Abstract: An apparatus for compensating for deviations in the straightness of the bed of a machine tool including a wire means providing the reference of straightness. In one embodiment, a wire means is tautly mounted along the bed and submerged in oil to help prevent vibration of the wire means to increase the accuracy of the machine tool. A sensor is mounted to the carriage of the lathe and senses the position of the wire in the oil bath and signals a motor means to adjust the position of the machine tool according to deviations in the straightness of the bed.

Abstract: A screw for use in a thermoplastic extruder. A plurality of recessed pockets and/or raised lobes are in the screw shaft and these operate as the shaft is rotated to constantly shift the melted and unmelted portions of the plastic resin radially inwardly and outwardly within a pitch length of the screw inside the extruder to quickly and uniformly mix the plastic into a homogeneous melt.