The Rock Island Argus. (Rock Island, Ill.) 1877-1885, 1885-06-08
BIG BREECH-L
cANNoN-MAklNG AT THE SOUTH
BOSTON IRON WORKS.
Inc Process of Shrinking Forged Steel
Jacket on IOO-Pounder Rifle
Shrinking Rings" Upon the
Jacket Delicate Work

Boston transcript
A representative of The Trauscript mazda
visit to the South Boston iron works last
week, to witness the shrinking of n series OF
steel rings upon siN-inch breech-loaline
rifle cannon, of the same metal. now in mo-
cess OF manufacture. This gun is one of a lot
oil SIX OF like caliber and two Of eight-inch
bore, to form part of the armament of the
new cruisers ordered by congress. These
guns are all of the built-up pattern A brief
description OF the cannon upon which the
workmen were engaged at the time of the
reporters call will make the meaning OF this
term clear. This gun, when completed, will
weigh 1000 pounds and will carry a 100
pound projectlle, propelled by powder
charge of fifty pounds. The initial velocity
OF the shell is estimated at 1900 feet Der
second, and the effective range of the gun a !
seven miles.
The extreme length of the piece is 193. 50
inches The diameter of the chamber is
seven aud half inches, and its length. in
Guiding slope, thirty-seven and a half inches
The nhing consists Of twenty -four lands
and twenty four grooves IA land being tho
raised portion between the grooves or in
dentatiaasl, with increasing twist of one
III, y
lance of l34 inches to increase to one turn in
thirty calibers. The width of the grooves
| decrease five one-hundredths of an inch from
breeeh to muzzle end OF bore. The breech
mechanism is of the Interrupted pat
tern, and in rear of the nose plate is an as
bestos and mutton-suet ring, which serves as
gas check. The foundation of the gun is q
steel tube lS4 inches in length which is
cast in the rough at the Medvale steel works
in Pennsylvania, and which receives interior
and exterior finish at South Boston
| 1t is then ready for the Jacket" eylin-
der of forged steel, large enough for the
breech end of the original tube to be inserted
In it FOR about one-third the length of the
latter, measuring from the breech forward
! This tube is set up on end, and the Jacket
whose inside diameter is few thousandth
OF an inch smaller than the exterior of tbs
tube, is expanded by the heat and then low
cred into the tube after which it is shrunl
| by jets Of cold water, making what is called
n cold weld. The jacket extends back of tht
tube 9.53 inches, to accommodate the breecl
mechanism. In the same manner excepting
that the tUhs is disposed horizontally, fiv,
steel rings are shrunk upon this jacket, il
addition to one jacket hooking ring one tub
hooking ring, and three chase rings; anC
again, outside Of the jacket rings, are tn
trunnion ring (which is screwed ON and tn
elevating ring. The forward part of tn
tube seventy -cne inches from the muzzle
tie only portion Of the gun not re-enforced
The process Of shrinking on the JACKIE
and rings is very delicate one The ex
panding is done entirely by gas the JACKIE
or ring, US the case may be, being introduces
into anetwork of powerful gas jets, whic
surround the metal both externally and in
ternally with fame. Having been SUI
ficientIy expanded, which requires a TEN
. perature Of ahout go degrees, the jacket o
ring is slipped ever the tube, an hydrauli
jack of 100 tons power pressing the envelof
inS band home. So well does this jack rel
form its work that the joints between Il
several rings are almost imperceptible an
are often no wider tAan two one-thouSandtl
of an inch The next process is the shrinl
lag. which is done by cold water, as alread
mentioned. The shrinkage Of the jacks
amounts to one-hundredth of an inch, of Il
iac'et ring twenty-iour -hundrelths, ar
Of the chase rings from nineteen to sixte3
one-amd"edthS While the shrinking is g
T" ing on, the Temperature Of the tube is kel
down by a stream Of water running the q
tire longth in side.