Q. David Bowers
After the die comes from the lathe it is carefully finished off by hand, and when all polished is a beautiful piece of work. It is still very soft, requiring to be hardened before it can be used, which is done by heating it very hot, and holding it under a stream of water until cold. The relief is exactly like the coin-that is, the device is raised as in the coin. It will not do to use this in stamping, as it would reverse the appearance on the coin. Therefore this "hub," or "male die," as it is named, is used only to make other dies.
Round pieces of very soft steel, a little larger than the die, are smoothed off on the top, the centre being brought to a point a little higher than the sides. It is placed on a solid bed, under a very powerful screw-press, and the hub placed on top of it -the centre of the hub on the point of the steel, like a seal on the sealing-wax. The screw is turned with great force by several men, and presses the hub a little into the steel. It is necessary to have the steel higher in the centre, as if the centre impression is not taken first, it can not be brought out sharp and distinct. The steel is softened again by being heated and allowed to cool slowly, and the operation is repeated. This is done several times, until the whole impression is full and distinct.
If there is any little defect it is rectified with the engraver's tool. The surplus steel around the edge is cut off, and the date put in by hand, when it is hardened and ready for use. The date is not cut on the hub or on the first die-which is called "female" -as perhaps the hub will last for two years, and the date cannot be altered. This die is never used to stamp with, but preserved, so that if the hub breaks it can be used to make another. The dies for use are prepared in the same way. About 1,300 a year are made for the various branch mints, and those for the New Orleans Mint were sent on just before the state seceded, which the authorities have not yet had time to return. Sometimes a die will wear for a couple of days, and again they will break in stamping the first coin. Steel is treacherous, and no dependence can be placed in its strength. As nearly as can be ascertained their cost is $16 a pair.
The Coining Room
We will now enter the Coining Room, a light, airy hall, filled with brightly polished machinery, kept as clean as the milk-pans in a New England dairy. Jessie 'can handle it as freely as her fan without soiling her light gloves, or trail her dress over the floor without a misgiving. A passageway in the middle of the room is separated from the machines on both sides by a neat iron fence. The quantity of gold and silver lying about would make it unwise, especially in these times, to allow strangers to mingle among it. Visitors can see every thing from this passageway, but the pleasure of handling is denied.
There are two styles of coining presses, both working on the same principle, but some more compact and handsome than the others. They are the invention of Mr. Peale, the plan being taken from the French press of Thonnelier's. Peale's press works much more perfectly and rapidly, and is a vast improvement over the old-fashioned screw-press still used in England. It seems to be as nearly perfect as anything can be. In the engraving [accompanying the Harper's article here reprinted] we have given one of the old presses, as it is more open and exhibits better the working power. There is so little difference, save in form, that, essentially, they are the same. There are eight presses, all turned by a beautiful steam engine at the further end of the room.
The power of the press is known as the "toggle," or, vulgarly, "knee" joint, moved by a lever worked by a crank. The arch is a solid piece of cast iron, weighing several tons, and unites with its beauty great strength. The table is also of iron, brightly polished and very heavy. In the interior of the arch is a nearly round plate of brass, called a triangle. It is fastened to a lever above by two steel bands, termed stirrups, one of which can be seen to the right of the arch.
The stout arm above it, looking so dark in the picture, is also connected with the triangle by a ball-and-socket joint, and it is this arm which forces the end of the lever above by a joint somewhat like that of the knee. One end of the lever can be seen reaching behind the arch to a crank near the large fly-wheel. Now, when the triangle is raised, the arm and near end of the lever extend outward, as when one is resting his whole weight on one leg the other bends out at the knee. If the knee is drawn in and the leg straightened, the whole body will be slightly raised.
The press is on exactly the same principle. When the crank lifts the further end of the lever it draws in the knee and forces down the arm until it is perfectly straight. By that time the crank has revolved and is lowering the lever, which forces out the knee again and raises the arm. As the triangle is fastened to the arm it has to follow all its movements. Thus we have got the motion, which is all-important.
Under the triangle, buried in the lower part of the arch, is a steel cap, or technically, a "die stake." Into this is fastened the reverse die, or, according to boys' dialect, the "tail" die. The die stake is arranged to rise about the eighth of an inch, but when down it rests firmly on the solid foundation of the arch. Over the die stake is a steel collar or plate, in which is a hole just large enough to allow a blank to drop upon the die. In the triangle above the obverse die is fastened, which moves with the triangle; and when the knee is straightened the die fits into the collar and presses down upon the reverse die.
Just in front of the triangle will be seen an upright tube made of brass, and of the size to hold the blanks to be coined. The blanks are examined by the girl in attendance, and the perfect ones are placed in this tube. As they reach the bottom they are seized singly by a pair of steel feeders, in motion as similar to that of the finger and thumb as is possible in machinery, and carried over the collar and dropped upon the die. The knee is straightened, forcing the obverse die to enter the collar and press both sides of the blank at once. The sides of the collar are fluted, and the intense pressure expands the blank about the sixteenth of an inch, filling the collar and producing on the coin the fluted or reeded edge. It is put on to prevent any of the gold being filed away.
After the blank has been dropped upon the die, the feeders slide back on the little platform extending in front of the machine, in readiness to receive another. The knee is bent, which raises the die about half an inch above the collar. The die stake is raised at the same time, so as to lift the newly-born coin from the collar, and the feeders coming along with another blank, push the coin over into a sloping channel, whence it slides into a box underneath.
The pressure on the double eagle is about 75 tons; yet so rapid are all these complex motions that 80 double eagles are coined in a minute; and while the reader has been studying out this explanation probably 10 or 12 thousand dollars [of value of $20 pieces] could be struck on a single press. The smaller pieces, such as dimes and half dimes, are coined at the rate of 150 a minute. While usually only 75 tons pressure are applied, the large presses will stand a strain of 150 tons. Sometimes government and other large medals are struck, which require this heavy power.
It is a beautiful sight, as the bright glistening coins drop in a golden stream, with the peculiar metallic clink so pleasant to hear. It is as pretty a cascade as one often sees. Jessie remarked to one of the men that it must be exceedingly tantalizing to be handling so much wealth, yet to have so little of it.
"Why, we don't think nothing of this-we just kick it about like so much old iron; but when we get our month's pay in our pockets we feel rich, I-tell-you!"