The Bennington evening banner. (Bennington, Vt.) 19??-1961, 1915-12-31
TESTING A SHELL.
0r6eaIs Through Which a Big Gun
Missile Must Pass.
THE SOFT NOSE PROJECTILE.
Its Ability to Bore Its Way Though
Heavy Armor Plate Without Explod-
ing Until After Its Impact Was Dis
covered by Accident.

ing OhriI AFTER Its Impact was DIS
covered by Accident.
Everybody knows that the modern
shell is one of the most diabolical Of
mans inventions, but how many of us
realize that 1t is also one Of the most
delicate and complicated?
Recently some firms holding con-
tracts for making high explosive shells
took upon themselves TO correct a
detail in the specification, and, as re-
suit, certain thread was improved"
They will never do anything OF the
Kind again. because all their work was
rejected. The apparent absurdity--ii
is In fact an absolute absurdity, from
an engineering point OF view-is de-
signed OF set purpose.
There is 4 somewhat similar anon
ally in the big shell for peiptrating
nrmor plating. which was introduced
in consequence OF an accident. One
day test shell was fired at piece OF
drmor plating from the soft side, and
the proiectile went clean through It
and exploded after impact, whereas a
similar Shell fred against the trout
the hardened and tempered side-shat.
tered and left an indentation of only
few inches.
This singular incident set somebody
thinking. and in consequence the high
explosive armor piercing shell is now
given a soft nose. To the hard point is
attached cap of soft metal. with
which addition 1t will go through the
toughest piece of armor plate. What
happens on impact seems TO be this:
The cap spreads, holding the point and
so enabling it-remember that the shell
Is revolving rapidly-to force its way
unbroken through the hard face Of the
plate by sort Of boring action.
No less curious Is another fact con
corning the points OF such projectiles.
After the heads have been worked the
shells are left for weeks before they
undergo the next stage, because. strong
rs they look, they are liable to snap.
Why? Think Of the razor. Constant
stropping twists the grain, with the re-
suit that the steel gets tired" and win
not yield keen edge. But if you put
the thing away for q few weeks the
grain will return to its normal state,
and you can get satisfactory shave
In similar way the grain OF the steel
is affected by working. though of course
to a much greater extent, and until IL Is
set the makers must 80 cautiously.
Steel shows like eccentricity in the
making Of test gauges. Some Of the
measurements Of shells are very fine,
and the instruments employed are so
delicate that they have 10 ba used
quickly lest the heat Of the hand causes
the metal to expand.
Now. when a groove is cut in n piece
OF steel which is to be used as a test
gauge the work is laid aside for weeks,
perhaps months. Why not finish it at
once? Because the groove. though dead
true when cut out. may be otherwise in
short time. even though it has been
absolutely untouched.
As concrete proof of the elaborate
nature OF proJectile making take the
case OF the sLrapnel shell. The steel
portion undergoes about score of OPP.
erations. and the brass cartridge case
attached to the base requires about six
teen. counting from the disk Of sheet
brass to the finished article. Then
there is the fuse. the delicacy OF which
resembles matchmaking
Altogether the shell is subjected to
about forty inspections and may be re-
jected at any stage.
After shell has survived this ordeal
It ought to be, one would think, per.
feet, but test shell is taken from
every 120 and actually fred from a gun
into q bank OF sand. 1t is then again
examined. and IL the contour about the
powder pocket is expanded away goes
the whole batch, because If they were
fred the growing might be torn ont OF
the gun.
Perhaps the most striking illustration
of the minute care exercised in projec-
tile making is that every shell is weigh.
ed over and over again. If you produce
an eighteen FOUNDER high explosive
shell ii must be only few drains over
or under its normal weight; otherwise
il is rejected.
In this connection It may be Of inter.
est to note that an explosive shell that
weighs only about seventy pounds will
break into IL shower OF some 1,2OO
pieces. A single one Of the monster
uroiectiles fred from a fifteen inch ma
val gun VIA weigh 1.9J0 pounds. 1t
takes twelve seconds for the projectiie
~ A,x-e Ia r.
point of impact when firing at u range
OF five miles. TO fire battleship
broadside costs about $4,000. - Tx