Abstract: A rotatable shaft positioning mechanism is disclosed for use with a multiple spindle automatic machine tool having a plurality of rotatable spindles in an indexable spindle carrier. A Hall effect sensor is actuated by a permanent magnet rotating with each spindle to develop a reference signal which starts a counter counting pulse generated by a pulse generator connected to the output of a stepping motor. The stepping motor is connected to rotate the spindle and when the counter counts out, the spindle is stopped at the preset position. The spindle is held in place and the machine tool may be operated for performing a machining function on a workpiece held in the spindle, for example, a cross drilling attachment, cross-tapping attachment or alternatively, the spindle may be rotated at a slow speed by the stepping motor to perform a contouring or assembling operation on a workpiece in the spindle.