Self-tapping screw with constant dia. shaft - has elliptical or oval pockets underneath screw head with cutting edges

摘要

The longitudinal axis of the pockets (10) extends tangentially to an imaginary circle coaxial with the screw shaft centre axis under the screw head. The circle extends centrally between the alignment (11) of the shaft (2) and the outer circumferential line (12) of the head. The edges of the pockets are formed as sharp cutting or milling edges which have a concave groove. The pockets are pref. narrow at the front in the turning direction (13) of the screw and wider at the back. USE/ADVANTAGE - For self-tapping and cutting screws for window strips, without the need for predrilling,or danger of splitting.