Evening star., 1912-11-24

some peHulAS over TO Hle away a tiny i'm
perfection, others glowing from the heat
of the giant furnaces in which the guns
are shrunk, one is filled only with the
realization that here IS being made, with
hand as well as brain, that part Of the
navy's equipment without which it would
be but a mOckery.
An average annual output at the gun
foundry Is about 200 guns, While all the
$500 men are not en-
Annual ployed with the actual
On+rr+ construction of the guns,
cartridge cases and gun
carriages also being made at the yard,
the majority are. Two hundred guns as
against about 1000 mep seems a small
proportion. And yet it takes a week. or
seven eight-hour Shifts merely to bore
one of the fourteen-inch guns; it takes
| three days to heat gun sufficiently to
! insert the inside liner and then 1t must
be inserted in two minutes without touch
ing, or the entire work has to be done
over again. 1t takes 100 hours or fifteen
working days, to rifle gun: and allowing
for taking it's regular order in the rou-
tine of work, it takes from three to six
months to make a single gun, according
to the size.
OF the twenty odd buildings which COM
prise that part of the navy yard actually
concerned with the manufacture of guns
and other ordnance, the most important
is the main gun shop. Almost a quarter
of a mile long, this building is the one in
which the actual work of making the
guns is done. Seven important operations
are connected with the manufacture Of
gun. besides innumerable minor ones.
Practically all of the rough forgings are
bought from outside establishments.
Consequently the first step in construc-
ton at the yard is the process known as
turning" The rough forgings are
taken and turned" to within 10000 of
an inch of the proper size and length for
the guns they will eventually be part
of. Next comes the boring, or the proc
ess by which the hole in each gun is
cut to the proper size. Third, is the
shrinking process. All the guns are made
up of several parts, each part being
shorter than its predecessor over which
1t fits. In order to put the guns together
the first section, which is the longest
is slipped through the next section while
| 1t is at almost cherry red heat, the
principle on which this is done being
merely that of heat expanding metals.
When the two pieces have been put
together they become practically one
after cooling. This method
Shrinking is used for the reason that
Mo4ol by making a gun of sew
eral parts, thus put to-
gether much stronger gun results than
if made of a single piece or cast. This
process of building UP a gun is known
as shrinking, and is continued until the
several necessary pieces have been put
| together. The gun is then again turn
ed'' and bored, in order to do away with
any imperfectionS which might have oc-
Cured during the shrinking. The next
process is termed rfiing. A projectile
shot from cannon in the same manner
in which it might be thrown by hand
would travel but a short distance. Its
carrying power consists in the rapidity
with which it Is revolving at the same
time it travels forward. "Rihing" con-
sists in SO growing the bore of the gun
that the shell is turned round and round
as it leaves the cannon.
During the time which has elapsed
before a gun has reached the rifiing stage
innumerable minor operations have been
gone through for the purpose of insuring
absolute accuracy in all its parts. When
fully completed, the gun lis sent to
Indian Head, the naval proving ground,
and there tested in@every way possible.
If found satisfactory, it is returned to the
navy yard and is there gauged and other
wise gone over to see that it has not
been injured in the process of proving.
1t is then ready to be shipped to what
ever point is to be its final destination.
/ The largest gun manufactured at the
navy yard is of fourteen-inch caliber. A
gun of this size is over fifty-three feet
| long, and weighs when completed more
than eighty tons unmounted and 40 tons
mounted. The proiectile used weighs about
| / 200 pounds, while the maximum charge
of smokeless powder weighs about 600
| pounds. The muZZle velocity of the pro-
/ jectile is about $500 feet a second, while
| the maximum pressure in the powder
chamber is eighteen to twenty-one tons
| per square inch. The maximum range Is
about thirteen miles, while the fighting
range is from 6,OOO to 10000 yards. at
which distance the projectile will pene-
| trate approximately eighteen inches OF
/ steel, depending, of course, upon its quail
! ity and the class of shell used.
| In making the guns the most important
point is accuracy. An imperfection hardly
perceptible to the eye might mean a seri-
/ Gus accident when the gun was fired at
| Indian Head or on shipboard For that
| reason all measurements must be exact
| to the smallest fraction of an inch.
| Guns are made Of what is called nickel
steel, which is purchased in open market
Owing to fluctuations in price,
| Nickel however, it is difficult to esti-
mate the cost of material for
otoei' a single gun. The number OF
| pieces which comprise a gun vary accord
I ing to the size, a twelve-inch gun, for ex-
| ample, being made of nine pieces, eX-
/ elusive of the breech mechanism.
| In manufacturing ordnance a large pro-
/ norton of the castings are made in the
/ foundry In one year these amounted to
3, 2S7 9S7 pounds. of which total the larg-
est single metal ingredient was bronze
| ], ,2S4, ,59S pounds being used. All told,
| fourteen different metals were used IN
the various classes of castings made In
1 addition to this "a total of 590,521 pounds
of bronze turnings and scrap bronze We're
used These had value of s cents a
pound. making the whole worth more
| than $4,000 this amount being s. we'd TO
| the government, as new mateflal old not