Abstract: The present invention provides an improvement (20) in a Davenport® automatic screw machine having a stationary spindle. The improvement broadly includes a quick-change mechanism (26) associated with the stationary spindle (22). The mechanism includes mating frusto-conical first and second surfaces (28, 31) on the spindle and tool holder, and a multi-lead threaded connection (32) between the tool holder and stationary spindle such that the tool holder may be quickly locked into mating engagement with the stationary spindle by relative rotation therebetween through a short angular distance. The invention may also include an adjustment mechanism (33) that allows the axis (x2-x2) of the tool to be aligned with the axis (x1-x1) of a spaced rotatable spindle. This adjustment mechanism includes a base member (34), an adjustment member (35), and a locking mechanism (37) for selectively holding the adjustment member in the desired position relative to the base member.

Abstract: The invention provides an improved method and apparatus for indicating an apparent error in the operation of a fluid-powered attachment (A) mounted on a machine tool for controlled movement toward and away from a workpiece (W) upon which an operation (e.g., thread rolling, knurling, burnishing, etc.) is to be performed during a cycle.

Abstract: A thread rolling attachment (50) is adapted to be mounted on a machine tool and to be selectively moved in an axially direction relative to a workpiece (W) having a cylindrical surface upon which a thread is to be rolled.

Abstract: The invention provides an improved method and apparatus for indicating an apparent error in the operation of a fluid-powered thread-forming attachment (A) mounted on a machine tool for controlled movement toward and away from a workpiece (W) upon which a thread is to be formed during a thread-forming cycle. The improved apparatus (60) broadly includes a fluid-powered actuator (64) for selectively moving the thread-forming attachment (A) relative to workpiece (W) during the cycle; a sensor (73) operatively arranged to monitor the pressure within the actuator during at least a portion of the cycle, and arranged to provide an output signal; and a programmable logic unit (75) provided with the sensor output signal, arranged to store minimum and maximum permissible fluid pressure values expected during the cycle, and operatively arranged to indicate an apparent error in the formation of a thread on the workpiece if the pressure determined by the sensor is not between the stored minimum and maximum values.