Locking screws

Small flanks of 30º are rolled on to the normal thread flanks of 60º which extend beyond the nominal diameter of the bolt thread. When screwed in the 30º points penetrate in to the counter-thread (ISO tolerance zone 6H) causing the screw to lock and provide a fit that is said to be resistant to oscillation and vibration. "The deformation of the nut thread by the 30º point takes place within the flexible part of the screw which ensures a high degree of self-locking and reusability of the screw of up to five times in the same nut thread. Longitudinal and lateral movement between the screw and the mother thread are impossible and there is no subsidence, even with ductile materials." The screws are described as fastening and locking elements in one and, therefore, can replace mechanical and chemical lock-retention methods. Fully automatic assembly and mounting is stated to be possible because no coiled-up locking elements are present to cause problems by jamming.