A most remarkable double air bearing spindle, with a central variable-speed motor, is used to rotate the diamond. The massive table floats on an air film. When all goes well the thirty-six faces are flat to at least a quarterwave and all angles to 5 sec of arc or better.
© 1978 Optical Society of America
Frank Cooke, "To make an aluminum polygon," Appl. Opt. 17, 6-6 (1978)