A coining press is a manually operated machine that mints coins from planchets. After centuries it was replaced by more modern machines. Presses came in multiple shapes and with different accessories (to collect the coins, etc.) They were made of cast iron. The basic elements are: * A triumphal arch with a built-in base * A vertically arranged

leadscrew A leadscrew (or lead screw), also known as a power screw or translation screw,Bhandari, p. 202. is a screw (simple machine), screw used as a linkage (mechanical), linkage in a machine, to translate Rotation, turning motion into linear motion. ...

that supported an inertia wheel or more commonly, a piece made up of two radial arms with weights at the ends. * The leadscrew (male) rotates inside a threaded (female) nut. The nut is attached to the structure. The turn of the inertia wheel (or bar with weights) determines the rotation of the thread bar and its vertical displacement (up or down depending on the direction of rotation). * Vertical guides allow vertical displacement of the holder (upper die) without rotating.

Operation

Each coin is formed in a single operation. The press holds two ''negatives'' (molds that show each side of the coin) The body (material from which the coin is to be formed) is placed on the lower negative and the upper negative is lowered to create pressure sufficient to emboss the negatives onto the body. The upper negative descends directly without turning, pushed by a threaded bar that rotates, turned by a lever, compensated by an anti-torsion system. It is called a cold deformation as not heat is applied.

History

Before the press, coins were minted with a hammer:

Gallery

Museo Arqueológico Nacional - 1873-22-19 - Prensa de volante 01.jpg, General view Museo Arqueológico Nacional - 1873-22-19 - Prensa de volante 02.jpg, Detall File:Milling of coins.jpg, Die-mill. Ball radii sometimes measured almost 2 meters (<2m). File:Presse_au_balancier.jpeg, Nicolas Briot rocking press, c1626. File:Vista de la casa de moneda cantonal.jpg, Mint of Cartagena.Vista de la casa de moneda cantonal. Cartagena Ilustrada. Año 1874. Año III. Número 31. Página 123.
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References

Bibliography

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