The Salt Lake herald. [volume] (Salt Lake City [Utah]) 1870-1909, 1897-06-20

In the meantime the tube is placed
in a vertical position. muzzle down. in
the shrinking pit, where 1t is firmly
clamped Above the clamps stands IT
feet of it's length. bright and true. and
over which the jacket must be shrunk.
while hollow brass cylinder projects
from the floor below through the cen
ter of the tube. through which there is
a constant flow of water at an ordinary
temperature. This, that the tube may
be kept at the same temperature
throughout and unaffected by the heat
of the furnace only a few feet away
So important is this that the slightest
expansion of the tube. even the frac-
ton of a t1lousandth of an inch, might
be a serious matter. AS the jacket
approaches the proper degree of ex-
pansion it is watched constantly by
the master mechanic.
Temperatures and dimensions are
determined frequently and with great
accuracy. till, at the very moment the
proper stage is reached. the master
mechanic raises his hand, the giant
crane moves and is halted directly over
the furnace. The cover is quickly
hauled out of place. the tackle hooked
to a band around the jacket. the block
begins to ascend and the large cylin-
der is soon suspended in midair- The
master mechanic once more and for the
last time gauges its interior. II is
wiped off thoroughly, another signe<
and the crane moves a few feet south,
bringing it's burden directly over the
piece it will soon encircle. Here 1t is
accurately aligned and plum bed. one
finger is raised by that careful man in
charge. and, guided by the asbestos
padded hands of strong and perspiring
mechanics. the heavy load slowly de-
sends Not a word is spoken and the
10 foL hi
from the burning hot metal but by
the use of his fingers as signals regu-
lates the descent of the jacket.
RESULTS OF SMALL ERROR.
The accuracy with which it must be
guided, its great weight and the rapid
ity with which the operation must be
performed, combine to make the shrink
ing on of the Is jacket a most diff
ficult and delicate matter and the
strain on those in charge is intense dur
ing the Is or 20 minutes that the jacket
moves slowly into place. From the
moment 1t is lifted from its position in
the furnace it begins to lose heat. and
every minute counts. There is clear
ance of only Tooth of an inch between
the tube and the jacket, and the latter,
hot and heavy as it is, must not be al
lowed to come into contact with the
tube al any point, or. at any rate. any
contact must he extremely slight and
The slightest touch might
form a burr that would cause the jacket
TO stick. resulting in endless trouble
and expense, If not the loss of the value
of the Jacket in material and labor.
Happily, this accident has happened
only once. as far as | am able to ascer-
tain, and then it was not very serious
one. In all other cases this operation
has been a decided success. and usually
the Jacket is in place in l minutes after
il is taken from the furnace.
The parts remain in the pit for As
hours to cool after which the combined
tube and Jacket are placed in one OF the
arge Iathes. where II IS turned down to
receive the hoops. which are shrunk on
the Jacket and about two-thirdS the
length of the tube not covered by the
after. Each hoop is heated and ex-
banded and shrunk on while the unfin-
shed gun is in a horizontal position,
me of the large cranes doing the work,
after which this enormous weapon is
turned down to proper exterior dimen-
;ions and placed in the large rifiing ma
chine and the tube rified.
The delicacy of this operation can be |
appreciated when one realizes that the
piece to be operated on represents |
nearly 800. 600 worth of material and
proper depth and width and length, and
/ cut too deep or a cut too long, or any |
Ither mistake may ruin the gun But I
he machine is too perfect in its con-
itruction, too skilfully and thoroughly |
adjusted and too carefully watched and /
handled by the man operating it for any |
such accidents to occur, and, after 10 |
laws or two weeks on the machine the |
filing of the big gun is finished. From /
he rifiing machine 1t is lifted on TO /
arge fat car IN the center Of the build (
ne and run out into the yard. where II (
s deposited on blocks built up several /
Get high. a house built around it and |
he breech mechanism fitted, and the |
run is complete. From the factory 1t is
.hipped down the Potomac river TO the /
indian Head proving grounds. where it |
lndergoes many severe tests before
,eing installed on board of one of our
arge ironclads.
This marvellous product of machine
work. has been more than six months
n course of construction and is worth,
ompiete. 100000 1t is 479.1 inches long |