Evening star. [volume] (Washington, D.C.) 1854-1972, 1897-06-19

geses to the rear. Each and every part Is
made Of the finest grade of steel, thorough
ly tested before using. and must be made
as accurate in every feature. all dimensions
true as the best electrical drills and 9TH
er tools can make them. No work is more
accurate than that of making and fitting q
breech mechanism. for on 1t principally the
safety of the gun depends. Sits and
grooves, cogs and worm-vsheels, racks.
pinions and levers, are scientific ally COM
bined and perfectly fitted. All breseh clos
screw system. and just here 1t is proper to
note that all mechanisms for operating the
breech plugs are the inventions Of Ame-i-
can naval officers.
Besides the shops mentioned, there is an
ere Getting shop and power house. from which
all power and electric lighting for the en-.
tire plant Is supplied, pattern hops, a
bronze foundry. chemical laboratories, test
Ing machines, smithery, drafting rooms and
offices, all complete and thoroughly equip
ped. The grounds cover an area Of more
than forty acres, of which more than TWEEN
ty is occupied by buildings, including Off
GERS quarters, and about twelve acres by
shops and offices.
Assembling the Parts.
All modern high-power guns are built UP,
that Is. they are made up of many pieces,
and the manner of assembling the parts
has many interesting features. In ma
Ginning the parts Of 13-ineh gun a de-
gree of accuracy Is required in shaping,
turning, boring and fitting that is found in
no other work done by machines on large
masses OF metal. From the moment each
piece is placed in the lathe, until the last
groove is cut, the work must be done with
the greatest care.
The gun proper consists Of long central
steel cylinder. called the tube, on the
bl eech end of which larger steel cyclinder,
called the jacket, Is shrunk, and a number
of other cylinders, called hoops, shrunk on
over all. In preparing the parts for as
IL r,<r t,,1N,.
accurate dimensions At the same time the
jacket is turned down to rough dimensions
and bored out to accur ite dimensions the
interior diameter of the latter being little
less than the true exterior diameter of the
former. When the interior of the jacket is
fiji ished the tube is turned down to it's
exact exterior diameter. The reason for
this is apparent. If the interior of the
jacket should, through any possible acct
| dent, be bored too large. the tube could be
turned to fit and the parts used without en-
dangering the strength of the gun; where
as. II the tube were turned down too much,
such would not be the case. To appreciate
the accuracy Of the machine work in gun
construction 1t Is only necessary to know
that all the dimensions Of the m ssive parts
must be true to the 1.00oth part of an inch
For the turning special calipers are made
ana r1gidly set at the different dimensions
by bringing its points into exact contact
WITH each one Of a set of steel rods one
| corresponding to each different dimension
| the length of each rod being determined by
measuring machine, which is kept in a
constant temperature. The interior Of each
piece Is accurately gagged by 4 most ac-
| curate gauge, which is also treated with
great care. When the tube and Jacket are
ready for assembling are prepared
| rather so far the machine work is con-
| cerned, they are lifted from the lathes and
deposited at the shrinking pit, where some
! OF the most interesting details of gun con-
| struction are carried out.
Fitting the jacket
| The jacket is placed in a vertical position
In the center of cylindrical friedrich fur
nace where it is expanded. The brick fur
mace Is inclosed in an iron cylinder, with
large air space between, and a heavy iron
cover fits over the top of both A constant
| supply of air is forced into the bottom of
| the outer cylinder, where it comes into con-
| tact with burning petroleum, and the heat
| cd gases resulting from combustion circu-
la,e around the jacket, and bring it gradu-
| any UP 10 the proper temperature, which
| does not exceed 800 degrees So gradual
| ana equal must the expansion be and so
| particular are those in charge to avoid any
| possibility of particles of grit or fora,gn
| matter adhering to the metal thai III a
! products of combustion are not brought in
70 contact with the Jacket at all. 1t re-
mains In the furnace about thirty hours be-
lore II reaches the proper degree of exnan
| SION during which time the cover is coca
s'onaily lifted off, the cylinder gagged along
us entire length and its temperature test
| ed at different points by the apnlicat;nn ~
strips of fusfble metal VI
IN the meantime the tube Is placed in a
| vertical position, muzzle down in fba
| shrinking pit, where it is firmly claimed
Above the clamps stands seventeen feet Of
| IT'S length bright and true, and over which
| the Jacket must be shrunk while a hoIlnu
Drass cylinder projects from the floor he.
low through the center of the tube thro,Srb
WHICH ihere is constant flow OF water al
| an ordinary temperature This. that the
| tupe may be kept at the same Temperatures
| throughout and unaffected by the heat Of
| the furnace. only a few feet away. So I'M
! OF the tube, even the fraction of 81 fhoY,-
sandtn OF an inch, might be a serious mat
| ter. AS the Jacket approaches the proner
degree OF expansion 1t Is watched constants
| iy by the master mechanic
temperatures and dimensions are deter
| mined frequently and with great accuracy
I'LL, at the very moment the proper STAGE