Centerdrill - Expansion Males

In the thread opening by conformation with centertap, the advantages of drilling and flow forming are applied consistently. 

This is a non-chip removal process where the material flows from the base of the thread and is moved towards the ends. The principle is similar to the external thread rolling. Due to the compression of the material on the flanks of the thread, the tensile forces of the shaped threads are greater than in the cut threads.