Self-tapping or thread-forming screw

摘要

An improved self-tapping or thread-forming screw where the thread configuration on the screw end swages or forms the thread in an object to be threaded rather than cutting and removing a portion of the material of the object. The screw is provided with a threaded shank terminating in a tapered thread-forming end having four equi-spaced flattened surfaces separated by four threaded lobes or corners, and each corner is provided with a leading flattened surface in place of a portion of the radius to provide a partially threaded relief area in addition to the full relief areas formed by the flattened sides.