Milled coinage in 1890. In modern practice in the United States, milling, or a milled edge, can refer to the raised edge on the coin face, applied by a special milling machine after the planchets are cut out and polished. In addition, the reeding of coins of higher value, applied by the collar holding the coin when it is stamped, can be considered part of the milled edge. Milled coinage In numismatics, the term milled coinage (also known as machine-struck coinage) is used to describe coins which are produced by some form of machine, rather than by manually hammering coin blanks between
Metal spinning attached. In CNC applications, carbide or tool steel cut-off tools are used. The mandrel does not incur excessive forces, as found in other metalworking processes, so it can be made from wood, plastic, or ice. For hard materials or high volume use, the mandrel is usually made of metal. Several operations can be performed in one set-up. Work pieces may have re-entrant profiles and the profile in relation to the center line virtually unrestricted. Forming parameters and part geometry can be altered quickly, at less cost than other metal forming techniques. Tooling and production costs are also comparatively low. Spin