Countersunk screw

摘要

A countersunk screw has a large number of grooves (14) on the underneath of its screw head (11), which grooves (14) extend from the screw shank (12) to a cylindrical outer surface (20) directly underneath the top (13) of the screw head (11). The grooves have a depth which increases against the rotation direction of the screw, the groove boundary surface (18) in each case forming a cutting edge (22) on the deepest side of the groove (17). The cutting edges (22) and the grooves (14) are provided distributed uniformly over the circumference. <IMAGE>