Maryland independent. [volume] (Port Tobacco, Md.) 1874-current, 1917-08-10

How the Big Guns Are Made.
There are two classes Of guns-nava
guns and army or land guns. Becaus
they can be manipulated more easil,
than those Of a ship. land guns are tn
heavier. The largest naval gun is tn
fifteen inch gun, and the largest Ian,
guu Is the German howitxer or I6.I
inrh gun.
OF the two the naval gun fires a shell
weighing over half ton, while thu
other fires projectile a ton in weight
But the new giant sixteen inch gum
Of the United States defending til.
fsnama canal and New York at sand,
HFok shoot proIectiies weighing 2.37l
pounds, which IS over a ton. Thess
immense steel guns can sink. -..fp b.
roe 4 has .s;SicatIas II the ut On
t ssiii Having been determined By air
pAe or fower
IN these hup pieces arr made Is
desefNed as follows BY the Popular
Science Monthly The first step is the
making Of The pig iron from iron ore
III large furnsces Ike towers. called
blast furnaces. Then the pig iron Is
N lied with other ..eel in large steel
furnaces called "opeu hearth" until 1t
is freed Of its impurities and convert
ed into steel.
The melted steel, thin as water, Is
run from these furnaces into big iron
molds, where 1t is allowed to cool into
large solid cylindrical or corrugated
blocks. After cooling these are reheat-
ed and reduced in size by pounding
them with big steel hammers and
squeezing them in rolls until at last
the steel is pressed into a long barrel
like mass, the embryo of a real gun.
This long skeleton of the inside Of a
gun must be bored out from one end
to the other on immense lathes, some
over ninety feet long. Heavy as the
mass is, huge lathe turns 1t around
as easily IS body turns snool.
After the inside has been rifed or
scored to form an inside surface that
gives the shell a twist before II leaves
the mnzzle and causes 1T to fly straight
the lower or muzzle end Of the gun Is
made larger This may be accomplish
ed i'm one or two ways. Either add
tional shorter steel tubes are placed
over the main inner tube. or the main
tube is wound with wire and finished
with an outer tube. The wire wound
guns are usually the heavier and are
used on board ship.
The gun bound with wire is really
stronger than the one built of bands or
rings of steel, one on another, for the
wire re-enforces the gun tube so that
it will safely withstand the tremendous
strain which is constantly put on 1t
when 1t is fred, said TO be as much as
seventeen tons pressure on each square
inch.
In the case of built up" gun, as
II is called when made of hoops or
bands Of steel. the outer tubes or rings
are shrunk or sweated on-that is, they
are heated so that they expand or swell
a little, as all steel does when heated,
and then while hot they are fitted over
the inner part and allowed to cool and
shrink, or contract. In SO doing they
fit very tightly on the main tube.
In making a wire wound gun the
wire is wound or eoiled around and
around until more than 100, miles OF II
has been wrapped around the big can
non. A twelve inch gun requires III
miles of wire, weighing about thirteen
and one-half tons. Although the
strength OF the wire is such that 1t
gives great resisting force to pressures
exerted sideways. it does not bestow
strength lengthwise. Therefore an ex-
ira thickness of metal must be put on
the muzzle of the gun, where the vi
bration caused by the shell leaving the
gun is the greatest.
The breecl. or the back end of gun.
Is a very important part. Here the
shell is inserted in a specially built
chamber. After the shell is In place
the breech is Closed by the shutting Of
a very complicated and strong door.
II is fastened or fitted in the gun by
extremely strong screws, so that the
charge win not burst the gun open at
the back when it is fred.
Sometimes a shell explodes In the
barrel of the gun. In a wire bound
gun the wire tends to prevent a grave
disaster. II binders the steel tubes
from bursting into many pieces and
flying in every direction. The solid
gun is wholly built of tubes. while In
the wire wound gun there be one
or two tubes. over which the wire Is
wound with the jacket tubes shrunk
over the wire A bush for the breech
ring is screwed into the rear end,
which is also REINFORCED by a breech
ring outside.