The Screw Press – High Quality and High Anxiety

Hammer struck coins, as traditionally made, were inconsistently struck and not always perfectly round.

Less than honest people would clip metal from the edges of such coins. Clipped coins were then returned to circulation by the malefactors at full value, with the shavings retained as a profit.

And coin clippers were not the only ones made anxious by the new methods. Mint workers felt threatened by the new machinery, which was extremely productive at 30 to 60 coins per minute, and produced a superior product.

So what did a this new press look like, and how did it work?

Looking at the illustration at the top of this page, notice the two arms extending outward from the top of the press. Weights, often iron spheres, were attached to the ends of these arms, which were joined to a vertical capstan at the center. The capstan, supported in a framework, was threaded.

When the coiners spun the weighted arms in a circular motion, the threaded capstan was driven downward with considerable force. Dies at the end of the capstan and beneath the coin-to-be impressed the design into each side of the newly struck coin.

Though mechanized, this was a process still powered by human physical exertion. Furthermore, production of each coin still required the efforts of several individuals. The savings in labor accrued from the higher speed of production. Over time, a greater number of coins could be struck by fewer mint workers.

Implementation of the screw press began in Europe - first in France, then in England, later in Spain. The process reached the New World in 1732, as the first Spanish milled dollars were struck in Mexico City.

During the same period, a parallel technology was employed using the roller press, as discussed on the next page…

Next… Roller Presses

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