The Fremont weekly journal. [volume] (Fremont, Sandusky County, Ohio) 1867-1877, 1872-10-25
How a Rlaed cannon is Made

How a Rihed Cannon is Made:
The British War Department has
issued ga Text Book of the Con
struction and Manufacture of the Ri
fed Ordinance in the British service"
Amid the technical details and prac-
tical calculations, we find some facts
of general interest pertaining to ar
tilery manufacture. The following
is the process of making a rifed
cannon now in use in theBriUishO Ord
nance Service, on the Fraser princi-
pie:
A seven-inch gun of seven tons
consists of four pieces, viz, Il an in
ner barrel or tube of steel, or A tube;
over this (2) a B coiled tube, and
(3) a breech coil, with { ia solid for
ged cascable screwed in rear. The
steel is received from the contractor
in the form of solid ingot, which
passes through strict tests for tensile
strength and elasticity. It is first
rough turned and rough bored, ST
inches in diameter in 56 hours, and
the conical chamber formed in II
hours the roughly bored tubeis now
heated to an appropriate tempera-
ture, and plunged in a bath of oil, in
which it is allowed to cool for II
hours. The tnbe is again heated in
verticle furnace, and again sunk
into large iron tank 20 feet deep,
containing several hundred gallons
ofoil, around which supply or cold
water permeates for the purpose Of
cooling the oil. This cooling in oil
has the effect of toughening the steel,
but it also warps it slightly, and
sometimes causes the surface to
crack; the barrel therefore must
again be slightly turned and bored,
to make it straight inside and out.
The tube is now subjected to the
water test, to discover flaws which
may not be visible to the eye. By
a mechanical contrivance the interior
of the tube is subjected to a pressure
by water cf upwards of 81 tons per
square inch, and should there be no
formation of moisture on the exter
ior, the tube is considered sound.
Mean time the B tube has been
composed of two single and slightly
taper coils, welded under the steam
hammer, and rough and fine turned
and bored, ready to be SHRINK over
the A tube; and the breech coil is al
so prepared. The breech coil or
jacket is composed of triple coil,
trunion ring, and double coil, all
welded togther.
The trunion ring being dropped
on to the shoulder of the triple coil
and the double coil dropped through
the upper portion of the trunion ring
on the triple coil, the trunion piece,
being heated to redness, in cooling
grips tightly the two coils. The
Whote mass is then raised to Welding
heat in furnace, and then quickly
placed on its breech under the most
powerful hammer in the department
and welded; a cast iron mandril being
placed in the bore to obviate any bull
ging within. The breech-coil is now
turned in very powerful lathe and
slotted smooth in a self-acting verti-
cal machine; the trQnions have to be
shaped in break lathe, and the
| jacket is finally rough and fine bored,
and partially recessed over the B tube
and the female screw. cut for the cas-
cable. The gun is now to be built
up; B tube being snrunk over the A
tube, and the half-formed gun COM
posed of A and B tubes shrunk up
being next placed standing on its
muzzel in the shrinking pit, the jack
ct is heated for ten hours and shrunk
on. The gun begins now to present
a recognizable shape: the forged cas-
cable has to be screwed in, a small
gas-escape channel being cut along
it to warn the gun detachment if the
steel tube should split. The gun is
now fine bored and fnish-bored to
6" 997, occupying 26 hours, and
"broadhed" and "lapped" with pecu-
liar cutters to insure the trueness oi
cylindrical bore. Finally, the gun is
rifed, the finch with a uniform spi-
raj, and the higher natures with q
uniformly increasing spiral; the
number of the grooves varies with
the calibre; 7-inch guns have three,
8-inch four, 9-inch six, I0-inch seyeh,
and higher natures nine. A length
of about two calibres is left unrifed
at the base of the bore as a powder
chamber. When the gun is fitted
With steel vent it is ready for ex-
animation and proof. For this pur-
pose careful gutta percha impress
ions are taken of the whole length of
the bore, which is also accurately
guaged. At the proof-butt the gun
is now subjected to two rounds of
II, the highest service battering
charges and service projectile. After
proof the gun is tested by having
water pumped into the bore, the
pressure being 120 ID. in the square
inch, and again gutta perchaimpress-
ions are taken: should there be any
doubt as to whether any slight de-
tects have increased or flaws devel-
oped, the gun is subjected to five
more rounds, and if after that the
defect does not appear to have in
creased the gun is passed. After
proof, the gun is finished, sighted
&c, and issued for service.