US Patent 7850409 Fastening element

A fastening element has a shaft (12), and a tapping thread (21) carried by the shaft (12) and having at least one screw thread (22, 42) a section (23; 43) of which that adjoins the thread pilot (35), having a plurality of following one another thread steps (24, 25, 26, 27; 44, 45, 46, 47) having different cross-sections, with a cross-section of the at least one screw thread (22; 42) decreasing stepwise toward the thread pilot (35) from a thread step (24, 25, 26, 27; 44, 45, 46, 47) to a thread step (24, 25, 26, 27; 44, 45, 46, 47), with the thread steps (24, 25, 26, 27; 44, 45, 46, 47) having respective cutting edge-forming end surfaces (28, 29, 30, 31; 48, 49, 50, 51) aligned, at least partially, in a direction of the thread pilot (35).