National Republican., 1883-05-10
MAKING STEEL CANNON.
bow Huge Blocks Of the Raw Material" Are
Turned and Bored into Great Guns.
The Two New "RiHes" Now Under Con
struction at the Navy Yard.

The two new 6-inch steel gun now being
constructed in the ordnance shops at the
navy yard will probably not be finished
for several months The work of building
them is necessarily slow one. All the labor
is performed In the shops here, except the
manufacture of the steel. That is done at
the Midvale works in Easton, Pa. The steel
then is shipped to Washington, and the work
of converting it to cannon is performed
This is a complex operation, and to the
locker on is decidedly interesting. The steel
is first turned" by a steam lathe working
slowly, but with tremendous power, until the
heavy mass of "steel in the rough" so to
sp eak, becomes long ylindrico-conoidal
column. In this condition it is placed in
proper position and O hole drilled clear
through IL by means of what is called
"hog bit" This hog bit is %
small rectangle of very hard steel, turned
up at one end in such D manner as to form
a rude vertical section of a spherical triangle.
The whole rectangular pieco is then clamped
down upon fiat shaft of chilled iron in
such manner as to at in and form ono piece
with the shaft. The latter has at the opposite
end cylindrical shape, which end is held in a
frame and worked by appropriate machinery
moved by steam upon one end OF the steel
column to be perforated. The end OF the
column is first dug into" little, and then
the hog bit does its work. 1t revolves on
its axis and the "bit" describes circle, tear
ing out the hard steel slowly but surely. As
the guns have bore of six inches diameter,
and the bit describes circle Of only ~
inches radius, the enlargement of the perfo-
ration is accomplished by other bits.
Once perforated, the now hollow tubes of
steel requires TO be "jacketed," "collared,"
iand "breeched" before 1t is allowed to gradu-
ate into the society of cannon. The Jacket
is an outside wrap of steel, followed in the
same way, heated until IL expands sufficient
to be slipped over the tube it is intended to
Jacket. Upon cooling this outside wrap
contracts and presses upon the now inside
tube with almost the same degree of cohesion
rs the molecules of the steel themselves.
The object Of the Jacket" is to strengthen
the gun and prevent accident.
The explosive force of the gases evolved
from gunpowder being tremendous, and oc-
curing mostly at the breech, the primary
object Is to strengthen this latter part. Col
lars of steel, great blocks Of the carbonized
iron, having been turned into shape and per-
torated, are next expanded by heat, and
slipped over the breech part of the gun.
When contracting they grow into
and become part of it, The breech head
of the gun is next lathed and
fashioned, different workmen being employed
on different parts of this. The riding of the
gun is another step. A different kind,o of "bit'
from the hog" spur Of steel tempered to
great hardness is clamped to the center of a
semicircular piece of copper and iron, and this
last device is slowly worked through the gun
on spiral turn, giving the rifle twist"
The breech head is then grooved and ad-
.justed, and the breech cap formally adjusted
This, as 10 known to all who have examined
breech leaders, swings back on hinge OF
spring, and when closed is securely locked by
q lever clamp.
The body of one Of the guns-tbat is, the
inside tube-is now ready. Work is being ac-
lively pursued on the other and on the various
mechanism that goes to make up one of the
new improved ri1ed cannon. Some of it, the
breech part especially, is complex, and re-
quires skillful workmen, special tools and a
long time to be wrought successfully.