New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1891-06-19

The contracts for eun forgngs call for opcn-health
steel Of domestic manufacture the best quality Of
raw material uniform in quality and free from all
defects The metal is first run into solid nsots, which
are required 10 have excess OF weight Of 40 per
cent above that of the roughbored forging or this
exs,ss. thrcc-folrtls must be discarded from the
upper end Of the ingot and oneeehh from the lower
end. All fornngs must be annealed, oil-tcmpcred
and again annealed.
SIS much for the preparation. inspection and tests
of the raw material" Of modern gun for one Of the
new ships Of the American Navy. After that one is
not surprised TO learn that every gun built thus far
has stood the scvercst tests applied to II.
Now, as to the process by which the forgings that
have been prsnared as above described converted
into modern guns every part Of which Is as perfectly
finished and as accurately adjusted as the parts Of
n watch and which are not surpassed II they are
equajed in finish. accuracy strength or effectiveness
Nv like ems made IN the best gun factories Of Europe
The tubes ds received arc put In boring ana turning
lathe and bore smaller In diameter by about enc
quarter Of aa inch IS obtained. The jacket which Is
tho first piece be shruuk is In the mean time
bored TO It's exact diameter ana measured In every
inch by means Of the stareaufe. These dimensions
having been obtained, that part OF the tube which Is
IN 10 envcoped by the Jacket is turned down T. what
4 termed its shrinhage diameter that is the diameter
Of the bore ~ the jacket plus given quantity assigned
fr the shrinkage Of the parts ~ question: on SIX
inch Tube IL Is about 1900 Of all inch and the tube
T. therefore that much larger In Diameter than the bore
OF rs Jacket When beth tube ard jacket arc ready,
the former Is placed vertically In the shTnhlnsplt.
with Us hrcech or rear end mp, and the JACKET is placed
In the heating furnace whera it Is expanded sufficiently
to pass over The tube. with allowance for the necessary
time required TO perform the operation. The expanded
niece IS never raised above black heat nor Is the
expansion allowed TO exceed $1,000 Of an inch for
each inch OF diameter and IL is usually less.
The expansion is watched BY means OF trial gauges
and when sufficient the heated piece Is lifted by the
overhead crane from the furnace and SWING over Its
tubo and being carefully puibcd Is lowered slowly 70
It's seat Running water Is circulated through the
bore Of the tube and when the mass is cold tie gun
IS lifted from the pit and IT, bore Is stargauge1 to
ascertain what compression has taken place due to tle
squeeze OF the contracting Jacket. This compression is
In measure the test Of the accuracy OF the wEk NJ
10 this point The various hoops have IN the mean
time been bored aud measured. and the exterior II The
Jacket and uncovered end Of the tube arc prepared 10
receive them In tho same manner as the rear end u
the nbc was prepared for the Jacket ana each Is
nut on In rs proper Oricr until the gun Is fully as
scInbled The bore Is star gagged Bette and after
each layer Of overlapping parts u ascertain the tota
amount % compression.
When fully built-up the gun is bored 10 finished a.
mcns.uns the powder chamber Is bored ont and tho
screw cut for The bNcch Plug and the exterior !.
finished The piec- next sOcs to the r1mg-nachme