Indian Head gold pieces was modified by Barber, was "worthy of J.J. Audubon". Dies for the half eagle were sent to the mints in Denver and San Francisco; both western mints reported difficulties in striking the new pieces. Landis wrote to his counterparts at the other mints, advising them that the planchets, or blanks, needed to be shaved very slightly to strike properly. The new coins proved to be thinner than earlier coins of their denomination, due to the field being raised above the design. This meant that automated sorting machines could not reliably sort them when mixed with earlier coins. The new gold
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