The sun. [volume] (New York [N.Y.]) 1833-1916, 1897-06-20

are OF the slotted screw system. and Just here It
atins the brecch plugs arc the inventions Of
American naval officers.
Besides the shops mentioned, there 10 an erect
Ing shop and power house. IRON which all power
and electric lighting for the entire plant IL sup.
pied; pattern shops, q bronze foundry, chemical
laboratories. testing machines, sTnithy, draft
ing rooms and offices, all complete and thor.
ougbly equipped. Tho grounds cover an area Of
twenty acres IL occupied by buildings, including
officers quarters and about twelve acres by
All modern high.powcr guns are built mp; that
manner Of assembling the paris has many inter:
esting. features. In machining the parts Of n
l3-inch gun a degree OF accuracy il required In
shaping. turning, boring, and htting found in no
metal. From the moment each piece Is placed
In the lathe until the last groove IL cut the work
must be done with the greatest care.
cylinder, called the tube. on the breech end OF
WHICH a larger steel cylinder, called the Jacket,
called hoops, shrunk on over all. In preparing
tho parts FOR assembling the lube Is turned
6own to nearly accurate difnensiops and bored
the Jacket 10 turned down to rough dimensions
and bored out TO accurate dimensions, the into
the truo exterior diameter Of the former. When
tho interior OF the Jacket ia finished the tube Is
reason for this Is apparent. IL the interior OF
should be bored too large, the tube could DO
'o' - q NJ oit - p"i 70 ipSN .bhSe'
gcr:ng the strength of the gun; whereas, II tho
tube were turned down too much, such would
the machine work in gun construction 1t is only
necessary to know that all the Dimensions 1.-THE
massive parts must be true to the ono thou
sandth part Of an inch.
For the turning special ~calipers are made and
riRidly set at tho different dimensions by bring
ing the points into exact contact with each one
OF q set OF steel rods, one corresponding TO. each
different dimension, the length OF each rod being
determined by n measuring machine. which 10
Kept in "A constant tenlDeraturC. Inc interior OF
each piece Is accurately gauged ny a most &C
e eare. Wien WEN the me't tube 5s and and jacket are S ready yff for
assembling. or are prepared, rather, 80 far as the
machine work L. concerned. they are lifted from
where some Of the most interesting details OF
gun construction are carried out.
tho centre Of a cylindrical frebrick furnace.
where 1t Is expanded. Tho brick furnace is in
closed In an iron cylinder. with a largo air space
between, and n heavy iron cover fits over the
into the bottom of tho outer cylinder, where II
tho heated gases resulting from combustion
circulate around the Jacket, and bring 1t
E TSidh dSSos up not to sses ss9 eJ R50 asFre tsmP Sc sraS.
ual and equal must the expansion be, and so
particular are those in charge to avoid any posi-
herring TO the metal that the products Of COM
bustion are not brought into contact with the
thirty hours before 1t reaches tho proper degree
OF expansion. during which time the cover is
S Sions rs ssni lifssd length of 's and eT III ssmps saSsss
tested at different points by the application Of
strips of fusible metal.
cal position, mpzzle down, in The shrinking pit,
where It is firmly elamped; Above the clamps
true, over which the jacket must be shrunk.
while a hollow brass cylinder projects from tho
hoor below, through, the centre OF the tube,
through which there is q constant flow of water
at, an ordinary temperature. This, that the
tube may be Kept at the Same temperature
furnace, only a few feet away. So important 10
this that the slightest expansion Of the tube.
might be a serious matter. AS the jacket APP
proaches the proper degree OF expansion 1t Is
watched constantly, by the master mechanic;
temperatures and dimensions are determined
frequently and with great accuracy till. at the
very moment the proper stage is reached. the
crane moves and is halted directly over the fur
mace. The cover Is quickly hauled out of place.
the block begin begins to S ascend around and The the 'a iarss
cylinder Is soon suspended in midair. The
master mechanic once, more and for the
crane Sn ' moTedf a Few f feet South s'ss rink:ins ant It's b sne
Here 1t is accurately aligned and plumbed. ono
finger Is raised by that careful man in charge,
strong and persiplrins mechanics, the heavy aSH'is load d
slowly descends. Not q word is spoken, and the
master mechanic never takes his eyes from the
burning hot metal. but by the use of his fingers
as signals regulates the descent OF tho Jacket.
The accuracy with which 1t must be guided, its
great weight and the ~rapidity with which the
operation must be performed. combine to make
the shrinking on ola l3-inch jacket a most deli
cate matter, and the strain on those in charge is
intense during the fifteen or twenty minutes that
the jacket moves slowly into place. From tho
moment it is lifted from It's position In the fur.
counts. There is q clearance OF only 4.lOOth OF
an inch between the tube and the jacket,
and the latter, hot and heavy as II ia, must
not to be allowed to come into contact with the
tube at any point, or, at any rate. any contact
slightest touch might form a burr that would
cause the jacket to stick. resulting in endless
trouble and expense, il not the loss Of the value
Of the jacket In material and labor. Happily,
this accident has happened only once. as far as I
am able to ascertain, and then 1t was not a very
serious one. In all other cases this operation
jacket Is in place in fifteen minutes after 1t is
taken from the furnace.
Tho parts remain In the pit for forty-eiRht
hours to cool, after which the combined tube
and Jacket are placed in one OF the large lathes.
hoops, which are shrunk on the Jacket and
about two-thirds of the length OF the tube not
expanded and shrunk on While the Unfinished
gun Is In a horizontal position. one. Of the large
cranes doing the work, after which this enor-
nous weapon is turned down to proper exterior
dimensions. and placed In the large rihing ma
chine and the tube rifed.
The delicacy OF this operation can DO appre-
ciated when one realizes that the piece to be OPP
Grated upon represents nearly 500. 900 worth
GU cut 9 iast the p sna ipS 9epth I nna E EfSaSe and n IeSst be
~lfN tAta biANl AtIR Hi
and a cut too deep or a cut too long. or any
other mistake. may ruin the gun. But the ma
chine Is too perfect in its construction. too skill
watched and handled by the man operating
It for any such accidents to occur. and after ten
days or two weeks on the machine The
riding of the big. gun is finished. From
the rifiing machine 1t is lifted on TO a large fiat
car in the centre of the building and run out
built up several feet high, a house built around
II and the breech mechanism fitted. and the gun
Is complete. From tho factory It is shipped
down the Potomac, River to the Indian Head
proving grounds, where 1t undergoes many Sc
we're tests before being installed on board OF one
of our large ironclads.
This marvellous product of machine work has
been more than six months in course OF con-
Btruction, and is worth, complete. 500. 600. II
is 479.l inches long, weighs sos tons. fires a
charge OF 900 pounds of slow-burning powder, a
steel proiectile weighing LOO pounds, thrown
with q velocity OF 2, 100 feet per second. and de-
yeloplng a muzzle energy OF 80. 1927 foot tons, or
"a, 000,O 900 foot pounds. and is capable OF pierre.
ing 2i.54 Inches of solid steel at a distance of
1000 yards from the muzzle.
The plant, while Just ten years old, has sufl-
cient capacity to more than supply the demands
Tor our growing naval armsments, Is worth, in.
GLIDING an estimated value of grounds and ali
buildings, nearly ", 0O0. 900, and has an annual
| Outnut Of ubOut 81 hnD 600 Az a $50 -.