A turning machine (40) includes a control and mechanism for positioning the turning tool (56) on the head. A CNC (58) issues command signals for selectively positioning the tool on the head (82). These signals are developed from an encoder (66) which provides the instantaneous position of the rotating part (42) being turned and from a program in the CNC containing information about the part. A closed loop control system (80) receives these command signals and converts same into a control current for a linear motor (72) which is the prime mover controlling the positioning of the tool on the head. The linear motor operates a carriage (128) on the head and the cutting tool (56) mounts on the carriage opposite the connection of the linear motor to the carriage. The carriage is a hollow bar guided on the head by sets of rollers which are cooperatively arranged to provide yieldably forceful constraint of the bar. The rolling action of the bar on the head provides a low friction, low inertia construction enabling rapid response to CNC commands. <IMAGE>
