From beginning to end, the tapping screw is composed of three parts: the head, the rod and the end of the rod. The composition of each self-tapping screw has four major elements: head shape, screw mode, thread type and end type. Head shape - There are a variety of head shapes. There are round head (half round head), flat head, round head flange (with pad), flat head flange (with pad), pan head, pan head flange (with pad), countersunk head, semi-countersunk head, cylindrical head, spherical cylinder head, horn head, hexagonal head, hexagonal flange head, hexagonal flange (with pad) and so on.
Wrench mode - Wrench mode is varied. External wrench: hex, hex flange, hex flange, hex flower, etc.; Internal screw: Single slot, cross slot H type (Phillips), cross slot Z type (Pozidriv), cross slot F type (Frearson), square slot (Scrulox), composite slot, internal spline, hexagonal flower shape (club slot), internal triangle, hex, internal 12 Angle, clutch slot, six blade slot, high torque cross slot and so on.
Thread types - There are many kinds of threads. There are self-tapping thread (wide tooth thread), machine thread, drywall screw thread, fiberboard screw thread, and some other special thread. In addition, the thread can be divided into single lead (single head), double lead (double head), multiple lead (multiple) and high and low teeth double head thread. End type - The end type mainly has saw end and flat end. However, according to the function of use, grooves, notches or parts similar to drill bits with cutting functions can be machined. In some standards, the same saw end or flat end, there are also different forms. From the above introduction, it can be seen that there are various changes in the head shape of the tapping screw, the way of pulling and screwing, the type of thread and the end type of the rod. They can be combined with each other to release a large number of different products belonging to the category of self-tapping screws.
