Self-tapping screw construction. Each self-tapping screw is composed of three parts: the head, the rod and the end of the rod. Each self tapping screw is composed of four elements: head appearance, pulling method, thread type, tail way.
1. Head appearance
The heads come in all shapes and sizes. There are round mouth (half round head), flat circular head, round mouth flange (with pad), flat circular head flange (with pad), pan head, pan head flange (with pad), countersunk head, half countersunk head, cylindrical head, spherical cylindrical top, horn head, hexagonal head, hexagonal flange head, hexagonal flange (with pad).
2. Pulling and twisting method
Screw way refers to the installation and fastening screws when the screw head distortion form, basically there are external screw and internal screw two ways. Generally speaking, the external wrench allows greater torque than any form of internal wrench (concave groove). External wrench: hexagonal, hexagonal flange surface, hexagonal flange, hexagonal flower shape, etc. Internal screw: one groove, cross groove H type, cross groove Z type, cross groove F type, square groove, compound groove, inner spline, inner hexagon pattern, inner triangle, inner hexagon, inner 12 Angle, clutch groove, six leaf groove, high torque cross groove, etc.
3. Screw thread type
There are many kinds of thread, tapping thread (wide tooth thread), machine thread (general thread), drywall screw thread, fiberboard screw thread, and some other special thread. In addition, the thread can be divided into single pitch (double head), double pitch (multi-head), multi-pitch (double-head) and how many teeth multi-head thread.
4, end way
The tail end mode mainly includes two kinds: cone end and friendship end. However, according to the requirements of the application, the tightening part at the tail end can produce and process the functional groove, groove, wound or a part similar to the shape of twist drill, etc. In some standards, the same cone end or flat end, there are different ways such as round mouth end.
Post time: Mar-09-2023