Abstract: An indexable revolving turret has a rotary tool carrier which is movable to a plurality of angularly spaced indexed positions, and an indexing shaft which is connected with the tool carrier for indexing the same to the respective ones of these positions. Cooperating spur gears are provided on the tool carrier and on the housing and become disengaged preliminarily to indexing of the tool carrier. A control shaft is driven by a drive so as to be rotated by the same and transmits motion to a Maltese-cross drive, an input member of which is mounted on and rotatable with the control shaft. The indexing shaft can be moved axially of itself, thereby moving the tool carrier into and out of indexing position, and for this purpose a cam drum is mounted on the control shaft and the cam follower slides in a cam groove of the cam drum and is connected with the indexing shaft so as to move the same into and out of an indexing position, depending upon the angular position of the cam drum.

Abstract: A machine tool wherein the carrier for several rotary work spindles is separably mounted on a base in such a way that the chucks of two spindles are spaced apart by equal distances from horizontal ways for two side slides each of which mounts a carriage for an indexible tool turret. If the treatment of a workpiece at one of the working stations takes up more time than the treatment of a workpiece at the other working station, the tools which have completed the treatment of a workpiece at the other station are moved to the one station to cooperate with the other tools in rapidly completing the treatment of the workpiece at the one station. The carrier may be a box-like structure with two spindles or a drum having more than two work spindles and being indexible in a headstock, which is separably secured to the base.