diamond turning is a rapidly developing technology being utilized to produce both large and unique optical reflectors in a cost effective manner. the process is especially suited for the high reflectivity metals such as copper, gold, silver, and aluminum. the basic requirements include a single-crystal diamond tool, a high quality and compatible part material, a nondistorting part support technique, the control or compensation of environmental influences, and a machine tool specially designed for super precision tool path control and low vibration. the capabilities of the advanced machine systems developed in the oak ridge y-12 plant include a broad range of shapes and sizes. flat or curved reflectors up to 24 inches in diameter have been machined with better than 40 microinch figure accuracy and 2 microinch surface finish, while reflectors up to 78 inches in diameter have been machined with 75 microinches figure accuracy and 3 microinch surface finish. the efficiency and capability of this process to produce large numbers of complex reflectors or precision masters for replication may make it useful in the manufacture of reflectors for future solar energy concentrator systems. (era citation 03:011949)