A self-tapping screw is a threaded fastener capable of forming its own threads; its thread cross-section features a specialized profile, such as a trilobular or pentagonal shape. Its operating principle involves forming internal threads within a pre-drilled plain hole through cold extrusion, thereby achieving an interference fit without the need for a pre-tapped hole.
While the thread profile of this screw is identical to that of standard threads, its effective diameter is larger; furthermore, it features a tapered pilot section at the tip, and its shank possesses a curved triangular cross-section. This type of screw not only offers anti-loosening properties but also eliminates the need to pre-tap holes in the workpiece. It presents numerous technical and economic advantages, including the elimination of the tapping process, reduced production costs, improved operational efficiency, superior preload force and vibration resistance, and a reduced required tightening torque.
