The Butler County press. [volume] (Hamilton, Ohio) 1900-1946, 1914-07-31
MAKING A BIG GUN
One of the Amazing Conquests OF
Modern Engineering.
WEAPONS WITH SHORT LIVES.

engineer has certainly achieved some
| of his most daring conquests. for it is
| doubtful If there is anything more
wonderfully fashioned or scientifically
! constructed than the monster weapons
found on the latest battleships and in
large forts
| From their muZZles they are capable
OF launching into space shells weigh
ing as much as half ton at speed
of thirty-fve miles minute, or 2, 100
miles an hour. These death dealing
missiles may be so designed as to
burst after they have forced their way
through a ships side or Immediately
| they strike an object or at some point
| during their fight
The big gun itself consists of sew
one another and named after the let
ters of the alphabet "A" is inside
and scorched by the powder gases
"B" goes over "A and 50 on, the out
side tube of al being known as the
jacket
Each separate tube, or cylinder, is
| fashioned In much the same way In
the case of the IA tube for twelve
! inch gun huge solid steel ingot is
cast. weighing upward OF thirty tons
The ends having been cut off, the in
| got is mounted in a lathe, and tube
like trepanning'' borer removes a long
core from the center The iugot is
1 tbap dicnouptpd from tho Lathe anI
heated long hollow bar somewhat
smaller than the destined bore of the
gun is passed through the central hole
and the ingot is placed under a $500
ton forging press. which gradually
thins and draws it out along the bar
which is kept cool by water circulat-
ing through it. After being turned
outside and bored inside the tube has
to be tempered, and this is done by
dipping 1t into a tank filed with thou
sands Of gallons of cottonseed oil.
AS it would be impossible to slp the
"B" and "C' tubes over the "A" tube
when cold, this difficulty is got over by
heating them. The work, however, re-
guires great care and constant atten-
ton. The heated cylinder. of course,
decreases in length as We'll as in diam
eter as it coolS, and. unless great pre-
cautions are taken. it would naturally
cool at the ends first, and cause the
central part of the tube to cool III q
state Of dangerous tension. TO avoid
such a thing happening one part is
cooled artifcially by means of water
] TT
ed by gas flames
We now come to the wiring process.
! Layers of rihbon-like steel wire are
wound outside the iunermost cylinder
but one. as metal arranged in this
manner Withstands bursting strains
better than anything yet devised, A
twelve inch gun consumes no fewer
than 100 miles of wire one-quarter
inch wide and one-siXteenth Of an inch
thick.
That the shell may travel "business
end" foremost throughout its journey 1t
must be given twisting motion round
it's axis-in other words, be made to
spin. This rotation prevents its turn
ing head over heels, as it undoubt
edly would do if not spinning. and
makes il travel farther and more ac-
curately. The spinning motion is
brought about by rifing-the cutting
of spiral grooves in the bore, or in
side of the gun This is done by a
long, hollow steel rod, which carries
three tools at the end and cuts three
grooves at once.
AS the riling comes so near the
end of the manufacture of a big gun
It must be conducted with the great
est care, for single badly cut groove
would spoil the gun, now representing
perhaps $4,000 in work and material.
Indeed extreme care and accuracy
characterize every process in the max
ing of heavy ordnance. The steel for
the tubes is made carefully; the ingots
are cast carefully and forged careful
ly. Every tube is bored and turned
10 the FIVE hundredth part of an inch.
Though n twelve inch gun is nearly
twenty inches thick over the powder
| chamber, each of its various jackets
must have its proper tension in order
to receive its fair share of the shock
of explosion.
Finally there is the breechblock-
the door through which the shell is In
serted. 1t moves on hinge and is a
very massive affair, weighing about
half a ton Thanks to the presence Of
certain levers and the perfection of
the workmanship, any one who has
the knack can move 1t quite easily. 1t
can be slammed and locked in about
five seconds. The door gives entrance
to the twelve foot chamber where the
shell Is placed.
The active life Of gun is made up
of the total of the very short periods
occupied by the various shells passing
through its bore. The bore of
twelve inch gun is about forty-fve feet
long and the average rate at which
the shell travels through it is halfway
between no motion at all and the muz-
zle velocity Of. say. 1900 feet per sec
ond. or about 1900 feet per second.
The riding of a big gun is worn out
| after 100 rounds have been fred so
that the tota life is the time taken
fer a shell moving at 1900 feet per
second to travel 4,500 feet THAT Is.
just three seconds