The Washington times., 1901-09-29
How BULLION is COINED.
Process of Converting Gold anl
Silver Into Lawful Money
Delicate Machinery Required to
weigh, stamp, md Mill the Pre-
cfous Metals-Turning Out Eighty
Eagles Per Minute in Philadelphia

The process by which the ore from the
mine is changed into new and glittering
coin is long and tedious. The ore as it
comes from the ground must first pass
through the smelling process. by means
of which the metal is extracted and con-
verted into bars of gold or silver. the
methods naturally varying. according to
the character of the ore and the locality.
Seine idea of the enormous amounts that
have been handled by the various mints
and assay offices is shown by the state
ment that 81 99s. 732, ,252.Z7 represents the
total amount of coinage of the various
mints of the United States from the es-
tablishment of the Philadelphia Mint to
the end of June. 1890. OF this great
amount the total silver, $7s6. III. .l59. 55. and
the total minor coinage amounted to
sSS. sos 9e9.7 The bars of gold or silver,
known as bullion" are CAREFUL assayed,
either at the Mint or at one of the assay
offices in New York city, Helena, Mont,
or Denver. Col. and from these the coins
are made. The first step consists in pre-
pairing an alloy for coinage of the refined
gold or silver, which is nearly pure. with
copper. and this Is accomplished by weigh
ing out quantities of gold and copper or
silver and copper, which are then melted
to5ctHeI III leau-Dl1Ck
and after the molten metals are thorough
ly mixed they are poured into cast-iron
molds to produce rectangular bars called
'ingots.' which vary in size, according
to the denomination of the coin for which
they are intended. Thus, the ingot for
the double eagle is 12ss inches long, "
inch thick. and ~ inches wide. and
weighs so ounces, while the ingot for the
I ig u
thick. and IFS inches wide.
The ingot is then passed between heavy
rolls from which it issues in long narrow
strips. This operation Is called break
ing down. and makes the metal hard
and springy, and If continued would cause
1t to crack and split. In order to prevent
this the strips are annealed by being
heated In furnace to about 1,500 degrees
Fahrenheit, where they remain for about
an hour and half, according to the heat
of the furnace and the SIZE of the strips.
They are then cooled il water and each
strip wiped dry, after which they are
finally passed through the rolls. Double
eagles and eagles pass through the
finishing rolls three times, while half
and quarter eagles must go through at
least four times. The strips are again
annealed. cut in two. for convenience in
handling, taken to the pointing rolls SO
that an inch and a half OF the end may
be pointed or flattened. and creased with
tallow to permit their easy passage
through the dies of the drawbench. The
drawbench consists of two independent
sections, each of which has two dies reg.
ulated by set-screws,s and between these
dies the pointed end of the strip is pass
ed. being seized by the jaws of the car
r Ia GO n 1rpv hxy nf
cnain, which reduces the strip as nearly
as possible to standard weight, This is
ascertained by weighing sample blanks or
pianchets that are cut from either end.
When the strips are deemed Of proper
weight they are taken to the cutting
shears and the pointed ends cut off, after
which they pass to the cutting press,
where. by means of a steel punch work.
ing into a matrix, the planchets are cut
therefrom. These blanks are then taken
to the washing room, where they are
cleansed from grease by washing in lye
composed of soap, borax and water. Aft
er rinsing in clear water they are dried in
q large copper pan heated by steam. They
are then carefully examined on the
lecting table and all perfect blanks sepa-
rated from the imperfect ones. and, in
the case of gold coins, must have the fol-
lowing weights: Double eagle 5l6
grains; eagle" 25S grains; half eagle
129 grains. and quarter eagle" 6i.5
grains. although allowance of half
grain is permitted in the case of the ''dou-
BILE eagle and eagle" and a quarter
grain in the "half' and quarter eagle"
This weight is determined in the adjust
ing room. where each piece is placed upon
the balance, and. if heavier than the limit,
is reduced by fling its edge, whereas. If
lighter, il is condemned and returned to
the smelter The accepted planchets are
then taken to the milling machine. where
the raised edge. technically called mill
ing is put on them.
The machines known as milling ma
chimes are simply uasetting devices. and
the former designation often misIeads one
not familiar with minting processes. We
illustrate the latest type, which has just
been installed. Its duty is to upset the
blank after it leaves the cutting press by
passing the piece between a segment and
a revolving disk, shown at the extreme
upper left-hand corner, just below the
feed tube Grooves are cut in the disk
and segment by a sharp tool, and the
shape of the grooves has been the subject
of considerable experiment in order to
give as square an edge as possible to the
finished coin without producing a fin. 1t
is driven by a three-horse power COM
pound-wound motor running at $40 revo-
lutions per minute, and transmits rotary
movement to the disk through back-gears
The disk runs at 90 revolutions per min
ute. The blanks are fed by the operator
into the tube and are pushed against the
disk by a small feeder, and the friction
on the disk carries the blank around the
inside of the segment and then it drops
into a box. This upsettirg machine will
upset 575 half dollars per minute, and the
machines for other denominations will
turn out proportional amount. Nine of
these machines, excepting the motor,
were designed and built at the United
States Mint, and it is the intention of the
authorities to gradually work into the
designing and building of several special
machines for coming operations
The advantage of the milling process Is
that it protects the surface of the coin
from abrasion. The milled pieces must be
again cleaned and softened, which is ac-
complished by annealing them at a cher
ry-red heat. after which they are dipped
into n solution of sulphuric acid and wa
ter sufficiently strong to clean and bright
en- them. They are then rinsed in boiling
water and shaken in sawdust to dry them,
after which they are ready for the stamp
ing press Before stamping a brief de-
scription of the die Is necessary. The de-
sign being selected. a drawing is made
the exact size of the coin required, and
from this drawing a tracing is taken for
the purpose of transferring he design to
the die. This is accomplished by cover
ing the surface of the die, which has pre-
t.Zf.r ,t.;tH ",