Coining. Made by stamping under pressure between dies, on planchets or blanks prepared in advance by upsetting. Blanks are not heated (as in forging) but are cold coined at room temperature. Coining dies are low relief to create the design in one blow; as coining is intended for rapid production run. Care is taken in the preparation of the dies; they are extremely accurate, highly detailed and heat treated to sustain pressures higher than other metalworking process.Coining is one of many of metalworking processes; it is noted for the highly detailed design that can be imparted to workpieces of small size and can maintain this detailed design reproduction for long production runs. In coining, dies transmit their design by flow plasticity, surface metal flows into the cavities of the dies with no intention of effecting the substrate metal of the blank. Coining is obviously how coins, tokens and small medals are made, but coining also includes the manufacture of other items ranging from small parts, gears, wheels and buttons, to silverware.
excerpted with permission from
An Encyclopedia of Coin and Medal Technology
For Artists, Makers, Collectors and Curators
COMPILED AND WRITTEN BY D. WAYNE JOHNSON
Roger W. Burdette, Editor