Definizione

• Segmented Collar.  A mechanical device of several parts to impart raised letters or raised ornamentation on the edge of a struck piece. The collar is made in 3, 4 or 6 sections (3 being most common) with incuse ornamentation or lettering on the collar wall (the restraining surface inside the aperture). The sections are assembled and held in place by a retaining ring within a collar plate. The obverse and reverse dies come together inside the collar aperture. When struck the metal from the blank spreads in all directions filling the cavities in the die and up against and into the cavities of the collar.
  Edge lettered coins.  Coins with ornamentation in raised (or sunken) relief appeared as early as 1685. Jean Castaing developed this process at the Paris Mint where he forced the blank to roll between two engraved bars with a grove in the center. The ornamentation was engraved sunken or raised into this grove. The coins were struck after this was applied to the blanks.
  It wasn't until 1783, when Jean-Pierre Droz created the process, again at the Paris Mint, where edge ornamentation or lettering was formed at the same time the coin was struck on the screw press. This was the segmented collar Droz called virole brisée. Droz carried this technology with him when he was hired by Matthew Boulton at the Soho Mint, in Birmingham, in 1789. The production for coins was slow and only infrequently employed.
  Edge lettered medals.  A planchet or preformed blank – or partially struck up
  medal – is inserted within the assemblage, as laying it on the lower die. With the blow of the press the metal expands in all possible directions; it takes the form of the obverse and reverse die designs, filling each of their cavities as much as possible; plus the metal flows outward between the dies (much like flash between open face dies). This expansion also fills the lettered cavities of the segmented collar sections and forms the raised lettering on the edge.
  The assemblage has to be broken apart after every blow to be ejected, and the collar reassembled and placed in its collar plate for each subsequent blow, or to repeat the process for the next piece. Thus it is impractical for long production runs, and is usually reserved for exotic medals requiring raised relief lettering on the edges. The tooling and additional press time makes this an expensive procedure.
  Raised edge lettering formed by the segmented collar is in contrast to sunken edge
  lettering which was applied, formerly, with the use of the Castaing machine, or in modern times by the roller die. Such sunken lettering can be applied before the item is struck, or afterwards.
  History of the segmented collar.  There was a primitive form of segmented collar in use at the Paris Mint in 1550 under the direction of mintmaster Aubin Olivier, but this technology was lost when the moneyers fought the mint and reverted to hammer coinage in 1585. The segmented collar was reinvented and perfected by Jean-Pierre Droz (1746-1823) for use on the screw press at the Paris Mint in 1783.
  Droz, a Swiss engraver who had great mechanical skill, was hired away from the Paris Mint by Matthew Boulton in 1789 to provide technical expertise for Boulton's new Soho Mint in Birmingham. Droz provided Boulton with this – and much other – coining technology while he was there but Droz was unhappy in England. He returned to Paris (1799), after which Boulton continued the use of many processes he had acquired from Droz.
  Boulton and Watt employed the segmented collar at the Soho Mint when required. Notably Boulton employed its use to create raised lettering on the edge of his famed medal, Lord Nelson Battle of Trafalgar Medal, 1805. From this early beginning, the knowledge of the segmented collar spread to other mints and medal makers of the world.
  The first use in the United States was at the Philadelphia Mint in 1907 with the striking of gold coins: the Saint-Gaudens designed eagles and double eagles. The first private mint use of segmented collars in America was at Medallic Art Company in 1915 with the striking of the American Academy of Arts and Letters Gold Medal by James Earle Fraser.
  The use of the segmented collar remains today as the most practical way to achieve raised lettering on the edge of a medal (despite its high cost). It is impractical for the production of coins.  See edge lettering and numbering, virole brissée.

  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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