Coining press


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 They were made of cast iron. The basic elements are:
  • A triumphal arch with a built-in base
  • A vertically arranged leadscrew that supported an inertia wheel or more commonly, a piece made up of two radial arms with weights at the ends.
  • The leadscrew rotates inside a threaded nut. The nut is attached to the structure. The turn of the inertia wheel determines the rotation of the thread bar and its vertical displacement.
  • Vertical guides allow vertical displacement of the holder without rotating.

Operation

Each coin is formed in a single operation. The press holds two negatives The body 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 no heat is applied.

History

Before the press, coins were minted with a hammer: