Buttonhole screw with screw driver - has two or more holes punched out of side and has self cutting pins

摘要

The buttonhole screw with a screw-driver incorporates two or more punched-out parts to one side of the middle of the screw head which has no slit in it. The pins of the screw driver mill or cut with a supporting sloping cut (2), a plane cut, drilling cut as the screw head is recessed or they have a shorter cylinder pin. The screw driver's shaft has a hole in or narow part for fixing the shaft into a drilling-machine or into a handle. ADVANTAGE - The screw is self-cutting and is turned not by a slit in the head, which is absent, by two or more holes punched out in the side of the threaded shaft's axle.