The watchman and southron. [volume] (Sumter, S.C.) 1881-1930, 1894-02-14
OLD AND NEW COMING.
A Modern Press That Is to Do the Work In
the Philadelphia HIint.

A Modern Press That Is to Do the Work In
the Philadelphia Mint.
The striking of medals in the coiners'
department of the United States mint
has for years been by means Of the
screw and fly press. The screw in this
press is inches in diameter, and there
are three threads with a pitch Of three
inches. The double lever attached to
the head of the screw is 13 inches in
length, or 61@ feet either way from the
center Of the screw, and upon the ends
of the arms are mounted balls weigh
ing about $50 pounds.
Three men are employed in the work
ing Of the press-one to arrange the
blanks to be struck upon OF between the
two hardened steel dies, while one at
each end of the lever furnishes the power
to raise the screw and then by rapid
movement cause the same to descend to
the work, they being careful at the
proper moment to step inside to avoid
being struck by the recoil of the lever.
Two and half revolutions of the screw
give with all the force the men can i'm
part blow or pressure equivalent to
$50 TONS.
In the striking of 4 inch diameter
medal some so or 60 blows are neces-
sary to complete the medal. The blank,
which becomes hardened by the force
of each blow, must be annealed. Each
time consequently the amount of labor
bestowed makes the cost Of such medals
quite high.
Some 19 years since the idea was con-
ceived that the introduction of hydraul-
ic pressure would be more satisfactory
and produce better results, both as to
cost and execution. The trial was then
made on an ordinary hydraulic press,
such as is used for forcing the wheels
of locomotive on the axle, made at the
machine works of William Sellers & Co.
An accident occurring in the burst
ing of the steel collar, by which the
then coiner Of the mint was injured,
had a dampening effect upon the
scheme, though the idea never met with
encouragement, until some two years
since, when an opportunity was offer
ed to make a test of the pressures re-
quired to make the various coins. This
being so satisfactory and having gain
ed the conclusive knowledge that for
years had been only guess work, it en-
couraged the revival Of the idea, and
plans and estimates were framed for a
press that should have a capacity of
striking pressure equivalent to 1000
tons.
The contract for this press was award
ed to Messrs. William Sellers & co. at
cost of $1,000. The designs having
been approved, the press was completed
in September, and upon trial at the
works the recu!t was most satisfactory.
The dies used upon the trial were those
of the 4 inch General Grant medal.
The blanks were submitted to pres
sure Of 1,000, 900 pounds, and the sec
ond pressure after the annealing of the
blank almost finished the medal. One
blank, upon which the pressure was ex-
erted three times ip succession, was
found to be more than was necessary.
The press is complete in detail and
symmetrical in design. It is an arch or
oval in form, the base and head being
heavy iron castings, the whole being
secured by two cast steel bands inches
thick and inches wide. These bands
were submitted to strain of 8, 900, 900
pounds each before being put in place.
The ram is located in the upper or head
casting and is placed in steel case. 1t
is 25 inches in diameter. and the maxi
mum pressure of 4, 900 pounds square
inch gives on this area the pressure of
2,O00 tons. There is graduated de-
viceattached by which any desired pres
sure can be secured and held for any
length of time. Experiments will soon
enable the person in charge Of the press
to determine the amount of pressure re-
quired for the various sizes of medal.
The movement of the ram up and
down is simply by the pressure of the
oil from the tank, situated about Is feet
above the room, the maximum pressure
being supplied by thin throw pump
and is only exerted during about the
last half inch of the stroke of the ram.
The power to drive the pumps is sup
piled by means of ~ horsepower
Eddy electric motor of slow speed
type. For the annealing of blanks there
is small gas oven, and it is very salts
factory. It has been demonstrated by
the experiments already made that the
pressure Of 10000 pounds per square
inch is required to cause such metals as
gold, silver and copper to commence to
flow or become fluid. Very interesting
results are expected from the install
ment of this plant, which will add so
much to the advantage of the govern
ment.-Philadelphia Telegraph.
The Skull Attributed to sophocles.
The supposed skull Of Sophocles found
by Munster in tumulus II stadia from
Dekeleia has now been examined by
Professor Virchow Of Berlin. The skull,
it may be remembered, was taken from
the skeleton Of very old man, with a