The Arizona sentinel., 1889-11-30
BORING A BIG GUN.

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Interesting Processes IN the Manufacture
OF Breech Loading annon.
At last the cannon is turned down.
and Is ready to be bored inside in
this operation it must be bored SO
straight and true that the boring tool,
entering at the exact center of the
small end of the cannon, will come out
precisely at the center of the large end,
seventeen feet away. Those of you
who have tried to bore a straight hole
lengthwise through even short bit of
wood will know that this work requires
not little skill and care.
When any of you boys have job of
boring TO do at your workbench, you
make fast the article to be bored and
turn the boring tool. 1t is just the 9TH
err way in boring a cannon. The bor-
ing tool, or bit is held firm and mo-
tionless, while the great mass of steel
to be bored turns around. This plan
is found 10 insure steadiness of the
"bt." 1t would be almost impossible
to make this bit firm and solid enough
to do Its difficult work. and yet free to
turn around in the c.nnon. So if you
had been at the side Of this gun-lathe
when the work was begun you would
have seen that the bit was motionless
except for slow advance into the
gun.
The bit attends strictly to business.
and steadily bores its way through the
steel. Most of you have been to the
country and have seen pig roofing"
in the ground. Imagine. then, the pig
to be standing still and the ground TO
be slowly passing under the pigs
snout and being rooted" and you will
have case much like that of the bit
and tho cannon. In fact, the boring
tool is called ''hog-nosed' bit. and it
roots up that cannon as if it enjoyed
the operation. No long. graceful curls
come from this boring. but small, crisp
shavings that are removed as fast as
they accumulate in order that the bOr-
ing tools work shall not be interfered
with. The bit is going into the steel at
the rate of three-eighths of an inch for
every turn of the cannon, and it is
making round hole almost large
enough for boy to put his head in
five and three-quarter inches in diameter.
AS the round hole grows deeper, the
heavy bar. on which the bit is fastened.
advances into the cannon steadily,
moved by number of wheels and screws
that form part of the lathe.
l must not lose sight of the shavings,
the little ones that come from the in
side, and the long, spirally twisted ones
that are turned from the outside of the
cannon. A military-looking man,
standing near the lathe, does not lose
sight of these shavings or trimmings,
either. This mans business is to care
fully inspect the borings and trim
mings. That is wha, he is paid TO do
Uncle Sam pays him, ana - expects
him t. earn his salary. The cannon is
being made for Uucle Sam and he IN
tends TO find out all its qualities.
whether good or bad. So the man eyes
the borings carefully. Now, if with
plane. or your knife-blade, you will cut
a thin shaving from bit of wood, it
will show any little flaw existing in the
wood from which it was sliced. The
tiniest knot-hOle or crack will show in
the shaving much more plainly than in
the wood itself So it is with lannon's
1t is a dreadful tell-tale, and
the fault-fnding man beside the gun
knows this perfectly well. He exam
ines the spiral turning. or the little
piece of boring, and finds no evidence
of a flaw or crack. The long spiral
strip is as smooth as glass and as
glossy as your sisters curls.
Into the solid steel the hog-nosed bit
roots its way until it is in so far thai
q little electric light must bear it COM
pany. 10 show the workmen how mat
ters arc progressing in the heart of the
cannon. After eighteen days of steady
boring, the bit lets daylight into the
bore of the cannon by emerging at the
other Tor larger) end. seventeen feet
away.-G. f. Miller, in St. Nicholas.