Coining machinery for the Mint of Rome
A stamping press and a cutting press to make perfectly round coins
This sheet designs machinery for the Mint of Rome (Zecca di Roma). A stamping device, which can also work without a spring provided the upper die stays joined to the moving sheath, underlies Leonardo's rule that only coins with a complete circle be accepted as good. Strips (laminae) drawn through a single draw-plate are punched into round blanks in the manner of a chestnut sieve and then struck. A separate cutting press, its hollow slightly wider at top than bottom, cuts blanks of perfect roundness, thickness and weight, sparing the labour of hand-cutting and weighing so the work passes only through the wire-drawer and the stamper.
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Stamping press and the rule of the whole circle
The mechanism can work without a spring so long as the upper die stays joined to the mobile sheath. Only coins with a complete circle are good; to achieve this, strips of one perfect width and thickness are drawn through a single draw-plate and the round blanks punched out like a chestnut sieve, then stamped.
Cutting press for coins of exact roundness and weight
The hollow of the die is made uniformly and imperceptibly wider at the top than at the bottom. This press cuts coins of perfect roundness, thickness and weight, sparing the man who cuts and weighs, so the work passes only through the hands of the wire-drawer and the stamper and yields most beautiful coins.
