The Providence news. (Providence [R.I.]) 1891-1906, 1898-05-18
PrOjectiles
For
Warships

The complete story Of the manufac-
turc of one Of the big battlesh:p projec-
tiles has always been hard to obtain.
The Firth-Sterling Projectile works at
Demmlcr, near Pittsburg are barred to
an outsider, only representatives of the
government and officials Of the compa-
ny having access to all the departments.
Even the worlKmsn Of ono department
arc forbidden to enter another. Here is
the history Of the making of 10 inch
shell:
I'm the casting shop molten steel is
cast in solid piece about l216 inches
In diameter. From the casting shop il
goes to the forgeroom, where, after be-
ing reheated, it is hammered down To
104 inches being considerably elon-
gated in the process. 1t is then convey
ed TO the machine shop and placed in
specially constructed, lathe. Tho base of
the projecfiie Is. inserted in the lathe
"ohuck, "and the 'conical end is swung
from the lathe center. A ''roughing"
cut Is then run over the she'll, the shell
itself is pointed, aud then receives a
finishing cut. 81
The only parts of the she'll that bear
against the rified surface of the gun il
the larger part Of the conical end and
the surface of copper ring that encir-
cles the projectile near its base. The
copper is quite soft, SO does not injure
the rifing. After the finishing cut is
given to the projectile the diameter Of
the largest part of the cone is 10 5-1O0
inches, and that of the cylinder, which
is the body Of the projeotile extending
back from the cone, is o 90-100 inches
The workmen now apply the "band
score, =" which is a groove cut for the
reception of the soft copper band. For
a 10 inch projectile the groove is IA
inches wide at the bottom and quar-
ter inch deep. The groove is wider at
the bottom than at the top, so that the
copper band retains its position after il
has been placed in the groove and
pounded down until the copper swells
ont and fills the groove, thus taking
fiange hold on the underside.
Then the extracting score" is cut.
This presents sectionally a view like the
letter ", with the letter lying on one
side and the converging lines pointing
to the base of the shell. This groove is
made to permit tool to be fastened to
the shell when it is desired to withdraw
1t from the gun. The shell is put in the
cutting off machine, where the surplus
length is taken off. The next move il
the boring of five inch hole in the
base to depth OF IA inches.
In the process of hardening the shell
is suspended, point downward, in q re-
ceptacle filled with molten lead, and is
allowed to settle until the hot metal
rises above the cone base. At first the
temperature of the lead is 300 degrees,
but Is increased gradually to 1900 de-
grees. The work of heating requires
four hours, when the shell is withdrawn
from the bath and sprayed with water
to give IL hard exterior. 1t is then
plunged into bath composed Of secret
ingredients, and when withdrawn it is
cooled with jet Of water.
The projectile goes again to the ma
chine shop, the hole in the base is wild
ened half an inch and the depth is in
creased two inches The hole is "thread-
ed" q few inches and a screw plug is
inserted. The grinding room is the next
destination, and here the extreme di-
ameter Of the cone Is ground down to
ten inches exactly After a soft steel
cap has been fitted to the tip of the pro-
jectile, on the theory that when the
she'll strikes the armored side of bat
tleship the soft steel preserves the point
Of the projectile without interfering
with its penetrating power, tho shell is
finished as far as the Firth-Sterling
company Is concerned. 1t is exactly
27 Ia inches long. After it has been re-
ceived at some United States arsenal il
is filled with IN explosive compound and
is roady for its work of destruction.
All large projectiles, from the six
inch size up, are made as described.
The machinery at the Demmler plant
consists Of 12 lathes. boring mills, Q
cutting of machines, 2 tool lathes, Q
chasing machines, l grinding and 1 cen
teriug machine. This equipment is be-
ing re-enforced, as THO company has
enough work on hand for tho govern
ment and foreign countries to keep tho
plant busy for two years. New York
Sun.