Definizione

• Roller Die.  (1) A die engraved on the curved surface of a cylinder which is rolled over metal strip under pressure impressing a coin design on the sheet metal, which is blanked afterwards. First created in 1551, in Augsburg, Germany, by Kaspar Goebels, the process spread to other parts of Europe with very mixed results. The process was called taschenwerke and the roller mill was termed the walzenwerke. A larger coin could be made by this method in contrast to stamping a blank in a press. It's shortcomings, however, was the edges of the coin after it was trimmed or blanked from the strip, it had striations on the edge and burrs on one side. These had to be smoothed by hand.
  A mint technician, Nicholas Briot (1580-1646), tried to introduce this process first at the Paris Mint (1637), then at the Royal Mint London and was rejected at both mints. After he was accepted as mintmaster at the Edinburgh Mint in Scotland he introduced the roller die process and produced coins there but the process was shortlived.
  The process was tried for an issue of tokens by Lord John Harrington of Exton. He was issued a patent of James I in May 1613 to manufacture tokens (numismatists call these “Harrington farthings”). The process would place the image on strips of metal and blank individual pieces afterwards; some of the strips still survive. What makes this interesting for collectors is that the Duke of Lennox issued the same design farthings in diestruck pieces.
  The same process was tried to be reintroduced with 20th century technology by General Motors. An experimental press and extensive tooling was created, but in all testing it proved unsuccessful. In practice the process heated up the dies which failed.
  References:                                                                                                                            
  C4     {1840} Bolzenthal.
  C60   {1969} Jensen.
  C70   {1984} Kolb.
  C71   {1988} Cooper, pp 40-47, Chapt 7, 61-72.
  NE44 {1984} Junge, p 216.

  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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