page_title: Castaing machine
section_title: Operation
hierarchical_section_title: Castaing machine / Invention / Operation
caption_attribution_description: English: 1794 1C 'Venus Marina' (S-32) edge lettering (460-2034)
context_page_description: The Castaing machine is a device used to add lettering and decoration to the edge of a coin. Such lettering was necessitated by counterfeiting and edge clipping, which was a common problem resulting from the uneven and irregular hammered coinage. When Aubin Olivier introduced milled coinage to France, he also developed a method of marking the edges with lettering which would make it possible to detect if metal had been shaved from the edge. This method involved using a collar, into which the metal flowed from the pressure of the press. This technique was slower and more costly than later methods. France abandoned milled coinage in favour of hammering in 1585.
  England experimented briefly with milled coinage, but it wasn't until Peter Blondeau brought his method of minting coins there in the mid-seventeenth century that such coinage began in earnest in that country. Blondeau also invented a different method of marking the edge, which was, according to him, faster and less costly than the method pioneered by Olivier. Though Blondeau's exact method was secretive, numismatists have asserted that it likely resembled the later device invented by Jean Castaing.
context_section_description: An 1819 account described the operation of Castaing's machine: 
  The machine used for this purpose consists of two plates of steel in form of rulers, on which the edging is engraved, half on the one, and half on the other. One of these plates is immovable, being strongly bound with screws to a copper plate on a board or table; the other is movable, and slides on the copper plate by means of a handle, and a wheel, or pinion, of iron, the teeth of which catch in other teeth, on the surface of the sliding plate. The planchet, being placed horizontally between these two plates, is carried along by the motion of the movable one; so as by the time that it had made half a turn, it is found marked all round.
  According to a 1765 Encyclopédie entry, Castaing's machine was capable of applying the edge lettering to 20,000 coins daily.
  The machine came into use at various mints throughout the world as a way to improve upon the existing machinery used for edge lettering. A copy of Castaing's machine was put into use at the British Royal Mint, and in 1792, the director of the newly established United States Mint in Philadelphia, David Rittenhouse, ordered three coinage presses from England 
  to which he added a modified version of the machine. This became obsolete following Franklin Peale's introduction of steam-powered equipment to the Mint in 1836. Castaing's machine was replaced at the Paris Mint in 1803, when one of the Mint's engineers, Philippe Gengembre, created his own version.
caption: A portion of the edge lettering on a 1794 United States Liberty Cap large cent, applied by the Castaing machine
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