The Portland daily press. [volume] (Portland, Me.) 1862-1921, 1886-08-21
STEEL GUNS.
Difficult and Costly Process at the
Washington Navy Yard.
Washington Star.

The fabrication OF heavy steel rlne guns Is
a very delicate operation. A gun weighing
thousands of pounds must be constructed
with all the care and exactness OF chronom-
eter or any delicate mathematical lnstru-
ment. Some of the work is done under the
magnifying glass as carefully as ]eWeiier
would work up watch. The guns are mar
wells of workmanship. The first thing that
strikes one on entering the buildings Win
their dirt floors and great internal space up
to the high gabled roof is the massive and
ponderous character of the work. Every
thing about seems heavy. The cannon lie On
lathes like base ball bats being turned OUT
only the lathes are ponderous and the Dat-
are immense steel tubes, weighing thousands
of pounds, besides which man seems too
small to cope with it. This is where the
guns are assembled, that is, put together
made. The steel is brought here in the
rough, is tried by tests most delicate ana
tests most severe, is bored and smoothed ana
put together and worked into the finest and
most effective steel breeeh- loading rifle guns.
There is now lying in the shop one OF the
eight-inch guns, all finished and perfect,
ready to ship to Annapolis to be fired, and
the work on the ten-inch guns is well ad-
vanced. The finished guns are smooth anu
bright like immense steel needles. Iney are
ready to weave a thread OF flre through
plates of solid steel. One of the great needs
of the department is means OF moving tne
heavy guns from one shop to another AT
present this is done by means OF cranes ana
handcars but this is attended with many
dificulties. When the ten-inch gun, weigh
ing 81, 600 pounds, is placed on two OF the lit
tie cars and distributed over only twenty
seven feet of track, the track sometimes
sinks under the pressure.
The steel of which these are fabricated-Or
assembled" as they call lt-ls prougnt mere
in the rough, and is worked up to the high
est perfection of modern ordnance. Inc
work is all done with great exacnesS Dy
plans and drawings. The steel tube, which
Is the groundwork of the gun, is received
from the Midvale Steel Works, and Is here
bored and turned out, and then sent back to
Midvale for oil tempering. When 1t is re-
turned to the Washington yard 1t Is Dored
again, and then it is placed on lathe, the
centre being found on each ehd, ana Is turned
to a finished exterior diameter: The lack
et' is received in rough-that Is, In GYM
drical mass-from the same works. 1t IS
rough-bored here. Sometimes it Is sent back
to Midvale for an oil bath; sometimes not
The work OF putting the Jacket on !nIs
and one very interesting to watch. Inc
Jacket is put in a fire made OF pine
wood, and is heated sufficiently to remove q
portion of the shrinkage, and then III Is Dored
to the length and diameter of the drawing.
It is then 7'star gagged" and is ready to. be
placed on the tube. The tube Is placed on
end, like a needle on its point. The lack
et' is then heated sufficiently to exPand II
about O3 larger than the tube on its interior
diameter. The greatest care has TO pc TAKEN
to get Just the right temperature. When SUI
ficientiy heated the Jacket is slipped upon
the tube and clamped. 1t is first cooled at
the point nearest the muzzle by means OF
E BOO.
the tube, welding itself there. The hoops o. 81
variously tempered steel marked -. u; ~.
g." are slipped upon the tube. Alter tnaI
the "a. B. c." hoops are put on
During this process there Is various turn
ing and working down. The chamber is
bored, the trunnion bank put on and the
screw box fixed. After this the gun has to
be bored again. Next comes the rltlng,
which requires skill and care. In the hrst
shop the reporter entered several men were
working upon one end of an immense steel
tube, which was hot, and upon whlch they
were pouring small streams OF water. III
was the big ten-inch gun, upon when the
men were just putting his Jacket.
turning slowly on lathe, while man with
a sharp instrument pared off long, slender
curls of cold steel. An officer stood Dy Win
large magnifying glass, examining tne
smooth surface with great care as u reVotved Ed
before him. No matchmaker ever watched
his work more closely. The works OF a
watch do not require mere care and exact
ness The reporter looked through the
tube Through its entire twenty-seyen rect
of bore the light shene as on mirror; the
the twisting grooves were a marvel OF exact
ness. ., Al.
gun is levelled on blocks and secured:
Squares are adjusted at the breech ana
muzzle, and thread is so drawn as to rep
resent a line parallel to the axis on the top
surface, and along its course from breech to
muzzle face, tangent with the surface at
trunniOn band and so marked for the centre
trunnion sight; also at the point Tor the
breech sight From the axle lines are lald
off by squares on the left trunniOn, the point
for trunnion sight, which is screwed into the
trunnion. The trunnion is the band near
the balance centre, by which the. gun Is
swung to the carriage. This Is only bare
outline of the work done; the details are MI
mute and technical. The weight OF the guns
| is something enormous; the fiyes weigh CIV
pounds, the skies II ,O00 the eights 28,OOO, the
tens $1,000, and the ten-and-a-halt oO,0OO.
The ten-inch gun throws 5O0-pound prolec-
tile and burns $50 pounds of powder at a
charge. The tensile strength of the metal OF
which the guns are made is 10000 POUNDS 10
the square inch. The penetratiye power at
500 yards is one and third times the diame-
ter of the projectile. The number OF hoops
on the gun increases with its size. The eStl-
mated cost of making the guns is, running
from the ives to the tens. $500, S9oOO, Slo'-
600 and $4,000.