Converts electric motor to Grinder or Buffing machine. Fits 5/8" Motor Shafts. Converts 5/8" motor shaft to 1/2" Threaded shaft. Holds Grinding wheels, Wire wheels or Buffing wheels with 1/2" hole. Wheel Widths Up To 1 1/16 in. O.A.L. 3.50 in. Washer Dia. 1.625 in. Lock on to motor shaft with 2 hex set screws. 1/2"-20 Right Hand thread. .