Method and apparatus for controlling the operation of a grinding machine of the type comprising a circular grinding wheel adapted to rotate about its axis and a spindle adapted to hold a workpiece at a position radially spaced from the grinding wheel. The grinding machine includes slide means for advancing the grinding wheel into the workpiece, such means being powered by a threaded shaft and boss arrangement, and "jump-on" gauge means for measuring the diameter of the workpiece and providing an electrical output signal which is used to control feedrate. Feedrate is determined by a microprocessor which is connected to receive the gauge signal and to produce a feed program which will produce a given final diameter in a given time.