Abstract: A device for clamping a crankshaft in a grinding machine has a rotary face plate which defines a lubricant-filled space and carries two parallel shafts for removable clamping jaws. The jaws can cooperate with a support, which is removably affixed to the face plate, to hold a crankshaft therebetween. The mechanism for pivoting the jaws toward and away from the support has a feed screw which is accessible from the outside of the face plate and extends into the space where it meshes with a nut which can pivot two bell crank levers in opposite directions. The bell crank levers are mounted on the two shafts, and those arms of the levers which must be pivoted by the nut in order to move the respective jaws toward the support carry pistons which deform packages of dished springs when the jaws bear against the crankshaft.

Abstract: A machine tool for maching of crankpins on crankshafts, or of similarly ts-axially offset portions of other types of workpieces, includes an arrangement for indexing the workpiece to a plurality of different positions to place new crankpins in position for machining without having to unclamp the workpiece or stop its rotation. Indexing accuracy is greatly improved and all indexing-related operations are powered by the prime mover of the machine tool rather than requiring separate drives.