GEWINDEFORMENDE SCHRAUBE.

摘要

The self-tapping screw has a head, a threaded shank, a guide portion of smaller dia., and a tapering portion joining the shank to the guide portion. The tapering portion joins to the shank and has a thread of the same pitch as the shank. It is formed by two opposite segments. The thread is formed only in the segment of a larger radius. The guide portion comprises a cylindrical boss (22), and the thread in the tapering (24) portion and the shank is of the twin-or multi-start type.