Thread Rolling
Triangular self-tapping screw, also known as Type TT (Type Tai still has a patent), is developed based on the principle of forming screw tapping. The thread is rolled into a self-tapping screw with a specially designed thread and end so that the screw can be intermittently Under pressure, it rolls itself into a matching female thread, and the material around the hole can more easily fill the space between the thread and the bottom of the self-tapping screw. Because its friction force is smaller than that of the thread forming self-tapping screw, it can be used in thicker On the material, the torque required for rotation is better controlled, and the combined strength is higher. The engineering standard definition of threaded self-tapping screws is higher and clearer than that of forming or cutting self-tapping screws in terms of material, heat treatment, and strength, making threaded self-tapping screws a true "construction" fastener
