Machining apparatus and method

A pair of grinding wheel carriages, each carrying its own grinding wheel, are both carried by a grinding machine to one side of a work carriage and workpiece when carried thereby. The workpiece is, in this instance, a camshaft with multiple pairs of similar cams disposed along the axis of the workpiece. The operation control and disposition of the grinding wheels provides for use of either grinding wheel to grind cam pairs or both grinding wheels to simultaneously grind a pair of cam pairs. The method involves first grinding a first cam pair of spaced but in phase cams with one of the grinding wheels; thereafter utilizing both grinding wheels simultaneously to grind two pairs of spaced cam pairs and repeating this step depending upon the number of cam pairs, lastly the final pair of cam pairs is ground utilizing the other grinding wheel. Workspeed for the camshaft is varied depending upon the cam region being ground and to accommodate grinding two cam pairs where the phase angle of one cam pair differs from the phase angle of the other cam pair.