Northern Wisconsin advertiser. [volume] (Wabeno, Wis.) 1898-1925, 1900-11-01

the center OF the tube, through which
there is constant flow Of water at
an ordinary temperature This, that
the tube may be kept at the same tenn
perature 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 fraction of a thousand.h of
an inch, might be a serious matter.
AS the jacket approaches the proper
degree of expansion it is watched con-
stantly 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 quick
ly hauled out of place, the tackle hook
ed to band around the jacket, the
block begins to ascend, and the large
cylinder is soon suspended in midair.
The master mechanic once more and
for the last time gauges it's interior,
it is wiped off thoroughly, another sig
nal, and the crane moved few feet
south, bringing it's burden directly
over the piece 1t will soon encircle.
Here it is accurately aligned and
plumbed, one finger is raised by that
careful man in charge and, guided by
the abestos-padded hands of strong
and perspiring mechanics, the heavy
load slowly descends. Not word is
spoken, and the master mechanic
never takes his eyes from the burn.
ing hot metal, but by the use of his
fingers as signals regulates the de-
scent of the jacket.
The accuracy with which it must be
gMided, it's great weight and the rapid
ity with which the operation must be
performed, combine to make the
shrinking on 13-inch jacket most
delicate matter, and the strain on
those in charge is intense during the
fifteen or twenty minutes that the
jacket moves slowly into place. From
the moment it is lifted from its POSI-
tion in the furnace it begins to lose
heat, and every minute counts. There
is a clearance of only 4-lOOth of an
inch between the tube and the Jacket,
and the latter hot, and heavy as it is,
must not be allowed to come into con-
tact with the tube at any point, or,
at any rate, any contact riust be ex-
tremely slight and momentary. The
slightest touch might form a burr thai
would cause the jacket 10 stick, re-
sulting in endless trouble ard expense,
IL not the loss of the value of the
Jacket in material and labor. Hap
PLY, this accident has happened only
once, as far as am able to ascertain.
and then it was not very serious one.
In all other cases this operation has
been decided success, and usually the
jacket is in place in fifteen miutes af-
ter it is taken from the furnace.
The parts remain in the pit for
forty-eight hours to cool, after which
the combined tube and jacket are plac-
ed In one of the large lathes, where
it is turned down to receive the hoops,
which are shrunk on the jacket and
about two-thirds of the length of the
tube not covered by the latter. Each
hoop is heated and expanded and
shrunk on while the unfinished gun is
in horizontal position, one of the
large cranes doing the work, after
which this enormous weapon is turned
down to proper exterior dimensions
and placed in the large rifling machine
and the tube rifled.
The delicacy of this operation can
be appreciated when one realizes that
the piece to be operated upon repre-
sents nearly 100000 worth of mater
ial and labor. The grooves must be
cut just the proper depth and width
and length, and a cut too deep and a
cut too long, or any other mistake,
may ruin the gun. But the machine
is too perfect in its construction, too
skillfully and thoroughly adjusted,
and too carefully watched and handled
by the man operating it for any such
accidents to occur, and after ten days
or two weeks on the machine, the
rifling of the big gun is finished