Catalogue description Royal Mint: Dies Matrices and Puncheons

Before the introduction of steel, the dies (or stamps) for impressing designs on coins were made in iron. The main design was cut by the engraver (sometimes described as the cutter of irons) onto a matrix. The matrices were used to produce punches or puncheons which were used by the Die Sinker or Sinker of Irons, later known as the Smith, to produce the working dies. During the seventeenth century it was the duty of the Keeper of the Dies to issue the dies to the Moneyers as often as coining and striking was required, and to recover them afterwards; and also to see that the hammermen struck the coin correctly. After the introduction of coining machinery in 1662, it was his business as Keeper or Clerk of the Irons to keep an account of all dies made and hardened by the Smith, and when the dies were worn out to see them defaced in the presence of the Warden, Master and Comptroller.

The office of Clerk of the Irons was combined with that of the Surveyor of the Meltings in 1744. In 1815, the office was combined with that of the Superintendent of Machinery. That combined office became the one office of Superintendent of the Coining and Die Departments in 1852. The Coining and Die Departments and the Melting Department were grouped together to form the Operating Department in 1870 under a single superintendent.