The invention relates to a process and a device for machining of workpieces (10) like crankshafts or similar components which are rotated about their own axis during machining, at least two mutually independently operating rotary milling tools (15, 16, 21, 22) performing material-removing operations simultaneously at different points on the workpiece. In order to maximize the edge life of the tools used, with special regard to the most uniform wear possible on all the rotary milling tools, it is proposed that the rotation speed of the tools be matched or varied to provide an optimum cutting operation and the rotation speed of the second and any other rotary milling tool be controlled dependently upon the tool rotation speed predetermined by the matching or variation.