Abstract: An indexing head has a plurality of co-axial discs rotatable relative to each other. A first disc carries an indexing pin receivable in a series of equi-angularly spaced recesses of a second disc. A third disc is angularly settable relative to the second disc by means of gauge blocks, and is lockable after setting by locking means. A tool shank can be releasably held in an axial bore of the first disc. When used in an oil bath of an erosion machine, the head is fitted with a bellows skirt to prevent the oil reaching the discs.

Abstract: An indexing head has a plurality of co-axial discs rotatable relative to each other. A first disc carries an indexing pin receivable in a series of equi-angularly spaced recesses of a second disc. A third disc is angularly settable relative to the second disc by means of gauge blocks, and is lockable after setting by locking means. A tool shank can be releasably held in an axial bore of the first disc. When used in an oil bath of an erosion machine, the head is fitted with a bellows skirt to prevent the oil reaching the discs.

Abstract: A clamping and dividing mechanism for the precision machining of workpieces, for example annular cylinder grooves of ball races and the like, on a machine tool having a rotatable workpiece receiver, a counter support and a workpiece holder therebetween, the mechanism comprising various elements associated with the just-mentioned basic parts of the machine tool, namely: parallel, resiliently guided cylinder members in the receiver, assigned to a generated ball surface of the workpiece and aligned with a surface of the latter; an insert in the support, having at least two jaws facing the workpiece and engaging the same; means for guiding the holder in bores provided in the receiver and the support, respectively, in the form of two opposed swivel axles; and a trunnion associated with the holder, perpendicular to the direction of machining, and provided with support surfaces for the workpiece, that are parallel with the direction of machining.