Savannah morning news. [volume] (Savannah) 1868-1887, 1885-08-31
BIG GUN MAKING.
Description of the Making of "a Modern
Steel Rifled Cannon.


Washington Aug. 25.-There is good
deal OF activity at the Washington Navy
Yard just now. The orders for resuming
work at the navy yards have set the man.
ayers of the yard actively at work, for
they believe that the Washington yard is
best fitted for the manufacture of big
guns for the navy. A lot of fine guns have
been made at the yard in the present
year, and it is all ready for business as
soon IA it is called upon. Preparations
are being made for the manufacture Of
l6-inch guns. Commodore Semmes, in
charge of the navy yard, says he thinks
the yard may be called on for manufac-
turing better guns and steel ships, and
that il will be able to do either or both.
The men employed in the yard are all
American machinists. Most OF them are
old employees of the yard. and some of the
best hands are men who have learned
their trade right in that shop and have
never worked elsewhere If required to
put 900 men at work in ten days 1t can
be done, and the whole Of them be found
without going out OF the district
Few people nave any very accurate idea
of what a modern steel rihed cannon
looks like, or how complex and difichlt a
process its fabrication Is. To the average
citizen the word big gun suggests a huge
mass Of cast iron with large hole in it
short, cumbrous, and ungaiuly. But the
modern steel gun is neither. On the con-
trary, 1t is the work of art, and, being so,
is thing of beauty. Ii be rims with what
is known as the tube which is the only
portion OF It that extends in an unbrOken
mass the entire length OF the gun. Ehis
tube is tine foundation Of the structure.
After being forged 10 the required
length and rough diameter, il Is bored
and turned with the nicely Of the most
delicate machine. II is then ready to re-
ceiye what Is called the Jacket" This
is another tube OF forged steel large
enough for the breecb, and Of the original
tube to be inserted in it for about one
third of the length OF the latter, measur-
ing from the breech forward. In pre-
pairing the jacket for the Insertion of the
tube, the two are so fitted that the bore OF
the former is few thOusandths of an
inch smaller than the exterior OF the lat
ter. The jacket is then heated to a black
heat, by which II is expanded sufficiently
to admit the tube, and Its shrinkage while
cooling forms "cOld we'll" and provides
what is termed in the technology OF gun
making the required "initial tensions
that Is TO say, the eXertion of q constant
pressure by the jacket upon the walls Of
the tube within. IL usually happens that
the compression produced by the shrink
Ing process is so enormous as 10 contract
the bore OF the original tube, under the
length of the jacket, sufficiently TO re-
| quire the boringhead TO be run through
again in order TO make 1t uniform.
After the jacket has been shrunk on the
surface It is again turned and polished
with mathematical precision. over this
again are shrunk number of rings or
hooks, also Of foreign steel, and the sur
face of this is again turned and polished,
when the weapon is ready for rihing.
This process does not require descrlp-
ton, as il is Identical with the familiar
method Of growing rfed small arms, ex-
cept, OF course that IL Is ON much
larger scale, the gun having been "built
up"-which, by the way, Is the technical
name fcr the above described process OF
Jacketing and hocping-now bears as
striking resemblance 10 large teit scope
with its joints EXTENDED, and is ready Ia
receive tue brecch mechanism: for q must
be borne in mini that all modern Steel
canlCns, properly s0-called are breech-
leaders. The first step in the develop
ment OF the breech mechanism is known
as "chambering." This consists in en-
larging the powder chamber OF the gun
10 diameter several per cent. IN excess Of
the diameter OF the rife bore, 10y which
device much greater charge OF powder
is enabled 10 be used than ever thought OF
In the ordnance Of the past epoch. Roughly
speak, X, the power OF modern gun is
calculated I'm proportion, as the diameter
OF its powder chamber exceeds that Of its
rired bore, relation being observed also 20
Increased length 10y means OF which COM
plete combustion of the entire charge Is
attained.
After the chamber had been bored out 10
the proper dimensions the breoch lock IL
lifted. This - n cylinder of steel upon the
periphery ot which are cut heavy screw
threads. These threads 40 into cores
ponding ones cut IN the hreech OF the
chamber or rather In the prolongation OF
the ball In the rear ~ the chamber, since
tubs cavity, which forms she seat OF the
breech-lock. is OF less diameter than the
chamber Itself, though somewhat lnrger
than the diameter of the rlled bali. II is
usually cut Just enough larger than the
riiied ball 20 admit The easy insertion of
the pr0iectiie which must make mechan-
zeal NJ.
Aiter the completion Oftho hrDoeh mech.
anlsm the gun 10 ready % he mounted ON
an experimental carriage for ilriug tests.
These tests are conducted hy Il liked
standard Of trial charges, which are con-
siderubiy heavier than those employed in
service. M al liz rufnnfn Iarf.II fIta nvars h.