Définition

• EDM Dies.  Dies made – not by conventional machining or hubbing processes – but by electrical discharge machining (EDM). Such dies so made exhibit a micro pitting which imparts a pebbly texture to all items struck from that die. Such tiny pitting can be stoned or polished but not entirely removed, particularly in recessed design areas, a diagnostic for EDM forming of dies.

  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

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