The turret lathe and automatic screw machine in their various forms have been developed and improved with the objectives of producing machined parts more rapidly and accurately at lower cost. On most machines of this type, the power available at the spindle has been greatly increased to take advantage of better cutting tool material. Mechanical power, in electrical, hydraulic or pneumatic form, has replaced human muscle power for such functions as feeding tools, operating chucks or collets and feeding bar stock in the machine.