The Union times. [volume] (Union, S.C.) 1894-1918, 1895-04-19
OUR NAVAL GUN FACTORY.
WHERE UNCLE SAM TURNS OUT
ENGINES DE DESTRUCTION

which is about go feet long,
4. with 4 width varying from
eighty to 130 feet, is wonderful
place. says the Chicago Record 1t is
n hlSh, bright room, and SO full Of
machinery that 1t seems impossible at
iirst sight for workmen to make their
way around. Overhead moves trav-
cling crane OF majestic proportions
that will easily lift and carry steel
guns weighing more than 100 tons. At
the north end the large cannon are
made, and the south end is devoted to
the 'barkers, or little guns. Between
the two is the ''shrinkinG-pit," from
which arises gust OF nir hot enough
to persuade the uniuitintcd visitor
that it opened directly into the infer
nal regions.
in the first place the gun Ia born in
tue head of the factory dranghtsman,
who sits in ~ clrau little Office where
the hum OF the shop is but barely au
diblc. Hc makes his drawings on paper
and figures out every dimension to the
thOusandth part OF m inch for the
least error may lIvO.ve the ruin Of
gun and the loss 81 thousands 0t dol
lars.
From the draughtsman tho specif.
cations go to the shop, where the
forgings of steel from tho Bethlehem
works are already in waiting Then
tho process Of building up" the gun
heSins. 1t has been discovered that
when Il gun is made up of central
tube" covered by 'jacket" and
rings" on the outside the metal is
more homogeneous aud will with
stand much greater explosive pres
sure.
The process of putting these pieces
together IL known as assembling"
and the work IS done N the shrink
ing pit. But before the gun is ready
for assembling it must have been
graduated from long course of lathes
aud boring machines. All one end OF
the big building is filled with them,
and the mechanism Is so perfect that
after they are started they will run
with almost no attention until their
work is completed. One of these
lathes is 13O feet long and has q swing
of eight feet. 1t is capable of boring
or smoothing a gun fifty feet long and
weighing more than 120 tons SO
Sohp ploUC io tuO Uuhb bLo
gun may be turned on tho outside
and bored on the inside at the same
time. Smaller lnthes Of every imagin-
able variety are used in making
smaller guns 0f various kinds.
On leaving the iathes the travelling
crane overhead carries the gun along
to tho riding machine. This plows
the interior surface of the gun with
spiral groove by which rotary mo-
tion is impaired to the she'll when it
is Tired 1t Is III operation requiring
the greatest care, for if the cutting
machine varies the thousandth part of
an inch or ii a particle Of metal crum.
hles off the efficiency of the gun is
seriously injured. Such delicacy Of
adjustment in such II ponderous ma.
shop.
The operation of assembling" the
gun is the climax OF the whole pro.
cess, and it is critical enough to make
the superintendent face worry serious
Cor several days The principle of the
whole process lies III keeping the
tube or main part Of tho cannon
cool and expanding the jacket by
means of heat so that it will slip easily
over the tube. Upon cooling the
Jacket contracts anu grasps the tube
almost as closely as if they were both
Que piece of metal.
Formerly the Jacket was heated in
the ''shrinkln2' by means Of burning
charcoal or wood. but this was found
to produce uueQunl expansion and
warpinS. At present the heating is
done entirely by hot air. In the pit
there is one furnace flied with coils Of
pipe through which air is forced by II
comprcssing pump. Underneath is a
gas fire which heats the air TO high
temperature. IN this condition it is
forced into the cylindrical apartment
i'll which stands the gun Jacket, md,
after passing through. it is carried OF
by chimney After having been
heated for lay or two the master
workman has the lid Of the Jacket
apartment lifted little and the top OF
the great cylinder Of iron is measured
TO see if the expansion has made it
large enough 20 lit over the tube.
When its inside diameter is one tenth
IT IN inch greater than the exterior
diameter of the tube the moment for