What are the structural elements of self-tapping screws?


From head to tail, the self-tapping screw is composed o […]

From head to tail, the self-tapping screw is composed of three parts: the head, the shaft and the end of the shaft. The composition of each self-tapping screw has four major elements: head shape, screwing method, thread type, and end type.
Head shape-various head shapes. There are round head (half round head), oval head, round head flange (with pad), oval head flange (with pad), pan head, pan head flange (with pad), countersunk head, semi-sunk head, Cylinder head, spherical cylinder head, horn head, hexagon head, hexagon flange head, hexagon flange (with gasket), etc.
Twisting methods-There are various ways of twisting. Outer wrenching: hexagon, hexagonal flange, hexagonal flange, hexagonal flower shape, etc.; inner wrenching: flat groove, cross groove H type (Phillips), cross groove Z type (Pozidriv), cross groove F type (Frearson) , Square slot (Scrulox), compound slot, internal spline, internal hexagonal flower shape (quincunx), inner triangle, inner hexagon, inner 12 corners, clutch slot, six-blade slot, high torque cross slot, etc.
Thread types-there are many types of threads. There are self-tapping threads (wide thread), machine threads, dry wall screw threads, fiberboard screw threads, and other special threads. In addition, threads can be divided into single-lead (single-end), double-lead (double-end), multi-lead (multi-end) and high-low-thread double-end threads.
End type—The end type mainly includes saw end and flat end. However, grooves, grooves, incisions or drill-like parts with cutting functions can be machined according to the function of use. In some standards, the same saw end or flat end, but also different forms.
From the above introduction, it can be seen that there are various changes in the shape of the head of the tapping screw, the way of screwing, the type of thread and the type of rod end. They can be combined with each other to release many different products that belong to the category of self-tapping screws.