The
work is held in a chuck of the three-jaw type and is sup-
ported at the opposite end by the tailstock center. The
Fig. 99. Boring out Closed End of Shell for Gas Plug and threading
waving tools are operated by a cam on the face of the chuck.
The work is rotated at 40 R. P. M. and the production is
twenty-five per hour.
Nosing-in, Boring, and Threading Nose. The thirteenth
operation is nosing-in, which is done in a Williams & White
bulldozer. The shell is heated in a furnace to a white heat
and is nosed-in in one blow. It requires three men to han-
dle this operation ; one looks after the furnace and two after
the machine. The production is 400 in twelve hours. Af-
ter cooling, the shell is brought back to the machining de-
partment where the fourteenth operation is performed.
This consists in boring out the closed end of the shell for
MACHINING HOWITZER SHELLS 133
the gas plug and threading on a Jones & Lamson, single-
spindle, flat-turret lathe, as shown in Fig. 99.' The opera-
tions are : Drill hole 1% inch in diameter, hog out with a flat
cutter, under-cut and face with a combination under-cutting
and facing tool, and thread with a Jones & Lamson regular
chasing attachment. The work for all operations except
threading is operated at 30 surface feet per minute, and the
production is ten per hour.
The fifteenth operation consists in machining the nose
on a Reed, 20-inch, engine lathe, provided with a turret
attachment, shown in Fig. 100. The operations are : Bore,
taking a 1/16-inch cut at a speed of 50 R. P. M., and face
off to length, rough out inside radius with a boring tool,
Fig. 100. Boring, facing and threading Nose End of Shell
feeding by hand ; finish inside radius to shape with a form
cutter; and tap for a distance of 2 inches with a Murchey
collapsible tap. The production is nine and one-half per
hour.
Finish-turning. For the sixteenth operation a center
plug is inserted in the open end of the shell. The external
diameter is then turned all over in an 18-inch Canadian
Machinery Corporation lathe. As shown in Fig. 101, two
cutters, which are held in the toolpost, are used for finish-
ing. The cut is about 3/64 inch deep, and the operation of
the tool-slide is controlled by a forming bar at the rear.
The feed of the tools is 1/32 inch per revolution; and the
speed, 100 R. P. M. The production is nine per hour.
134 MACHINING HOWITZER SHELLS
Miscellaneous Operations. The seventeenth operation
is sand-blasting the inside with an air nozzle inserted in the
shell; the production is about 200 in ten hours. The eigh-
teenth operation is preliminary inspection. The nine-
teenth is to screw in the base plug, and, at the same time,
wrench off the projection with a heavy wrench. The twen-
tieth operation is to face off the plug and round the edges
of the base on a Canadian Machinery Corporation 18-inch
engine lathe. The operations are: Take a roughing cut
across the base, roll in plate with a plain roller, and take a
finishing cut across the base. For these operations the feed
Fig. 101. Turning External Diameter to Size and Shape
is by hand and the cuts vary in depth from 1/16 to 3/16
inch. The speed of the work is 120 R. P. M., and the pro-
duction is fifteen per hour.
The twenty-first operation is stamping with hand stamps,
the work being held in a fixture while this operation is being
performed. Sixteen stamps are necessary and the produc-
tion is 295 shells in ten hours. The twenty-second opera-
tion is re-tapping the hole in the nose of the shell with a
Murchey tap, the shell being held in an Acme single-head
threading machine, carrying a chuck instead of a die-head.
The production is twenty-five per hour.
The twenty-third operation is screwing in the brass nose
MACHINING HOWITZER SHELLS 135
bushing by hand, holding the shell in a fixture. The twen-
ty-fourth consists in turning the brass socket in a McDou-
gal, 20-inch, engine lathe, one cutting tool being used; the
production is twenty per hour. The twenty-fifth operation
is cleaning out the shell with benzine and then varnishing
it with a brush. The shell is laid down on the bench, rolled
back and forth by the operator, and the interior varnished
with a brush shaped like a large toothbrush. Two men
are employed for this operation and the production is 400
in ten hours. The twenty-sixth operation is baking the
Fig. 102. Turning Copper Driving Band
varnish on the shell in an oven, which is heated to 300 de-
grees F. (about 150 degrees C.). This oven is kept at a
constant temperature and the shells are left in for eight
hours. They are then taken out and allowed to cool in the
air. As the furnace holds 240 shells, the production is 240
in eight hours.
Pressing on and Turning Copper Bands. The twenty-
seventh operation is pressing on the copper band, which is
done in a special banding machine having four hydraulic
cylinders. The production is 225 in ten hours. Turning
~f
O'tBQgiMyi _
jfcsKfij 9U
136
MACHINING HOWITZER SHELLS
137
the copper band is the twenty-eighth operation ; this is done
in a Walcott & Wood, 22-inch, engine lathe, equipped with
a Lymburner Ltd. band turning attachment, as shown in
Fig. 104. First Machining Operation on British 9.2-inch High-
explosive Shell Forging drilling Hole in Nose and facing
Fig. 102. This attachment carries two forming tools, one
on the front and one on the rear of the cross-slide. The
operations performed are : Rough-turn band with a tool on
the top of the slide, operated by a turnstile at the front;
138 MACHINING HOWITZER SHELLS
rough-form band to shape with a form tool; and finish
band with a forming tool held on a special attachment at the
rear of the machine and operated by a separate handle.
The work is rotated at 250 R. P. M. and the production is
twenty-five per hour.
The twenty-ninth operation is the final inspection. The
thirtieth, applying the first coat of paint, the base of which
is white lead; the thirty-first, applying the second coat of
yellow paint. After drying, the shells are again inspected
and packed ready for shipment, the plug, of course, being
screwed into the nose to prevent foreign matter from getting
into the cavity of the shell, and also to protect the threads
in the nose from bruises. The plug is retained in the shell
until it is removed for loading; it is then replaced and not
removed again until the shell reaches the field of operations,
where it is taken out and the detonating fuse substituted.
Machining 9.2-inch British Howitzer Shells. Starting
with the finished forging, which is made with a closed-in
nose and has been carefully annealed, the first machining
operation on the 9.2-inch British, howitzer, high-explosive
shell shown in Fig. 103 consists in drilling a two-inch hole
through the nose and in facing off the nose end of the shell
until the required length is obtained. These operations are
performed on a six-foot, radial, drilling machine, as shown
in Fig. 104, using a two-station jig that enables one side
to be loaded while the machining operations are being per-
formed on a forging located on the other side. The jig
A is in the form of an angle-plate, and the radial arm of
the machine is moved to bring the tool in line with the
work. The drilling is done at a cutting speed of from 60
to 65 feet per minute with a down feed of 1/64 inch per
revolution. The production is five and one-half shells per
hour, one man operating the machine.
Cutting-off and Rough-turning Operations. The next
operation is cutting off the open end, which is done on a
Pond 24-inch lathe. The forging is held in a "pot-chuck"
(see Fig. 106), and is gaged from the end just machined.
The surplus stock on the open end is cut off by means of a
special carriage carrying two cutting-off tools, and oper-
MACHINING HOWITZER SHELLS
139
ated by right- and left-hand screws, so that both tools are
at work at the same time. The blades of the cutting-off
tool are % inch wide, and the surface speed of the work is
from 70 to 80 feet per minute. One man operates two ma-
chines and cuts off seven shells per hour.
After cutting off, the straight portion of the shell is
rough-turned. For this operation the shell is held on a
mandrel that has two sets of expanding plungers and the
work is done on a Pond 24-inch lathe. Two cutting tools
are used and remove a total of % inch on the diameter in
Fig. 105. Turning Radius on Nose on a 24-inch Engine Lathe
one cut. Each tool removes % inch, and works at a cut-
ting speed of from 70 to 80 surface feet per minute. As the
forcings vary somewhat, it is often necessary to take two
cuts to finish. The longitudinal feed is y 8 inch per revolu-
tion of the work. At this setting, the nose of the shell is
not touched ; the next operation is the roughing of the
nose to the required radius on a Pond 24-inch lathe, Fig.
105. The shell is gripped from the internal diameter by ex-
panding mandrel A, fastened to the faceplate as shown.
140
MACHINING HOWITZER SHELLS
Two cutting tools are used which are guided in the cor-
rect path by a simple but satisfactory device. This radius
device comprises a special carriage B that is carried on a
bracket C bolted to the bed at the rear of the lathe. Lo-
cated on carriage B is a stationary slide D to which is
bolted a link E that serves to connect the cross-slide F with
the rear carriage. The cross-feed screw ordinarily used is
removed so that the motion of the slide F in a radial direc-
tion is controlled by the link E. In operation, as the front
carriage is fed toward the faceplate, the link E forces the
Fig. 106.
Rough- and finish-boring Internal Diameter on a 36-inch
Engine Lathe
cross-slide F back and thus guides the cutting tools in a
curved path. The correct starting and finishing points of
the radius on the shell are obtained by adjusting the screw
G. The production for rough-turning the straight diameter
and nose is one shell per hour.
Boring, Counterboring, Facing, and Threading Operations.
The boring is performed on a Pond, 36-inch, heavy-duty
lathe provided with a rack tailstock, as shown in Fig. 106.
For machining, the shell is held in a "pot-chuck" clamped
to the faceplate and is additionally supported by a steady-
rest as shown. The interior of this chuck is made an
MACHINING HOWITZER SHELLS 141
easy fit for the shell, which is held by contracting the split
chuck by clamping bolts as shown. Two three-tooth boring
reamers are used, one roughing and one finishing, which re-
move about y% inch from the diameter between them. The
roughing reamer is provided with high-speed steel blades
which are serrated to break up the chip, whereas the finish-
ing reamer is provided with smooth blades of high-speed
steel. The cutting speed of the reamers is from 74 to 78
surface feet per minute. The longitudinal feed is very
coarse (1/2 inch per revolution) until the radius is reached,
Fig. 107. Set-up on a 24-inch Engine Lathe for machining Band
Groove and cutting Wave Ribs
where it is reduced to 1/32 inch per revolution. The pro-
duction is one shell per hour.
Following the operation just described, a series of opera-
tions is performed on the nose of the shell on a Pond 24-inch
lathe provided with a four-sided turret. The shell is held in
a pot-chuck, but with the nose instead of the base end pro-
jecting. The operations are : Rough- and finish-bore open-
ing, rough-face end, tap and finish-face end. The finishing
cuts are taken at an average speed of 120 surface feet per
minute and the feed is 1/32 inch per revolution. The pro-
duction is two shells per hour.
142
MACHINING HOWITZER SHELLS
The reverse end of the shell is now machined, and, as in
the previous operation, is held in a pot-chuck. The work
is done on a Pond 24-inch lathe provided with a four-sided
turret. The operations are: Face off base end, bore and
counterbore, and chase thread for base plug. The cutting
speeds are 120 surface feet, feeds 1/32 inch per revolution,
and production, one shell per hour.
Finish-turning, Grooving, Waving, and Assembling Base
Plug. The finish-turning on the external diameter is done
on a Pond 24-inch lathe provided with a former plate, some-
what similar in design to an ordinary taper-turning attach-
ment. One cutting tool is used and one cut finishes the
work. The speed is 120 surface feet, and the feed 1/32
inch per revolution. The production is two shells in three
hours.
DRIVE
a \^_
1 C
UJ
\F
jo
La
{ F
?OM FACEPLATE
~~--.,.
--^ \ x CENTER
""""!' thi^
j; [PjL n
-
Machinery
Fig. 108. Diagram showing Details of Construction of Mandrel
used for holding Shell when performing Operation shown in Fig. 107
The shells are then taken to the Pond 24-inch lathe
shown in Fig. 107, where the band groove is cut and the
wave ribs produced. The shell is held on a special mandrel
A (see Fig. 108 for details of construction) which is driven
by a special faceplate B, Fig. 107, that carries the cam C
used in oscillating the rear waving slide D. The lathe car-
riage is provided with a turret toolpost E carrying four
tools that perform the following operations : Tools F neck
at the limits of the band groove, tool G roughs out the
groove to the top of the ribs, tool H under-cuts the edges
of the groove, and tool / roughs out between the wave
ribs. The wave ribs are produced by the special fixture D
held on the rear of the carriage. This comprises a slide J
which is oscillated by the cam C against the tension of a
MACHINING HOWITZER SHELLS
143
spring K, and carries a tool-holder L that holds the waving
tool M. Tool-holder L is adjusted for position by screw N.
This fixture is operated by bringing the cross-slide forward
and moving the carriage over until a roll (not shown) en-
gages with the cam C that imparts the required oscillat-
ing movement to slide /. The band grooves are cut and
ribbed at the rate of eighteen shells in ten hours. The
base plug and nose bushing are put in by hand. Each plug
is carefully fitted and cleaned, and is left partly screwed
in place until such time as the loading of the shell is fin-
ished.
Fig. 109. Set-up for turning Copper Band to Shape on a 24-inch
Engine Lathe
Banding and Band-turning Operations. The pressing on
of the copper driving band is performed in a Dudgeon hy-
draulic banding press. The copper bands are heated to a
bright red in a "Best" oil furnace, and when they have at-
tained the correct temperature they are quickly removed and
placed in the banding press. The shell is then placed in the
press, the band being slipped over it and located by the dies
in the correct relation to the groove. As the press is operated,
six dies are forced in radially and compress the band into
the groove. After the first squeeze, the shell is turned 30
degrees and given another squeeze. The production on this
operation is about twenty shells per hour.
144
MACHINING HOWITZER SHELLS
The copper band is turned on the Pond 24-inch lathe
shown in Fig. 109. Here it is supported and driven from
one end by a special driver A, Fig. 110, and is supported
on the nose end by a revolving center B. The cross-slide
carries a turret toolpost A, Fig. 109, holding four tools,
which, in conjunction with a forming tool on the rear of
the slide, rough- and finish-turn the band to shape. The
production is three shells per hour.
Weighing, Cleaning, Varnishing, etc. Upon the comple-
tion of the machining operations, the shells are weighed,
the limit in weight being 10 ounces either way from the
standard, which is 252 pounds. Working from the nose
\DRIVI!NG PIN
OMBINED DRIVER AND CENTERING CHUCK
REVOLVING CENTER
Machinery
Fig. 110. Diagram showing Method of holding and driving Shell
when performing Operation shown in Fig. 109
end, the shell is now washed out with soda water and then
dried, after which a coating of Copal varnish is sprayed
in with a Buffalo air-spray brush. The shell is swabbed
outside, while hot, with a light machine oil and then baked
for eight hours at a temperature of 300 degrees F. (about
150 degrees C.).
Because of their weight, these shells are too heavy to
handle by hand, so light air hoists are located over each
machine to facilitate handling. These hoists travel on a
continuous track, which runs down the aisle of the shop be-
tween two rows of machines along which the shells are kept
moving. Stamping, inspecting, etc. finish the operations on
the shell, after which it is ready for packing and boxing.
CHAPTER VIII
MISCELLANEOUS TOOLS AND DEVICES FOR SHELL
MANUFACTURE
BRITISH, 18-pound, high-explosive shells are made from
bar stock, the usual method being to rough out the hole
in a high-power drilling machine. Figs. Ill and 112 show
an efficient method of accomplishing this operation. The
machines used are Baker Nos. 310 and 315, vertical, high-
power, drilling machines (the latter size being of the extra-
heavy pattern) equipped with a special fixture a clamped
to the table. This fixture is provided with four tool-steel
holding jaws that support the bar in a vertical position, and
are operated by right- and left-hand screws by means of a
turnstile b. At A, Fig. Ill, is shown the first rough-drilling
operation, which is accomplished by means of a 1 13/16-inch
diameter high-speed drill driven at 175 R. P. M. with a down
feed of 0.020 inch per revolution. The drilling time is about
three minutes per shell; B shows the second operation,
which consists in removing the vee left by the point of the
drill, and rounding the bottom ; and C shows the final ream-
ing operation. In Fig. 112, D illustrates the special tool
used for machining the exterior of the nose of the shell.
This tool is designed along the principles of a hollow-mill
carrying one inserted high-speed steel blade. In this set-
up, a special bushed bracket is fastened to the top of the
fixture, to support the large nose turning tool.
Previous to cutting the thread in the nose of the shell, it
is necessary to recess it at the point where the thread ter-
minates, as shown at E. This is accomplished by a recess-
ing tool of the construction shown in Fig. 113. This tool
consists of a holder A provided with a tang fitting into the
drilling-machine spindle. This carries a sleeve B that is
145
146
147
148
MISCELLANEOUS TOOLS
operated upon by a spring C, lying between the recessed
shoulder of the sleeve and a washer D that is pinned to the
bar A. The recessing tool proper E is carried in an elon-
gated slot in the lower end of the bar A and is operated
by means of an angular slot in the bar through a pin driven
through the recessing tool. In operation, the drilling-machine
spindle is brought down until the sleeve B contacts with the
nose of the shell, whereupon, further downward movement
of the spindle compresses spring C and at the same time
forces out the recessing tool E, cutting an annular groove
in the interior of the nose. The last operation, as per-
formed in the drilling machine, consists in threading, and
Machinery
Fig. 113.
Special Recessing Tool used for performing Operation
E shown in Fig. 112
it is accomplished with a collapsible tap as illustrated at F,
Fig. 112.
The lay-out advocated by Baker Bros, for this work is a
gang of six machines, consisting of two No. 315 extra-
heavy pattern machines for the drilling and nose-turning
operations, and four No. 310 machines for the bottoming,
reaming, counterboring, facing, under-cutting, and tapping
operations. This gang of six machines gives a production
of eight shells per hour, and leaves them ready for the lathe-
turning operations.
Surfacing Gas Plugs on Besly Ring-wheel' Grinders.
The gas plug used in the base end of British high-explosive
shells is made from a forging and must be faced on the end
that is next to the shell. Several methods are used in sur-
MISCELLANEOUS TOOLS
149
facing the inner face of this plug; a very satisfactory one
is to grind it on a Besly, No. 14-16, wet, ring- wheel grinder,
shown in Fig. 114, which is equipped with a special rotary
chuck, shown in detail in Fig. 115. Fig. 114 shows two
operators at work grinding the face of gas plugs. The
jaws of this rotary chuck are threaded to grip the threaded
body of the plug when the latter is machined ; consequently,
the base is finished true with the threaded body of the plug.
For grinding, a cylinder type of wheel is held in the stand-
ard, Besly, pressed-steel, ring-wheel chuck. The wheel is
Fig. 114. Surfacing High-explosive Shell Gas Plugs on a Besly No. 14-16-inch
L "Wet" Ring-wheel Grinder
about 16 inches in diameter, 3 inches face. Gas plugs for
British 4.5-inch high-explosive shells can be turned out
from the rough at the rate of from sixty to eighty per hour
for one operator by this machine. The machine, of course, is
double-ended, so that two operators can work on one ma-
chine at the same time. The action of the grinding wheel
rotates the work while grinding, producing the desired
accuracy.
The Besly grinder shown in Fig. 114 is also used for
grinding off the projections on gas plugs and facing the
150
MISCELLANEOUS TOOLS
base end. On the British, 18-pound, high-explosive shell,
the projection on the end of the gas plug is about % inch
long and % i ncn * n diameter, of square section. (In some
cases this section is made triangular in shape.) On the
Fig. 115. Special Rotary Chuck used on Besly Disk Grinder for
surfacing Gas Plugs
Fig. 116. Three-Inch High-explosive Shell, showing Finish left
by Besly Grinder; also Two Types of Gas Plugs
Besly grinder, twenty-five shells can be ground per hour.
The grinding machine, of course, accommodates two opera-
tors, giving a combined production of fifty shells per hour
per machine. At the same time that the projection is re-
moved from the gas plug, the surface of the gas plug is
MISCELLANEOUS TOOLS
151
also ground, 1/32 inch of material being removed. The
diameter of the plug on the 18-pound shell is about 2^4
inches, as shown in Fig. 116. Where the projection on
the gas plug is triangular in shape, the production can be
Fig. 117. Testing Hardness of High-explosive Shells with Sclero-
scope
greatly increased because this projection is only % instead
of % inch high. On the type of gas plug here described,
the production is about 100 shells per hour per operator,
or 200 shells per machine. Fig. 116 shows a British high-
explosive shell that has been finished off on the base on the
152 MISCELLANEOUS TOOLS
Besly grinder illustrated in Fig. 114 and also the two types
of gas plugs referred to. The one shown at A is of trian-
gular section, whereas the one shown at B is of square sec-
tion with a hole in the center.
Testing Hardness of High-explosive Shells. When or-
ders for high-explosive and shrapnel shells were first placed
in the United States and Canada, considerable trouble was
experienced in getting shells to pass the government in-
spectors. While a large number of concerns were success-
ful in getting the shells finished to the required dimensions,
many experienced trouble in heat-treating shrapnel shells
and attaining the desired physical properties. The govern-
ment inspectors finally decided on using testing apparatus
that could be applied to every shell after heat-treatment
and thus check up the tensile strength of the shells. There
are two well-known methods of testing the hardness of
metals, the Shore and the Brinell. The Brinell is the older
and uses the instrument shown in Fig. 81; the Shore
makes use of the scleroscope shown in Fig. 117. The
British government has been using both of these methods
for some time, but, in general, on shell work, the Shore
method has been adopted because of the rapidity with which
the test could be made. Also it did not injure the parts
and could be used on hardened metal, for which the Brinell
method is not as adaptable.
Extensive tests have shown that there is very little dif-
ference in the results obtained with these methods. What
little difference there is, is due principally to the Brinell
indenting pressure, which is applied slowly and then left
on for fifteen seconds or more. The time taken and the
extreme stress imposed causes undue variation depending
on the ductility of the metal. In fact, the Brinell reading
is so influenced by ductility that claims have been made
that it shows the ultimate strength; as a matter of fact,
however, the reading taken by the Brinell method is an
expression of the elastic limit. The scleroscope, on the
other hand, imposes on the metal an instantaneous limited
stress, and thus causes only slight mechanical super-hard-
ening, so it logically preserves the original values and serves
MISCELLANEOUS TOOLS 153
to indicate the elastic limit without undue variation leaning
toward the ultimate strength. It is for this reason that
exact comparison between the two tests can only be made
on one kind of metal at a time or in a given state of heat-
treatment. On heat-treated steel used in shrapnel and high-
explosive shells, the ratio is given by Shore as 6.4, meaning
that if the scleroscope shows, for example, 50 hard, this
multiplied by 6.4 would give the Brinell hardness, or a value
of 320.
Hardness of High-explosive Shells. --The shells used by
the British government are made from a special tough alloy
steel, the required physical properties of which are con-
tained in the "raw" steel, so that it does not require to be
heat-treated after machining. Their specifications are :
Per Cent
Constituents Min. Max.
Carbon 0.55
Nickel 0.50
Silicon 0.30
Manganese 0.4 1.00
Sulphur 0.04
Phosphorus 0.04
Copper 0.10
This steel in an untreated condition must give a yield point
of 19 tons and a breaking strength of from 35 to 49 tons,
with an elongation of from 17 to 20 per cent. The scleros-
cope is used to test each bar of stock after the first external
cut or before any of the important machining operations
have been performed, so that any defects in the material
can be discovered before it has gone too far.
The French high-explosive shell is made from steel con-
taining a lower percentage of carbon and no nickel. The
specifications on the French high-explosive shell are :
Per Cent
Constituents Min. Max.
Carbon 0.30
Silicon 0.18
Manganese 0.50 0.80
Phosphorus 0.04 0.07
Sulphur 0.05
154 MISCELLANEOUS TOOLS
After hardening and tempering, a tensile strength of
125,170 pounds per square inch is required with an 18.3
per cent elongation. The elastic limit would be about
from 80,000 to 120,000 pounds per square inch, or as shown
in Fig. 117, from 43 to 52 hardness on the scleroscope and
from 275 to 333 on the Brinell instrument, respectively.
The elongation and ultimate strength are determined by-
testing a shell, selected at random, to destruction.
The Russian high-explosive shell has a chemical composi-
Fig. 118. Ford-Smith Plain Wide Wheel Shell Grinder
tion somewhat similar to the French. It is hardened and
tempered to show a physical property giving an elastic
limit of not less than 62,000 pounds per square inch, a ten-
sile strength of 118,000 pounds per square inch, and an
elongation of 10 per cent. These properties in a steel of
the chemical constitutents just given would give a sclero-
scope hardness of from 40 to 45 when heat-treated.
Grinding High-explosive Shells. The British high-ex-
plosive shell is not heat-treated, and, consequently, many
MISCELLANEOUS TOOLS
155
manufacturers are finishing the external diameter to size
and shape by turning ; others, however, are using the grind-
ing method. The turning method cannot be used as suc-
cessfully on the Russian or French shells, because these are
heat-treated. The practice followed in grinding high-ex-
plosive shells differs in various plants. The diagrams, Figs.
Machinery
Fig. 119. Diagram Illustrating Methods of finishing High-explosive
Shell Bodies by turning and grinding
119 and 120, show several methods that are employed in
grinding high-explosive shells on the Ford-Smith heavy-
type, plain grinder shown in Fig. 118. Considerable im-
provements have been made in grinding high-explosive
shells, especially as regards keeping the face of the wheel
true. When this method was adopted, it was thought that
156
MISCELLANEOUS TOOLS
it would be necessary to true up the face of the wheel with
a diamond truing device after grinding a comparatively
small number of shells. This, however, has not proved to
be the case, and the truing up of the face of the wheel can
be done quickly by hand by the use of a carborundum stick.
A comparatively large number of shells can be turned out
Machinery
Fig. 120.
Diagram illustrating Method of finishing High-explosive
Shells by grinding
with one truing of the wheel, and on the Ford-Smith ma-
chine a special wheel-truing device, as illustrated in Fig.
121, is used.
The diagram in Fig. 119 illustrates three methods of
grinding high-explosive shells of the 18-pound size. That
shown at A consists in finishing the nose of the shell on the
MISCELLANEOUS TOOLS
157
lathe, and then grinding the external diameter from the
band groove to the radius, with a two-inch face wheel, by
traversing the work past the wheel. In the method shown
at B, a six-inch face wheel is used ; this finishes the entire
body of the shell, except the nose, which is turned in the
lathe in one straight-in cut. The method shown at C is
that employed on the Ford-Smith grinder in British plants.
The nose is turned in the lathe and the body is ground with
a wide wheel, generally about 8i/ 2 inches. The grinding is
done completely across the shell, the band groove being
cut in a subsequent operation. The production obtained on
Fig. 121. Wheel-truing Device used on Ford-Smith Grinding
Machine
the 18-pound shell when these various methods are used
differs considerably. When using the method shown at A,
the production is about from fifteen to twenty per hour ; by
method B, from twenty to thirty per hour ; and by method C,
from twenty-five to thirty per hour.
Fig. 120 shows methods of finishing high-explosive shell
bodies by grinding all over; A and B show two methods
of finishing high-explosive shells on a plain grinder. The
procedure followed varies. In some cases, the body is fin-
ished first and the nose later, whereas, in others, the nose,
as shown at A, is ground first and then the body, as shown
158
MISCELLANEOUS TOOLS
at B. The method that is shown at C is being used in
Canada at the present time. In this method, wheels as
wide as lli/^ inches face have been used, covering the en-
Fig. 122.
Machine built by Spray Engineering Co. for spraying
Interior of High-explosive Shells
tire length of the shell. On the 18-pound shell, the produc-
tion varies from twenty to twenty-five per hour, whereas
on the 4.5 shell, using an 11^-inch face wheel, the produc-
tion is somewhat less.
MISCELLANEOUS TOOLS 159
The special wheel-truing device used on the Ford-Smith
plain grinder, shown in Fig. 118, is illustrated in Fig. 121.
This device is held on swinging arm bracket A, fulcrumed
on pin B, and located, when in position to true the face of
the wheel, by stud C. The holder D, carrying the diamond
tool, is provided at its rear end with a hardened cam sur-
face that is kept in contact with the forming cam E by
means of a spring located in the body of the attachment.
The method of operating this device is as follows : After
swinging the attachment into position and locking it, the
wheel slide is advanced until the diamond contacts with the
wheel ; crank handle F is then rotated. This carries a gear
that meshes with another gear in the enclosed case G. The
stud in this case extends down through the fixture and
engages another gear operating in a rack. Consequently,
the turning of this handle moves slide H back and forth,
and traverses the diamond holder past the face of the wheel.
This diamond truing device is only used occasionally to
bring the wheel to the correct shape and to dress up new
wheels; for slight dressing, a carborundum stick is used.
Varnishing Interior of High-explosive Shells. In Fig. 122
is shown a machine built by the Spray Engineering Co.,
Boston, Mass., provided with an apparatus for spraying
the necessary protective coating on the inside of a high-
explosive shell. The machine comprises a table with steel
supporting frames, and has the operating mechanism placed
beneath it. The coating material, such as varnish, as-
phaltum paint, and similar compounds, is carried in a tank
located above the operating table, and passes down the hol-
low tank supports to an adjustable measuring device which
controls the amount of material sprayed at each operation.
A system of levers controls the motion of this device, cut-
ting off the supply from the tank and admitting measured
quantities of material to a channel leading to the spraying
nozzle. The last part of this motion opens a connection to
a compressed-air supply, which drives the coating material
through the spray nozzles and distributes it evenly over the
surfaces to be covered. A high working speed is thus ob-
tained without waste of material and one setting of the
160 MISCELLANEOUS TOOLS
measuring device insures delivery of a fixed quantity of the
material to each shell.
To operate the machine, the shell is inverted over the hole
in the operating table. A slight pressure on the foot lever
connected with the operating lever moves the measuring
device and admits compressed air. Upon the removal of
pressure from the treadle, suitable coil springs return the
mechanism to its oringinal position, ready for the next
operation. A particular feature of the machine is the de-
vice for admitting a fixed amount of coating material at
Fig. 123. Mathews Gravity Carrier transporting Shell Forgings
each operation, which permits setting the mechanism to
repeat any predetermined coating operation on a large
number of similar parts. For readily changing over to dif-
ferent coating materials, drain valves and priming valves
permit a thorough cleaning of the measuring device and all
pipe passages without taking the mechanism apart. The
height of the spray head may be adjusted for coating shells
of various dimensions, and auxiliary attachments including
a movable spray head are used when it is required to cover
a large surface or to meet other special conditions.
MISCELLANEOUS TOOLS 161
Conveying Apparatus for Rapid Handling of Shells. -
For conveying shell forgings from one department to an-
other or from the shipping department to freight cars, etc.,
the Mathews Gravity Carrier Co. has designed conveying
apparatus as shown in Figs. 123 and 124, respectively. Fig.
123 shows this gravity carrier being used for transporting
forgings from a freight car to the machining department
of a plant, whereas Fig. 124 shows a special arrangement of
the carrier for handling shells that are boxed and ready for
shipment. In this case, the track part, which extends into
Fig. 124. Mathews Gravity Carrier with Elevator Unit
loading Freight Car
the shipping room, is about two feet above the floor level
and the inclined elevator arrangement lifts the boxes so that
they are located in the car four feet above the floor level.
The idea of elevating the boxes is to have them within con-
venient reach of the shipper. The elevator is not necessary
where the floor of the car is on the same level as the floor of
the building.
The chief advantage of this conveying apparatus is that it
is easily and quickly installed and is built up of separate
units so that it can be added to without any extra cost
except the cost for extra length of carriers and stands. The
162 MISCELLANEOUS TOOLS
rollers are made from seamless cold-drawn steel tubing and
run in ball bearings. The grade of the apparatus is from
2 to 3 per cent. Where it is necessary to lift the shells or
other parts being transported from a floor into a car, a por-
table elevator is used as shown in Fig. 124. This elevator is
driven by a one-horsepower motor and can be connected to .
a lamp socket. Another application of this system is where
the carrier arrangement comes to the end of the building and
it is necessary to return the work; to accomplish this, a
double-deck arrangement is provided, the lower deck inclin-
ing one way and the upper deck the other way. Thus
when the shells or work come to the end of the line, they are
simply placed on the upper deck and are returned to the
next series of machining operations, without any handling
whatsoever. Another advantage of this system is that the
shells or work do not need to touch the floor at all, and, con-
sequently, expensive cement floors are not broken up by hav-
ing heavy work dropped on them. Lifting the work off the
carrier is also more convenient than lifting it from the floor.
The important feature of the Mathews gravity roller car-
riers is that gravity takes the place of other power con-
veyors, except where additional elevations are necessary
or where shells, forgings, and boxes must be elevated to
upper floors. For this work, the Mathews Gravity Carrier
Co. makes automatic-incline or straight-lift elevators,
which require only a very small motor.
CHAPTER IX
BRITISH HIGH-EXPLOSIVE DETONATING FUSE
THE British high-explosive shell described in connection
with Fig. 3 carries a nose fuse of the concussion type, also
shown in Fig. 9, which is made chiefly from brass parts
with the exception of the adapter B, Fig. 125, and the
gaine, which are made of soft steel. The body of the fuse,
shown completely machined at D, Fig. 126, and at C and D,
Fig. 127, is first cast in a sand mold in the form of a slug,
Fig. 125.
British No. 100 Graze High-explosive Fuse dismantled
and assembled
as shown at A, Fig. 126. The composition from which this
slug is made is about 59.18 per cent copper, 39.45 per cent
zinc, 0.88 per cent manganese copper and 0.49 per cent phos-
phor-copper, this having been found to give the tensile
strength required by the specifications t
The first operation consists in snagging and brushing the
castings with a wire brush, but experiments are being made
to force the casting through a simple die that shaves off
163
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166 DETONATING FUSES
the straight surface and removes all objectionable projec-
tions. After casting, the slugs are sand-blasted, or other-
wise cleaned, and are then placed in the Stewart furnace
shown in Fig. 128, where they are heated to 1600 degrees
F. (about 870 degrees C.). The ovens of these Stewart
gas furnaces are double ended, and a Zeh & Hahnemann
percussion press, Fig. 129, is located at one end of the fur-
nace. Three men are required for each forging press ; one
loads the furnace from the rear, another takes the heated
forgings out of the front end of the furnace, puts them in
the die, and trips the press, and the third removes them
from the dies. After the slugs have reached a temperature
of 1600 degrees F., they are removed from the furnace and
^ ^ ^5i^
Fig. 126. Sequence of Operations on Body of British No. 100 Graze
High-explosive Fuse
placed in the dies shown in Fig. 130, and in Fig. 131 removed
from the press. The furnace shown in Fig. 128 holds
forty-eight slugs, and from 1400 to 1500 forgings are secured
from each press in a day of 9% hours. The ideal forging
obtained from the dies is one in which there is 3/64 inch of
material to remove all around. The dies shown in Figs.
130 and 131 are kept flushed with a compound consisting
of 64 per cent oil, 32 per cent water, 3 per cent powdered
graphite, and 1 per cent soda ash. The order in which
these operations are accomplished, as well as the machines
used, spindle speeds, and the production obtained, are given
in Table V.
First Machining Operation on Fuse Body. For the first
machining operation, the brass body is held in an air chuck,
*J.
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168 DETONATING FUSES
Second Machining Operation on Fuse Body. The second
machining operation on the fuse body consists in finishing
the taper end. The threaded end, as shown in Fig. 133, is
gripped in an air chuck and the following operations per-
formed: Face with cross-slide tool G, center with tool A,
drill and rough-turn with tool B, rough-counterbore with
tool C, recess with tool D, drill with tool E, tap with tool F,
and shave angle on body with shaving tool H held on rear
of cross-slide.
Drilling Operations on Fuse Body. Following the ma-
chining operations just described, the fuse body passes
Fig. 128. Stewart Gas Furnace used for heating Castings pre-
vious to hot-pressing
through drilling, counterboring, and tapping operations,
which are performed on Leland-Gifford drilling machines.
Fig. 127 gives the sequence of these operations.
The first drilling operation on the machined body consists
in drilling the cap set-screw hole a, drilling and counter-
boring the centrifugal bolt hole b, and drilling the adapter
set-screw hole c. For this operation, a three-spindle drill-
ing machine is employed. The four operations are per-
formed on the three-spindle machine because the cap set-
screw hole a and the adapter set-screw hole c are the same
diameter, and, therefore, machined by the same drill.
DETONATING FUSES
169
The second set of drilling operations is drilling the de-
tent spring hole d with a drill in one spindle of a three-
spindle drilling machine. The second spindle carries a
Fig. 129. Zeh & Hahnemann Percussion Press used in hot-
pressing Fuse Bodies
counterboring tool that squares the bottom of the hole, and
the third spindle carries a counterboring tool.
The third set of drilling operations is the drilling of the
170 DETONATING FUSES
hole for the reception of the detent. This is performed on
a two-spindle drill press, each spindle carrying the same size
drill, except that one is much longer than the other. The
longer of the two drills is used with a special fixture for
l
Fig. 130. Close View of Percussion Press shown in Fig. 129 snow-
ing Dies used and Casting before and after forging
Fig. 131. Upper and Lower Dies used in Press shown in Fig. 129.
drilling two-thirds of the detent hole e from the bottom side.
The hole is completed by drilling from the top, using a
second fixture and the short drill in the second spindle of
the machine.
DETONATING FUSES
171
The fourth set of drilling operations is performed on a
three-spindle drilling machine. The first spindle carries a
Fig. 132. Set-up on Warner & Swasey Brass- working Lathe for
performing First Series of Machining Operations on Fuse Body
Fig. 133. Set-up on Warner & Swasey Brass-working Lathe for
performing Second Series of Operations on Fuse Body
drill for drilling the central percussion pellet hole /, Fig.
127; the second spindle carries a counterboring tool; the
third spindle carries a bottoming tool.
172
DETONATING FUSES
The seventh operation on the fuse body is the milling of
the oval wrench hole g. This is done in a single-spindle
drilling machine, the work being held in a special fixture
so that it may be moved backward and forward slightly
to produce the oval hole required. The eighth operation
Fig. 134.
Set-up on No. 55 Acme Multiple-spindle Automatic
Screw Machine for machining Fuse Cap
is the recessing of the percussion pellet hole h for the thread.
A single-spindle drilling machine, equipped with a special
fixture to provide for under-cutting, is used. The ninth set
of operations consists in slightly countersinking or burring
all of the holes. This is done with a large countersink in
a single-spindle drilling machine, the fuse bodies being held
DETONATING FUSES 173
by hand against the countersink. The tenth and last set of
operations consists in tapping five holes, namely, the set-
screw holes for the cap and adapter, the detent spring hole,
the centrifugal bolt hole and the percussion pellet hole.
Four separate machines are used for tapping, each of which
carries a tapping head.
Machining the Fuse Cap. The fuse cap C, Fig. 125, is
made from brass rod 1% inch in diameter in an Acme No. 55
multiple-spindle screw machine, as shown in Fig. 134. The
order of operations is : Form and center, drill, bottom, and
Fig. 135. Grant Riveting Machines used in riveting Needle in
Percussion Needle Plug
neck, thread with button die, and cut off. The production
on this particular piece is given in Table V; after coming
from the screw machine it is put through a chip separator
where the oil and chips are separated. The next operation is
drilling the two wrench holes, which is handled on a single-
spindle drilling machine, the jig being shifted on the table
to drill the two holes.
Operations on Graze Pellet. The graze pellet D, Fig.
125, is made from 9/16-inch brass rod in a No. 52 National-
Acme multiple-spindle automatic screw machine. The op-
erations are as follows : Turn full diameter and also 0.370
diameter with a double tool, also drill and start neck, recess
174
DETONATING FUSES 175
and continue neck, tap and finish neck, cut off. The piece
is finished on leaving the screw machine. The production
is given in Table V, which also includes a complete sum-
mary of the operations performed on the various parts of
this fuse.
There are two drilling operations on the graze pellet.
The first consists in drilling the small fire hole through
the entire length of the piece. This is done in a single-
spindle drilling machine and is followed by the operations
on the upper end of the piece, where the detonating cap
is held. The operations on this end are performed in a
three-spindle drilling machine ; the first spindle carries the
drill for producing the large hole, the second carries a coun-
terboring tool and the third a facing tool for the bottom of
the hole.
Operations on Centrifugal Bolt and Plugs. The centri-
fugal bolt E, Fig. 125, is made from brass rod, the opera-
tions consisting merely in shaving and cutting off. The
percussion detent plug G and the percussion needle plug H
are also simple screw machine jobs. The needles are made
of steel and are swaged down to a fine point and then hard-
ened. The spinning in place of the needle point is done on
the Grant rivet spinning machines shown in Fig. 135, on
which a simple fixture shown by the diagram Fig. 136 is
employed. Two girls are employed on this work; one in-
serts the needles A in plate B, and the plugs C in plate D,
and the other operates the machine. The holes in the top
plate are large enough to allow the needles to drop through
freely and enter the plugs; then the top plate is removed
and the fixture placed on the table of the spinning machine.
The spinning rolls are brought down in contact with the
plugs consecutively and spin in the edge, holding the needles
firmly in place. The plugs are prevented from rotating
by steel inserts that are knurled on their top faces. Loca-
tion of the various holes under the spinning machine is ac-
complished as shown in the plan view, Fig. 136.
The operations on the percussion detonator plug are per-
formed on a single-spindle drilling machine, and consist in
drilling the two small holes with the aid of a swivel jig.
176
DETONATING FUSES
The four small fire holes in the percussion needle plug are
drilled after the needle has been swaged in place. The drill-
ing operation is left until last, as otherwise the swaging
operation would close up the fire holes.
Machining Operations on Percussion Pellet. The percus-
sion pellet /, Fig. 125, is made from 11/32-inch diameter
brass rods in a multiple-spindle automatic screw machine.
The operation consists in turning with a box-tool, chamfer-
ing and squaring the threaded end, also drilling the hole
and squaring the bottom, recessing, tapping, and drilling
the small hole and cutting off. The hole in the opposite
Fig. 137. Baking Varnish on High-explosive Shell Fuses
end of the percussion pellet and the one in the side are
drilled in a three-spindle drilling machine. The same size
drill is used for drilling the large cross-hole and the end
hole. This drill is held in the first spindle, and a smaller
drill, held in the second spindle, drills the small cross-hole,
whereas the third spindle carries a taper reamer for taper-
ing the large cross-hole.
Operations on Top and Bottom Detents. The bottom
and top detents F and L, respectively, Fig. 125, are made
with a simple tool equipment. The top detent L is made
DETONATING FUSES
177
from 5/32-inch bronze rod in a screw machine, whereas the
bottom detent F is made from brass rod 7/32-inch in diameter
in a screw machine. The operations on the top detent are :
Rough-turn and form head, finish-turn and chamfer, shave
from head to point, and cut off. The operations on the bot-
tom detent are : Form and center, drill, form hole, and cut
off.
Operations on Adapter. The adapter shown at B, Fig.
125, is produced in three operations, the first being per-
1ST OPERATION
FORMING TOOL A
3BD OPERATION
DRILL SMALL HOLE
Machinery
Fig. 138. Diagram illustrating Sequence of Operations on Galne
formed on an Acme No. 55 multiple-spindle automatic screw
machine. The first series of operations is as follows:
Rough-form and drill, shave and counterbore, thread outside
diameter, and cut off. The second series of operations, per-
formed on a Cleveland automatic screw machine provided
with a magazine attachment is : Counterbore, tap, and drill.
The third operation, performed in a Leland-Gifford drilling
machine, consists in drilling the two small holes. The other
small parts, such as screws, etc., are regular screw machine
jobs and are simple to manufacture.
178
DETONATING FUSES
Assembling. The assembling is done in the following
order: The percussion pellet, spring, and detonator plug
are inserted in the cross-hole; the graze pellet is dropped
into place ; the centrifugal bolt and screw are inserted from
the side; the combined detent, spring, and screw plug are
inserted from the base; the creeper spring is put in from
the top and the cap screwed in place. The set-screw for
the cap and the adapter are then inserted and the gaine is
screwed in. The lacquering of the completed fuse is done
by spraying, and the lacquered fuses are baked in a rotat-
ing oven, shown in Fig. 137, until the varnish is dry.
XS)
ASSEMBLY OF GAINE
12 T.P.I. R.H.
Machinery
Fig. 139. Assembly and Details of Gaine used in British No. 100
Graze High-explosive Shell Fuse
This oven has six shelves that work on the principle of a
Ferris wheel.
Machining British High-explosive Fuse Gaine Parts.
The gaine that forms the exploder member of the British
No. 100 graze fuse shown in Fig. 9 is shown assembled and
in detail in Fig. 139. As shown, the gaine comprises three
parts, viz., body A, center plug B, and closing or bottom
plug C. The body A of the gaine is made from cold-rolled
steel, and in one plant the first operation is handled in a
DETONATING FUSES 179
No. 53 Acme multiple-spindle automatic in the order shown
in Fig. 138. The order of machining operations performed
at the first chucking is shown from A to C inclusive, and
is as follows: First position, drill large hole one-third
depth, using floating drill-holder, and form the thread
diameter from cross-slide ; second, drill large hole to shoul-
der ; third, drill small hole ; fourth, cut off. In the drilling,
a stepped lead cam is used so that the drills can be backed
out to clean out the chips and assist the lubricant in getting
to the cutting points of the drills. The outer surface of the
gaine is not finished and the holes are not reamed. The
cutting speed is 100 surface feet per minute, and the produc-
tion is sixty per hour.
The second series of operations, shown in Fig. 138, is per-
formed on a No. 2 plain-head Warner & Swasey turret lathe,
as follows: First, ream the four diameters of the hole
with a stepped reamer; second, under-cut at the bottom of
the two threaded sections, this is done with a tool having
two cutting points properly spaced ; third, tap the two holes
with a double-threaded tap. The production is thirty pieces
per hour and the cutting speed, except for the tapping, is
100 surface feet per minute.
The third series of operations, shown to the right in Fig.
138, is performed on a No. 2 plain-head Warner & Swasey
turret lathe, and the piece is held with the threaded end
outward. The operations are: First, center; second, drill
large hole; third, form bottom of hole; fourth, drill small
hole with a high-speed drilling attachment; fifth, thread
external diameter with a self-opening die. The cutting
speeds on this operation are 100 surface feet per minute
and the production is thirty pieces per hour. In the plant
where this information was obtained, considerable trouble
was experienced in drilling the small hole. Attempts were
made to produce this hole in a high-speed drilling ma-
chine, with poor results. The method shown at / is recom-
mended as being more satisfactory, as in this case both
work and drill revolve.
Machining the Center Plug. The center plug B, Fig.
139, is made from hot-rolled machine steel and is completed
180 DETONATING FUSES
in two operations. The first series of operations is per-
formed on a No. 53 Acme multiple-spindle automatic. The
operations are : Form the entire length of the piece and drill
small hole, shave outside diameter and square bottom of
hole, thread, and cut off. The second series of operations
is performed on a No. 2 plain-head Warner & Swasey turret
lathe in the following order: Center drill, drill, form hole
with special counterboring tool, and face end with tool on
rear cross-slide. These pieces are handled at the rate of
forty-five per hour. The work on this piece is completed by
a simple slotting operation on an Acme screw slotter. The
machining of the bottom plug C is performed on a No. 53
Acme multiple-spindle automatic. This part is made of
cold-rolled steel and turned at a speed of 100 surface feet
per minute. The order of operations is: Form external
diameter, face end, thread, and cut off. This piece is pro-
duced at the rate of 180 per hour. The drilling of the two
holes in the end of this plug is performed in a drilling ma-
chine with the aid of a simple jig.
CHAPTER X
HIGH-EXPLOSIVE CARTRIDGE CASE MANUFACTURE
THE cartridge case used in the British, 18-pound, quick-
firing, field gun is made from an alloy of copper and zinc,
generally 70 per cent electrolytic copper and 30 per cent
zinc. The exact composition of the alloy is left to the dis-
cretion of the manufacturer, but the completed cartridge
case must have the required strength and elasticity. The
number of redrawing and annealing operations on the case
is never less than six, while two tapering operations must
also be performed to bring the mouth of the shell to the cor-
rect diameter and the body to the right shape. The prac-
tice followed in plants making this case does not differ ma-
terially in regard to the number of drawing operations, but
there is some difference in the methods used in handling
the work. The following description covers the method
used by a large concern that turns out 4000 18-pound cart-
ridge cases per day of ten hours.
Blanking and Cupping. The first operation on the cart-
ridge case is to cut out a blank 6.22 inches in diameter from
a sheet 0.380 inch thick. This operation is seldom handled
by the firm making the cartridge cases, most firms prefer-
ring to buy the blanks from manufacturers that make a spe-
cialty of this business. The blank is usually cut out in a
geared punch press at the rate of about 400 blanks per hour.
Usually the blank is in the annealed condition when received
by the cartridge case manufacturer. Assuming that the
blank is purchased in the annealed condition, the first opera-
tion is cupping. In the plant where the following data
was obtained, this operation is performed in a Toledo press,
as shown in Fig. 140. One operator can turn out 4000 cups
in ten hours. On this operation, a production as high as
600 per hour can be obtained, but this pace cannot be kept
181
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183
184
CARTRIDGE CASE MANUFACTURE
up by one man. The shape and size of the cup after the
cupping operation is shown at B, Fig. 143. Table VI gives
the complete order of operations.
Annealing. Following the cupping operation, the metal
is hardened somewhat and, consequently, annealing is neces-
sary to restore the required ductility. The hardness of the
metal is also tested by means of the scleroscope after each
press and annealing operation, and in this plant one per
cent of the daily production is given this test. The anneal-
Fig. 140. First Operation Cupping in a Toledo Press
ing is done in a special furnace, shown in Fig. 141, which
is about 6 feet wide by 24 feet long. The cases are loaded
into trays and fed into the furnace at the loading end by
a ram operated by compressed air. These trays hold, on
an average, fifty-six cups, the number depending on the
diameter of the case, and each furnace holds eight trays.
The furnaces are kept at a constant temperature of 1250
degrees F. (about 680 degrees C.), and the cups are an-
nealed for one hour and four minutes at this temperature.
This is the average length of time that each tray is allowed
CARTRIDGE CASE MANUFACTURE
185
to remain in the furnace, but the loading and unloading is
carried on every eight minutes. As soon as the cups are
removed from the furnace they are immersed in water.
There are six pyrometers in each furnace for controlling the
temperature, three on each side ; these pyrometers are tested
every fifteen minutes, as shown in Fig. 142, so that any
variation in the temperature of the furnaces can be imme-
diately checked up. After cooling in water, the cups are
placed in a pickling bath, which consists of twenty parts
water to one part sulphuric acid. When removed from this,
Fig. 141. Annealing Cartridge Cases
they are immersed in a high caustic soda bath, and are then
washed in warm water to remove all traces of the acid.
All firms engaged in this work, however, do not follow
this procedure in cooling and washing. One concern be-
lieves that the rapid cooling of the cases in water affects
their physical properties, and, hence, allows the cases to cool
off in the air after each annealing operation. When cool,
the cases are immersed in a bath containing a weak solution
of sulphuric acid and then in a weak bath of cyanide of
potassium, after which they are rinsed in water.
186
CARTRIDGE CASE MANUFACTURE
First and Second Redrawing and Indenting Operations.
Following the cleaning of the cups, they are taken to an-
other Toledo press, shown in Fig. 145, where the first re-
drawing operation is accomplished. For this, one machine
and two men are required for a production of 400 per hour.
It will be noticed in Fig. 143, at C, that the thickness of the
bottom of the case remains the same, the sides alone being
reduced in thickness and increased in length ; it is important
that this thickness at the base is retained. After this, the
Fig. 142.
Recording Instruments used in checking up Temperature
of Annealing Furnaces
cases are annealed, washed, etc., as before. The only dif-
ference here is that the pan holds sixty-three instead of
fifty-six cases, due to the smaller diameter of the cases.
The second redrawing operation D, Fig. 143, is accom-
plished in the same manner as the first, and the produc-
tion is also the same, 400 per hour, two operators being
required. Following the second redrawing operation, the
cups are taken directly to the first indenting operation, the
result of which is shown at E, Fig. 143. This operation is
accomplished in the Toledo press shown in Fig. 146. It will
CARTRIDGE CASE MANUFACTURE
187
be noticed that for indenting the case is placed on the lower
punch A. Upon the descent of punch B, the lower punch
is forced down into the die, exposing the indenting punch
that is located inside of it. The case also goes down into
the die and consequently is prevented from being distorted.
Upon the up-stroke, the case is ejected from the die by the
^
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G 4TH REDRAW
Jfa
Fig. 143. Sequence of Operations on British 18-pound
High-explosive Shell Cartridge Case
double action of the press, and to provide against any
chances of its sticking on the punch B, an ejector C is pro-
vided. In this operation, only one operator is required and
the production is 300 per hour. The important point to
observe in this case is the depth of the indent E, Fig. 143,
which must be 7/16 inch. Following indenting, the cases
are again annealed, each pan holding sixty-eight cases.
188
CARTRIDGE CASE MANUFACTURE
1
32
2ND INDENT
H
-
f>T
1
L HEAD
I STH REDRAW
< --- -B.ZO - ^ 11 58- ' *!
M COMPLETED CARTRIDGE CASE ' Machinery
Fig. 144. Sequence of Operations on British 18-pound High-explosive
Shell Cartridge Case Continued (Thickness of Walls Slightly
Exaggerated)
Third and Fourth Redrawing and Second Indenting Oper-
ations. The third redrawing operation is accomplished
in a No. 57 Toledo press, as shown in Fig. 147. The pro-
CARTRIDGE CASE MANUFACTURE
189
duction on this operation is 200 cases per hour and the case
is drawn out to the length shown at F, Fig. 143, and also
reduced slightly in diameter. Two operators are required
for this operation. After redrawing, the case is annealed,
washed, etc., as before. The annealing pans accommodate
seventy-two cases each.
Fig. 145.
First Redrawing Operation performed on a Toledo No. 59
Press
The fourth redrawing operation is accomplished in a No.
857 Toledo press ; the production is 150 cases per hour, and
two operators are required. The result of this operation is
shown at G, Fig. 143. Following the fourth redrawing op-
eration, the cartridge case is given the second indent, as
shown in Fig. 148. Reference to H, Fig. 144, will show that
the head of the case is somewhat flattened in this operation,
190
CARTRIDGE CASE MANUFACTURE
leaving a projection raised around the outer rim. The
depth from the flat surface of the head to the bottom of the
indent is the most important dimension; this depth on the
18-pound cartridge case must be 17/32 inch. The produc-
tion at this operation, two operators being employed, is 250
cases per hour. Following the second indent, the cases are
again annealed, washed, etc. The pans, in this case, carry
Fig. 146. First Indent on a Toledo Press
seventy-eight cases because of the reduced diameter. The
presses used in performing the cupping, redrawing, reduc-
ing, and heading operations vary in ram capacity from 500
to 1200 tons pressure per square inch.
Fifth and Sixth Redrawing and Second Trimming Oper-
ations. Following the second indent, the fifth redrawing
operation is accomplished in a No. 857 Toledo press; the
production being 150 per hour. The condition of the case
CARTRIDGE CASE MANUFACTURE
191
after this operation is shown at I, Fig. 144. Before anneal-
ing, the mouth end of the case is trimmed because the case
becomes quite ragged on the mouth end and would tear in
the sixth redrawing operation if the excess stock were not
removed. The total length of the case after the fifth re-
drawing operation averages 10% inches and it is trimmed
to lOi/2 inches. In
many cases, as the
punch wears small, it
is not necessary to per-
form this trimming
operation because the
wall is thicker. The
shape of the simple
disk cutter is shown in
Fig. 149, and the
method of trimming
the mouth of the case
in the Toledo trim-
ming machine is
shown in Fig. 150.
Two operators are
necessary for this
trimming operation ;
one holds the case on
the arbor and the
other does the trim-
ming; the production
is 350 per hour. Some
changes have been
made in this machine.
The regular cutter
head has been removed and a cross-slide substituted. This
cross-slide is operated by a lever, as shown, and carries a
toolpost to which a circular friction disk cutter A is held.
After trimming, the cases are annealed, each pan holding
eighty-eight cases.
The sixth redrawing operation is performed on a Toledo
Fig. 147. Third Redrawing Operation on a
Toledo No. 57 Press
192
CARTRIDGE CASE MANUFACTURE
No. 856 press. The case, at this operation, is quite long
so that the production is reduced to 120 per hour, with two
operators. In this operation, the important dimension is
the thickness of the wall at the mouth ; this should be 0.0285
inch. Following this redrawing operation, the case is
again trimmed, as shown in Figs. 149 and 150. The pro-
Fig. 148. Second Indenting Operation on a Toledo Press
duction on the trimming machine is 350 cases per hour.
Heading. After the sixth redrawing and trimming op-
erations, the cartridge case is taken directly to the Toledo
heading press, shown in Fig. 151. The operation of this
press is as follows: An indexing fixture fastened to the
ram of the press carries two heading punches, one being
used for forming the primer pocket and the other for flat-
CARTRIDGE CASE MANUFACTURE
193
Fig. 149. Close View of Cartridge Case Trimming Machine shown
in Fig. 150
Fig. 150. Trimming Mouth End of Case on a Toledo Cartridge
Case Trimming Machine
194
CARTRIDGE CASE MANUFACTURE
tening out the head. The heading die-holder retained on
the bed of the press is also of the indexing type. The die-
holder C carries two similar shaped heading dies A and Z>,
each of which carries a bottom plug, or support, for the
cartridge case. Assuming that both dies A and D are
empty, the cartridge case is placed over the plug in the die,
then the turret die-
holder C is indexed,
bringing the loaded
die in line with the
punches. Next, punch
B is indexed in line
with the cartridge
case; after this, the
press is operated and
the first blow deliv-
ered. The die-holder
now remains station-
ary and the punch-
holder is indexed to
bring the flattening
punch in line, after
which the press is
again operated and
the second blow deliv-
ered. An unheaded
case is now loaded in
the empty die, and the
die turret indexed ;
this brings the un-
headed case in line with the ram, and the headed case in
line with the pick-up E. The punch-holder is now indexed
to again bring the punch B in line, and the press operated.
While the blow is being delivered to the second case, the
headed case is removed from the die turret by pick-up E.
The production is 150 cases per hour.
Following heading, the mouth of the shell is annealed pre-
vious to the tapering operations that follow. The anneal-
Fig. 151.
Heading Cartridge Cases on a
Toledo Press
CARTRIDGE CASE MANUFACTURE 195
ing is accomplished as shown in Fig. 152. The machine
comprises a rotating table carrying twelve plates, which are
also rotated, upon which the cartridge cases are placed.
Twenty burners fed by natural gas are provided. The
large table makes one revolution in one minute and forty
seconds, but the cartridge cases are rotated continuously
and make thirty-three revolutions to each revolution of the
large table. The main rotating fixture carries a large spur
gear that meshes with small pinions fastened to the spindles
of the plates that carry the cases ; hence, as the large fixture
rotates, the plates carrying the cases are also rotated. One
Fig. 152. Annealing Mouth In a Special Furnace previous to
tapering
revolution of the large table anneals the mouth of the case
sufficiently for tapering. The annealing temperature at-
tained at this time is about 800 degrees F. (about 430 de-
grees C.), which is sufficient to heat the cartridge cases to
a cherry-red color. Prior to the tapering operations which
follow, the cases are washed in a 10 per cent caustic soda
and water solution.
Tapering. Following the annealing of the mouth of the
case, two tapering operations are performed, bringing the
case to the final shape shown at M, Fig. 144. These opera-
tions are performed in Toledo special tapering presses, which
are shown in Fig. 153. These machines differ from the or-
196
CARTRIDGE CASE MANUFACTURE
dinary punch press in that the stroke of the press is con-
trolled by an eccentric and link motion instead of by a com-
bined crank and toggle action. This mechanism is used
owing to the length of stroke necessary and because of the
fact that a press used for tapering does not need anywhere
Fig. 153. First and Second Tapering Operations on Special
"Toledo" Cartridge Case Tapering Machines
nearly the same strength and power as one that would be
used for heavy redrawing, embossing, or forming opera-
tions.
In the first tapering operations, the mouth of the case is
reduced to 3% inches in diameter and tapered for a distance
CARTRIDGE CASE MANUFACTURE
197
of 6 inches, the diameter at the termination of the taper
being 3% inches. Two men are employed for this opera-
tion and the production is 250 per hour. In the second tap-
ering, the mouth of the shell is made straight for one inch
and then tapered to the rim on the head at the rate of
0.04066 inch on the diameter for every inch in length. Two
men can produce 250 cases per hour on this operation.
Fig. 154. Machining Head and Mouth Ends of Case on a Bullard
Cartridge Case Trimming, Facing and Chamfering Machine
Machining Cartridge Cases. The cartridge case is not
finished complete in the punch press, but after tapering,
several operations are performed on the head and mouth,
and these are handled on the Bullard cartridge case trim-
ming, chamfering and facing machine shown in Fig. 154.
The operations are : Rough-bore primer pocket, face head
198
CARTRIDGE CASE MANUFACTURE
with facing tool, form with tool on rear of carriage, recess
at bottom of primer pocket, tap with Murchey tap, four
threads per inch, ream with a combination reamer, and turn
and trim open end.
Inspecting and Testing. The cartridge case is now
turned over to the inspectors, when the following gaging
?
1
1 I
j !
(
Machinery
Fig. 155. Diagram showing Application of Various Gages used in
inspecting 18-pound British Cartridge Cases
tests are made: First, gage for thickness of head; second,
for tapers ; third, over-all length ; fourth, thickness through
primer hole; fifth, primer hole diameter; sixth, root of
thread ; seventh, lower rim ; eighth, thickness of head ; ninth,
thickness of head flange ; tenth, diameter of counterbore at
extreme head of case; eleventh, recess in pocket; twelfth,
threads ; and thirteenth, gun barrel test.
CARTRIDGE CASE MANUFACTURE 199
Fig. 156. Gaging Thickness of Head of Cartridge Case
Fig. 157. Testing Taper of Cartridge Case with Horseshoe Gages
200 CARTRIDGE CASE MANUFACTURE
The manner in which these inspection operations are
handled is shown diagrammatically in Figs. 155 and 162 and
in Figs. 156 to 161, inclusive. The first test that is made
is for the thickness of the head, measuring from the inside.
This is accomplished as shown in Fig. 156, and diagramma-
tically at A, Fig. 155. The cartridge case is held on a post
a, and the swinging arm b that rests on the shoulder of an-
other post c carries two gaging points d and e, one being
set for the maximum and the other for the minimum dimen-
sions. A limit of 0.002 inch is allowed.
Fig. 158. Gaging Over-all Length of Case
Gaging for taper is accomplished by means of horseshoe
gages, as shown in Fig. 157, and diagrammatically at B, Fig.
155. The upper gage i measures at a point 8.25 plus 0.000,
minus 0.005 inch from the head and the lower gage j at a
point 3.428 plus 0.000, minus 0.002 inch from the head.
The limit, as shown at B, is 0.002 inch for the smaller diame-
ter, whereas the larger diameter has a limit of 0.005 inch.
The third test is for over-all length, as shown in Fig. 158,
and at C, Fig. 155. Here the case is held on a baseplate
CARTRIDGE CASE MANUFACTURE
201
/ and the gaging bar g is held on a standard h, a limit of
0.040 inch being allowed on the length.
The test shown in Fig. 159 and at D, Fig. 155,
Fig. 159.
Gaging Thickness of Flange and Thickness through
Primer Hole
Fig. 160. Gaging Diameter of Head and Depth of Counterbore
is gaging the thickness from the head of the case to the
inner face of the pocket. The allowable limit here is 0.010
inch. First, the clearance hole in the primer pocket is gaged
202
CARTRIDGE CASE MANUFACTURE
as shown atE, Fig. 155; afterwards, the root diameter of the
threaded hole is tested, as shown at F. Following this, the
diameter of the head of the case is tested, as shown to the
right in Fig. 160, and at G, Fig. 155. Here the head is
gaged at three points, the limits being as shown at G.
Fig. 161. Making Gun Barrel Test
The final gaging operations are shown at H, I, and J,
Fig. 155, and in Figs. 161 and 162. The thickness of the
head is gaged as shown at H and /, and also to the right
in Fig. 159. The gage used is of the double-ended type, so
that the two thicknesses can be measured with one gage.
The next test is to gage the diameter of the counterbore in
the head of the cartridge case as shown at /. Following
this, the last and final test is made ; this is the gun barrel
CARTRIDGE CASE MANUFACTURE
203
test shown in Figs. 161 and 162. This gage comprises a cylin-
drical cast-iron tube, which is machined inside to the same
dimensions as the bore of the barrel, as shown in Fig. 162, and
TABLE VII. SCLEROSCOPE READINGS INDICATING HARD-
NESS OF METAL AFTER EACH ANNEALING AND
REDRAWING OPERATION
C
A
J
7
on
i
r
i
I
i .
BL
1 )
-^/
MMK
3/
\^ 777? \
p-i?|
i -
r"
3-
^ J
?\
^ \\
1ST INDENT
1
y
COMPLETED CASE
Operation
Time
Points i
it which Readings are Taken
of
OI
Test
7
1
2
3
4 1
5
6
8
9
10
11
Blanking
A*
15
14
14
14
15
14
Cupping
B
20
26
31
19
50
46
Annealed
A
12
12
12
11
13
12
First Redrawing
B
11
13
19
14
36
50
Annealed
A
12
12
12
11
12
11
Second Redrawing
B
12
10
12
36
50
50
First Indenting
B
34
35
22
44
44
46
Annealed
A
11
11
11
15
14
14
Third Redrawing
B
11
12
12
\
\
\ \
36
41
48
\\
' \
Annealed
A
10
11
12
12
14
15
Fourth Redrawing
B
11
11
12
\
31
38
44
Second Indenting
B
12
26
34
t
.
34
51
51
Annealed
A
10
11
12
12
14
14
Fifth Redrawing
B
14
12
15
(
32
35
41
41
Annealed
A
11
13
14
t
t
15
11
14
15
Sixth Redrawing
B
13
20
15
.
,
, ,
22
30
31
41
42
Heading
16
38
47
.
.
,
28
32
33
44
45
Mouth Anneal
16
38
46
26
30
31
22
12
Second Taper
16
37
46
,
35
38
44
36
59
Machinery
Note: "A" is scleroscope reading before, and "B" after annealing.
two supporting stands. The cartridge case is pushed into this
gage, and by laying a scale across the gage, the head of the
cartridge case must come slightly below flush. The case should
be easily inserted and extracted from this gage.
204
CARTRIDGE CASE MANUFACTURE
Testing Cartridge Cases for Hardness. In order that
the final product will be according to specifications, each
drawing and annealing operation must be carefully fol-
lowed. The method generally adopted by various manufac-
turers engaged in this work is to use the scleroscope and
test the hardness of the case before and after each redraw-
ing or annealing operation. Table VII gives the readings
taken on the cartridge case after each operation, and the
diagram with this table shows the points at which the read-
ings are taken. It is the practice of this plant to "sclero-
scope" 1 per cent of its daily product ; therefore, on a prod-
uct of 4000 cartridge cases in ten hours, forty cases, after
Machinery
Fig. 162. Diagram showing Gage used for Gun Barrel Test
the completion of each operation, as shown in Fig. 163, are
taken to the testing department where scleroscope readings
are taken. These readings are then charted and compared
with other tests.
Making Primers for Cartridge Cases. The percussion
primer, carried in the head end of the cartridge case and
used for igniting the propelling charge, comprises six parts,
as shown in Fig. 164. Of these, the body A is the most dif-
ficult to make. This is made from 1 7/16-inch round bar
stock, either in a hand or automatic screw machine. In
one plant turning these parts out in large quantities, a Grid-
ley 1%-inch multiple-spindle automatic screw machine, as
CARTRIDGE CASE MANUFACTURE
205
shown in Fig. 165, is used for performing the first series
of operations. The order of operations is as follows : Rough-
counterbore and form, drill and countersink, thread exter-
nal diameter, and finish-ream, cut off, and feed stock. The
spindles of the machine are rotated so as to give a speed
of 90 surface feet for the forming cut. The production is
eighty per hour.
The second operation on the body consists in facing and
shaving the head ; this is done on a hand screw machine of
the Pratt & Whitney type. The work is rotated to give a
Fig. 163. Testing Hardness of Cartridge Case with Scleroscope
surface speed of 125 feet per minute, and the production
is 250 per hour. The third operation is milling the key
slots in the base in a Brown & Sharpe hand milling machine,
using a simple indexing fixture. The end-mill used is op-
erated at 200 feet surface speed, and one cut finishes each
slot. The production is 140 per hour. The fourth opera-
tion, reaming the tap hole and the smaller hole in the base
of the body, is done in a Henry & Wright two-spindle drill-
ing machine carrying a combination reamer. The work
is held in a fixture that can be slid along the table, being
controlled in its movement by guide strips fastened to the
206
CARTRIDGE CASE MANUFACTURE
-PAPER DISK SECURED WITH PETTMAN CEMENT
OUTSIDE TO BE COATED WITH A THIN LAYER
PAPER DISK SECURED WITH PETTMAN CEMENT
COATED WITH PETTMAN CEMENT UNDER TURNOVER
SLOTS TO BE CUT BY SHEARING OR
IF SAWED, NOT TO EXCEED 0.011
CLOSING DISK-BRASS
Machinery
Fig. 164. Assembly View and Details of British Cartridge Case Primer
CARTRIDGE CASE MANUFACTURE 207
table. Two tools are used, one for roughing and the other
for finishing, the surface speed being about 200 feet. The
production on this operation is about 150 per hour.
The fifth operation is to tap the small hole in a tapping
machine with a tap operating at a surface speed of 30 feet
per minute. The work is held in a jig and the production
is 120 per hour. The sixth operation is to finish-ream the
percussion cap hole in a Henry & Wright drilling machine.
This is a very difficult operation to accomplish because the
Fig. 165. Machining Cartridge Case Primer Body on a Gridley
1%-inch Automatic
accuracy required is 0.0005 inch. The surface speed of
the tool has to be cut down to 80 feet; and the production
is 100 per hour. The seventh operation is to stamp the
required letters on the base of the primer with a hand
stamp, three sets of stamps being required. The produc-
tion is 150 per hour. The eighth is to lacquer the exterior
with a brush. The lacquer used consists of: Seedlac, 10.54
per cent; turmeric, 5.26 per cent; spirits, methylated, 84.2
per cent. This is done at the rate of 200 per hour. The
ninth operation is inspecting.
208
CARTRIDGE CASE MANUFACTURE
Making the Disk. The closing disk B, Fig. 164, for the
primer is made from 1-inch diameter brass rod in a 11,4-inch
Gridley multiple-spindle automatic screw machine. The or-
der of operations is as follows : Form and cup, shave, finish
cup, and cut off and feed stock. The stock is operated at a
surface speed of 110 feet, and the production is at the rate
Fig. 166.
Slotting Anvils in a National-Acme Screw Slotting
Machine
of 20 seconds a piece. The second operation is to remove
the burrs on a small stand grinder. The third operation
is to slit and straighten in a small Brown-Boggs punch
press. The fourth is to inspect.
Making the Anvil. The anvil C, Fig. 164, is made on a
No. 00 Brown & Sharpe automatic screw machine from
%-inch round bar stock. The order of operations is : Feed
CARTRIDGE CASE MANUFACTURE
209
stock to stop, form and bore, ream small hole, thread and
cut off, burr in the burring attachment. The stock is ro-
tated at 2400 R. P. M. for forming and at 2400 R. P. M. for
threading. The production is 400 per hour. The second
operation is slotting, which is accomplished in a National-
Acme screw slotting machine as shown in Fig. 166 ; the pro-
duction is about 800 per hour. The third operation is drill-
ing, which is accomplished in a Leland-Gifford high-speed
drilling machine as shown in Fig. 167. The drill used is
size No. 55 (0.052 inch) and is operated at 10,000 R. P. M.
An indexing fixture is used, and it requires three indexes
to complete the drill-
ing. The production
is 400 per hour. The
fourth operation is in-
specting.
Making the Plug
The plug D, Fig. 164,
is also made on a No.
00 Brown & Sharpe
automatic screw ma-
chine from %-inch
round bar stock. The
order of operations is :
Feed stock to stop,
form and groove,
thread, cut off, burr
with burring attachment. The spindle speed is 2400 R. P. M.
and the production is 600 per hour. The three fire holes are
also drilled in the Leland & Gifford high-speed drilling ma-
chine shown in Fig. 167, using an indexing attachment.
The drill is operated at 10,000 R. P. M., and 400 per hour
are turned out. A different jig is used for drilling the plug
from that used for the anvil. In the case of the plug, the
holes are drilled parallel with the axis, and in the anvil
at an angle of 26 degrees with the axis. The percussion
cap E, Fig. 164, is made in a small punch press in one oper-
ation, a combination blanking and cupping punch and die
Fig. 167. Drilling Fire-holes in Anvil In a
Leland-Gifford High-speed Drilling
Machine
210 CARTRIDGE CASE MANUFACTURE
being used. The soft copper ball G is a standard product
of the ball manufacturers.
Assembling and Loading. Up to the present time, few
of the manufacturers that have taken orders for primer
parts are assembling and loading them. This delicate and
somewhat dangerous operation is generally handled in the
government arsenals or in cartridge factories regularly de-
voted to this work. Manufacturers that have taken orders
for complete rounds of ammunition, however, may be called
upon to handle this work in the future. Before the primer
can be assembled, the copper cap E, Fig. 164, must be
charged. This is made on a double-action punch press, and
is blanked and cupped in one operation. After cupping, it
is cleaned, dried and then coated with a varnish containing
the following constituents: Finest orange shellac, 20 per
cent ; spirits (methylated) , 80 per cent. The next operation
is charging the cap with 1.2 grain of the following explo-
sive composition :
Parts (by
Constituents weight)
Sulphide of Antimony 18
Chlorate of Potash 12
Glass (ground)
Powder (mealed) 1
Sulphur 1
For charging, the caps are held on one plate, and a sec-
ond plate called a "charger," having the same number of
holes as the cap-plate, is located over the caps, and the ex-
plosive charge held in the plate is deposited in the cap.
The cap-plate is then taken to a fulminate pressing press,
where the charge in the cap is compressed by means of
punches under a pressure of 800 pounds. The next step is to
lacquer sheets of tin foil on one side with the following com-
position: Seedlac, 10.52 per cent; turmeric, 5.26 per cent;
spirits, methylated, 84.22 per cent. Disks are then cut out
from this tin foil and pressed into the cup under 400 pounds
pressure, the lacquered side outward. The primer cup is
then coated with the same varnish as that used on the cap
previous to charging. The cap is now coated externally
CARTRIDGE CASE MANUFACTURE 211
with Pettman's cement which is composed of the following
ingredients :
Ingredients Per Cent
Gum Shellac 18.18
Spirits, methylated 19.39
Tar, Stockholm 12.12
Red, Venetian 50.31
The primer is now ready for loading, and the first part
to be assembled is the cap E. Before this is placed in the
body A, however, the pocket in the latter is coated with Pett-
man's cement. The parts are then put in, in the following
order (see Fig. 164) : Cap E, anvil C, soft copper ball G,
and brass plug D. Plug D is locked in place by three small
punch blows, after which the fire holes are covered with a
paper disk / that is secured with Pettman's cement. The
primer cavity is now filled with R. F. G. 2 powder, and the
brass closing disk B, with paper disk H attached to the
inner surface by Pettman's cement, is then put in place.
This is finally held in place by spinning over the edge of the
primer body, as shown in Fig. 164. The last operation is
to coat the outer surface of disk B with Pettman's cement,
after which the primers can be turned over to the inspectors.
CHAPTER XI
MAKING CASES WITH BULLDOZERS AND PLANERS
THE manufacture of cartridge cases is usually carried on
by means of power presses of the crank and flywheel
type, but many manufacturers have had to resort to other
methods of handling the work. In one case, where car-shop
equipment is used for this work, all the cupping, redrawing,
and tapering operations are accomplished on bulldozers and
frog and switch planers which have been fitted up for this
purpose. The only special machine that had to be pur-
chased to complete the cartridge case, with the exception
of the machining operations, was a hydraulic heading press.
The order of cupping and redrawing operations is shown
in Fig. 168, and in Table VIII, which includes all the data-
machines used, production, scleroscope readings, etc.
Cupping. In this plant, the blank is obtained of the cor-
rect size and thickness, and in the annealed condition. The
first operation, therefore, is cupping, as shown at A, Fig.
168 and in Fig. 169. For this work, a Niles-Bement-Pond
bulldozer is used. The die is held on the cross-head and
the punch on a fixture attached to the bed of the machine.
This particular machine is fitted up for accomplishing both
the cupping and first redrawing operations, the punch shown
at A performing the cupping and that at B the first redraw-
ing. In this way, two men can operate the machine and
thus turn out a cup and perform the first redrawing opera-
tion at each stroke of the machine. A lubricant known as
"Viscosity" and made by the Cataract Refining Co. is used
for lubricating the die and punch.
Annealing. Following the cupping operation, the cases
are annealed in a Quigley oil furnace, as shown in Fig. 170.
The cases are held in a sheet-iron pan having a wire bottom
and are brought to the furnace on a truck, as shown, the
212
ill
tit
f
il
.1
IS
55O
:S
fa :
f| r ^
11
PQQ
214
M
8 g
O O O O
oo 00 GO 00
3
e e e e
X! rO -O
o" o~ o
OJ O* CQ
e~ e" e"
33
33
8 88
'5
^
II
PQ
215
216
CARTRIDGE CASES
to the right of the illustration. Here the pan is again picked
up by an air jack and dipped in the weak sulphuric acid solu-
tion used in removing the scale. Following this, the cases
are immersed in a hot-water solution.
Fig. 169.
Performing Cupping and First Redrawing Operations
on a Niles-Bement-Pond Bulldozer
Fig. 170.
Annealing Cartridge Cases in a Quigley Oil Furnace
for Thirty-five Minutes
First, Second, and Third Redrawing and Indenting Opera-
tions. After annealing and washing, the cases are taken
back to the Niles-Bement-Pond bulldozer, shown in Fig.
CARTRIDGE CASES 217
169, and the first redrawing operation is performed as
previously described. They are again annealed, washed,
etc. Following this, the second redrawing operation is per-
formed on a Williams & White bulldozer, where the punch
and die are held in the same manner as for the first redraw-
ing operation. Annealing, washing, etc., follows the second
redraw. The head end of the cartridge case is now indented
in a Williams & White bulldozer, where the base end is
formed to the shape shown at D, Fig. 168, and is then given
the third redrawing operation without annealing as shown
in Fig. 172. Here the operator removes the case from a
Fig. 171. Immersing Cases in Cooling and Pickling Baths following
Annealing
tank which is filled with a lubricant "Viscosity" and
places it on the punch, as illustrated, when the cross-head
is on the backward stroke.
Following the third redrawing operation, the case is
again annealed, washed, etc., and is then taken to the
Williams & White bulldozer, where the fourth redrawing
operation is accomplished. After the fourth redrawing
operation, the case is annealed, and then taken to the second
indenting operation. This is accomplished in a Williams &
White bulldozer at the rate of 300 per hour.
At this point, an operation is performed that is not gen-
eral practice; a 14-inch hole is drilled through the primer
218
CARTRIDGE CASES
pocket. In attempting to form the head of the cartridge
case with the primer pocket solid, it was found that the
metal in the proximity of the pocket was much harder than
Fig. 172. Third Redrawing Operation on Williams & White
Bulldozer
Fig. 173. Performing Fifth Redrawing Operation on a Frog
and Switch Planer
at the rim. This is just the reverse of what is required;
in other words, the rim must be much harder than the
center of the head. But, a hole drilled through the pocket,
in the heading, allows the metal to flow freely to the center,
CARTRIDGE CASES
219
Fig. 174. Heading Cartridge Cases on a C. P. R. Heading
Machine
Fig. 175. Mouth-annealing Cartridge Case in an Improvised
Annealing Furnace
220
CARTRIDGE CASES
and thus prevents "packing" and subsequent hardening.
Following the drilling of the hole in the primer pocket, the
Machinery
Fig. 176. Diagram showing Dies and Heading Tools used in
Machine shown in Fig. 174
Machinery
Fig. 177. Dies used for First and Second Tapering Operations
on Cartridge Case
case is taken to a Toledo case trimmer, where the open end
is trimmed, removing the ragged edge from the mouth of the
case.
CARTRIDGE CASES 221
Fifth and Sixth Redrawing Operations. The fifth and
sixth redrawing operations are handled on a frog and switch
planer, as shown in Fig. 173. The entire cross-rail has
been removed and a large casting A, serving as a punch-
holder, is fastened to the uprights. The redrawing punch B
is therefore held stationary. The redrawing die, on the
other hand, is held in a holder retained on casting C bolted
to the planer table. The method of operating is to place the
Fig. 178. Hand-reaming Primer Pocket in Head of Cartridge
Case
case on the punch when the planer table is on the return
stroke. The punch and die is lubricated by a lubricant
held in box D, which, of course, travels with the die. The
case, in being forced through the die, slides down a trough
into a box.
After the fifth redraw, the case is annealed, washed, etc.,
222
CARTRIDGE CASES
and is then given a sixth redraw which is accomplished in a
similar manner to the fifth. The mouth of the shell is again
trimmed on the Toledo case trimmer and from here is taken,
without annealing, to the heading press.
Heading. The heading operation is now performed in
the 350-ton press shown in Fig. 174, which is built by the
Canadian Pacific Railway. This machine is provided with
a table of the indexing
type which carries
four sets of dies,
shown in detail in Fig.
176. In heading, the
case is given two
blows; the first is de-
livered by punch A,
which fills in the prim-
er pocket. Punch B,
which is held on a rod,
as shown in Fig. 174,
is then placed over
the case and a flatten-
ing blow is delivered.
While these opera-
tions are being per-
formed, the case is
supported by punch
C, Fig. 176.
Mouth-annealing and
Tapering. The next
operation is mouth-
annealing, which is accomplished in the simple furnace
shown in Fig. 175. It comprises a stand which supports
an air drill, a spindle A, fitted into the driving socket of
the drill, and a table attached to this as shown. The case
is supported on this table and rotated by the air drill ; the
annealing is done with an oil burner. The case is allowed
to rotate for thirty-five seconds and is heated to a
temperature of 800 degrees F. (427 degrees C.) for a dis-
Fig. 179. Testing Hardness of Cartridge
Cases with Scleroscope
CARTRIDGE CASES
223
tance of about from 41/2 to 5 inches from the mouth of the
case.
After mouth-annealing, the cases are allowed to cool off
in the air, and when cool are taken to a Williams & White
bulldozer. Two tapering operations are necessary to bring
the case to the correct shape and size. The dies used for
this purpose are shown in Fig. 177. The first tapering die,
shown at A, is made in three pieces. For the first taper-
ing, the mouth of the shell is not supported, as the reduction
is carried along the entire body. In the second tapering,
however, the reduction at the mouth is greater and necessi-
tates using a supporting bushing a, as shown at B.
Machining Head and Mouth Ends of Case. Following
the tapering opera-
t i o n s , the cartridge
case is taken to the
machining department
where a series of op-
erations is performed,
on the head and mouth
ends, on a Bullard fac-
ing, chamfering, and
trimming machine.
The order of opera-
tions is : Rough-drill
and counterbore, face,
trim, and chamfer
head, finish-chamfer
and face, under-cut
primer seat, finish-
counterbore, tap with
mouth.
The case is now taken to a special reaming fixture, shown
in Fig. 178, where the primer pocket is finish-reamed.
Hand tapping of the primer pocket follows this and is ac-
complished in a similar fixture. The case then passes
through a series of inspection operations, consisting in gag-
ing the diameter and thickness of the head, depth, diame-
Machinery
Fig. 180. Diagram showing Representative
Scleroscope Reading taken on Head of
a Cartridge Case
collapsing tap, trim and chamfer
224 CARTRIDGE CASES
ter, etc., of the primer pocket; over-all length, diameter
of mouth, etc. Another inspection is looking through the
case, from the head end, to detect whether any free spelter
is present or not. The cartridge case is then stamped on
the head end in a Noble & Westbrook stamping machine.
This finishes the machining and inspection operations on
the case.
Testing for Hardness. The hardness of the metal is
tested before and after each annealing and redrawing oper-
ation, and, for this purpose, the scleroscope is used. Fig.
179 shows an inspector taking a series of readings on the
head of the cartridge case. About one per cent of the daily
production is inspected in this manner, and Fig. 180 shows a
representative reading. The body of the case is also tested
for hardness at the points indicated in the illustration ac-
companying Table VIII. This table also includes the sclero-
scope readings obtained before and after every annealing
and redrawing operation. For taking a reading on the
body of the case, it is placed on the horn A, Fig. 179. Final
inspection, packing, etc., finishes the operations on the case.
CHAPTER XII
COST OF MUNITIONS OF WAR
At this time when the principal nations of Europe
are at war and the question of increasing the defenses of
the United States is being agitated, a few figures on the
cost of guns, etc., will be of interest. The following data
on the cost of guns, howitzers, mortars, mountings, car-
riages, projectiles, powder charges and fuses were fur-
nished by the ordnance departments, Washington, D. C., and
are therefore authoritative:
3-inch field gun $ 1,825.00
4.7-inch field gun 4,650.00
4.7-inch howitzer 2,150.00
6-inch howitzer 3,325.00
6-inch seacoast gun 6,700.00
12-inch seacoast mortar 11,000.00
14-inch seacoast gun 55,000.00
The costs of carriages and mountings for seacoast guns
are:
15-pounder barbette $ 5,000.00
5-inch barbette 13,500.00
6-inch barbette 14,000.00
6-inch disappearing 24,000.00
10-inch disappearing 37,000.00
12-inch disappearing 65,000.00
14-inch disappearing 85,000.00
16-inch disappearing 130,000.00
12-inch mortar 18,000.00
The cost of artillery carriages of the mobile or trans-
portable type is as follows:
3-inch field gun carriage $ 2,181.00
3.8-inch howitzer carriage 8,500.00
225
226 COST OF MUNITIONS
3.8-inch gun carriage $ 5,462.00
4.7-inch howitzer carriage 10,562.00
4.7-inch gun carriage 4,361.00
6-inch howitzer carriage 14,147.00
If manufactured in the government plant, a round of
ammunition costs approximately as given in the following,
but when purchased from manufacturers, the cost is higher.
3-inch field gun $ 10.00
4.7-inch gun 28.00
6-inch howitzer 43.00
3-inch, 15-pounder 15.00
6-inch 60.00
12-inch gun 500.00
12-inch mortar 300.00
14-inch gun 800.00
16-inch gun 1,200.00
The smokeless powder for seacoast ammunition costs 53
cents a pound when purchased and somewhat less when
manufactured by the government.
Following are data on the cost of naval guns, carriages,
etc.:
3-inch naval gun $ 3,973.00
5-inch naval gun 7,600.00
7-inch naval gun 21,850.00
12-inch naval gun 72,820.00
14-inch naval gun 112,000.00
3-inch gun mounting 2,500.00
5-inch gun mounting 9,860.00
7-inch gun mounting 11,000.00
12-inch gun mounting 52,357.00
14-inch gun mounting 44,000.00
3-inch projectile 1.97
5-inch projectile 8.72
7-inch projectile 62.00
12-inch projectile 165.00
14-inch projectile 400.00
3-inch gun powder charge 2.12
5-inch gun powder charge 9.40
COST OF MUNITIONS 227
7-inch gun powder charge $ 30.60
12-inch gun powder charge 147.40
14-inch gun powder charge 201.40
3-inch gun fuse 0.80
5-inch gun fuse 1.45
7-inch gun fuse 4.80
12-inch gun fuse 4.80
14-inch gun fuse 4.80
The cost of a torpedo is $8500 and of the explosive $350.
A navy rifle complete costs $20; pistol, $18. The navy
pays 53 cents a pound for smokeless powder and 14 cents a
pound for black powder.
The following data of costs of armor plates and shells
have been compiled from bids of private concerns :
4-inch naval gun shells $ 9.50
5-inch naval gun shells 12.00
14-inch naval gun shells 415.00
7374 tons armor plate, per ton 435.00
401 tons armor plate, per ton 486.00
290 tons armor plate, per ton 466.00
63 tons armor plate, per ton 376.00
INDEX
PAGE
Adapter, machining 177
Ammunition, fixed 23
Annealing cartridge cases 184, 212
Anvils for primers, making 208
Armor-piercing shells, forging 52
Armor-piercing projectiles 9
Assembling fuses .' 178
Assembling primers 210
Banding howitzer shells , 143
Benzol 39
Blanking cartridge cases 181
British 18-pounder shell . 5
machining 53
British detonating fuse, manufacture of 163
British high-explosive fuse 17
pellet charge 19
British howitzer shells 127
British shell blanks, forging 42
Bulldozers used for making cartridge cases. 212
Capped projectiles 11
Cartridge cases, manufacturing with bulldozers and planers. 212
manufacture 181
Center plug for fuses, machining 179
Chlorate of potash, American composition 28
British composition 30
Chlorates 40
Combination primers 30
Concussion fuse 15
Conveying apparatus for rapid handling of shells 161
Copper bands, pressing on and forming 78, 120, 135
Cordite 37
Cost of munitions of war 225
Cupping cartridge cases 181
Delay-action fuse shells 4
Detents, machining 176
229
230 INDEX
PAGE
Detonating fuse, manufacture of 163
Disks for primers, making 208
Dunnite 5, 40
Electric primers 28
Emmensite 38
Explosives, classification 32
Fixed ammunition 23
Forging high-explosive shells 42
French 75-millimeter shell 7
French 120-millimeter shell, inspection 123
machining 100
testing for strength 126
Friction primers 27
Fulminate of mercury 40
Fulminates 40
Fuses, assembling 178
delay-action 4
British high-explosive 17
British high-explosive, manufacture of 163
Russian high-explosive 20
general description 13
Gaging cartridge cases 198
Gas plugs 77
Gaine parts, machining 178
Grinding high-explosive shells 154
Guncotton, manufacture of 34
Guncotton press 35
Gunpowder 33
Hardness testing of cartridge cases 204, 224
Hardness testing of high-explosive shells 152
Heading cartridge cases 192
Heat-treating Russian shells 81
High-explosives 38
High-explosive shells, development 1
forging 42
types 2
Howitzers, loading 24
shells, machining 127
Indenting cartridge cases 186, 216
Inspecting British shells . . 75
INDEX 231
PAGE
Inspecting cartridge cases 198
Inspecting French shells 123
L oading primers 210
Lyddite 38
Machining British 18-pound shells 53
Machining cartridge cases 197, 223
Machining French shells 100
Machining howitzer shells 127
Machining Russian shells 80
Machining Serbian shells 88
Maximite 38
Melenite 38
Mortars, loading 24
Munitions of war, cost of 225
N itrobenzole 38
Nitronaphthaline 38
O give, machining , 92
P ellet, machining percussion 176
Percussion fuse, American 15
Percussion pellet, machining 176
Percussion primers 28
Picric acid 39
Planers used in making cartridge cases 212
Plugs for primers, making 209
Plugs, gas 77
Powder, black 33
smokeless 34
Primers, for cartridge cases 27
making 204
Projectiles, armor-piercing 9
capped 11
Pyrocellulose, manufacture of 34
Redrawing cartridge cases 186, 216
Russian 3-inch shell 7
Russian high-explosive fuse 20
Russian shell blanks, forging 46
Russian shells, machining 80
232 INDEX
PAGE
Serbian shells, machining 88
Shell fillers 38
Shell manufacture, tools and devices for 145
Shimose 38
Smokeless powder 34
Testing cartridge cases 198
for hardness 204, 224
Testing French shells 126
Testing hardness of shells 152
Tools and devices for shell manufacture 145
Trinitrotoluol 39
Varnishing shells 65, 159
Serbian shells 95
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