Method and apparatus for making a screw having variably canted threads

Abstract

A cutting device and method for its operation are utilized to apply variably canted threads to a screw blank. A conventional cutting lathe is provided with a conventional hydraulically operated adjustable cutting support attached thereto. A guide plate is generally mounted upon the lathe adjacent the armature, which is guided therealong to produce a particular pattern in the workpiece. The armature is pivotable to permit cutting at particular angles into the surface of a workpiece. A secondary guide is utilized in producing a controlled variable pivot of the cutting armature during its progression along the body of the workpiece. The secondary guide is rigidly mounted to the adjustable cutting armature and precisely controls its movement during the cutting operation, producing a cutting operation having dual movement characteristics. The cutting armature is moved longitudinally along the axis of the workpiece which simultaneously rotating about its pivot point to create a change in cutting angle over the length of this screw blank body. In order to produce the variably canted threads on a screw body having a tapered core, a preliminary cutting operation is first performed on the screw blank according to the traditional operation of the adjustable cutting support in which the cutting depth of the armature is changed over the course of the cutting operation. This preliminary cutting step permits the combination of the tapered core of the screw body and the variably canted threads.

Dependencies are inferred from the claim text.