What are all the construction types of self-tapping screws?

Every self-tapping screw is made up of three parts: the head, the shank, and the end of the shank. Each self-tapping screws are composed of four major elements: head shape, screwing method, thread type, end form.

1, head shape

Head shape is various. There are round head (semi-circular head), flat round head, round head flange (with gasket), flat round head flange (with gasket), disk head, disk head flange (with gasket), countersunk head, semi-countersunk head, cylindrical head, spherical cylindrical head, flared head, hexagonal head, hexagonal flange head, hexagonal flange (with gasket) head and so on.

2, the wrenching method

The wrenching method refers to the installation and fastening of screws when the screw head of the way to twist, the basic way of external wrenching and internal wrenching of two kinds. Generally speaking, the external wrenching than any form of internal wrenching (internal groove) allows a little more torque. External wrenching: hexagonal, hexagonal flange face, hexagonal flange, hexagonal pattern, etc.; internal wrenching: a groove, cross groove H-type, cross groove Z-type, cross groove F-type, quadrilateral groove, composite groove, internal spline, internal hexagonal pattern, internal triangular, internal hexagonal, internal 12-angle, clutch groove, six-blade type groove, high-torque cross groove.

3, thread types

Thread types are numerous, there are self-tapping threads (wide threads), machine threads (ordinary threads), drywall nails threads, fiberboard nails threads, as well as some other special threads. In addition, the thread can be divided into single lead (single head), double lead (double head), multi-lead (multi-head) and high and low teeth double head thread.

4, the end of the form

The end of the form of the main tapered end and flat end two. However, according to the use of needs, in the end of the screwed part, can be processed with cutting function of the groove, groove, notch or similar to the shape of the part of the drill, etc.. In some standards, the same tapered end or flat end, there are different forms such as round end.

Based on the development and evolution of self-tapping screws, we believe that the main types of self-tapping screws are as follows:

1, ordinary self-tapping screws

Thread "self-tapping thread", also known as "wide thread". The surface is mostly plated.

2, self-cutting self-tapping screws

China's standard called "self-tapping screws scraping end", the thread is self-tapping thread or machine thread, cross groove is also "H" type. Self-cutting tapping screws have the following types: cross recessed pan head self-cutting tapping screws, cross recessed countersunk head self-cutting tapping screws. Cross recessed semi-countersunk head self-cutting tapping screws, hexagonal head self-cutting tapping screws.

3, self-extruding tapping screws (self-tapping locking screws)

Self-extruding tapping screws are generally machine threads, rarely use self-tapping threads. In the wrenching method, in order to ensure the use of high-speed automatic assembly wrench, generally not recommended to use slotted. Self-extruding self-tapping screws have a three-pronged screw cross-section. So it is also called triangular threaded screws.

4, self-drilling self-tapping screws (self-drilling screws)

Self-drilling self-tapping screws thread, China, Germany and international standards for self-tapping thread. U.S. ASME and SAE standards in the BSD type self-drilling self-tapping screws for self-tapping threads, CSD type self-drilling self-tapping screws for machine threads. Self-drilling tapping screws are not recommended to use "slotted" and "common hex head".

5, metal drive screws (metal tapping screws)

Metal drive screws for the thread for the multi-head, and with a certain spiral angle of the special thread. Only the U.S. standard metal drive screws, our country and the German standard is not.

6, wallboard tapping screws (drywall nails)

Wallboard white tapping screws for the flare head, cross groove (H-type), 60 ° tooth angle of the special thread, the surface of the surface is mostly phosphate treatment (phosphating).

7, fiberboard nails

Cross slot for the Z-type, the surface treatment is mostly plating. Fiberboard nails have the following types of several types: countersunk head, double countersunk head fiberboard nails, pan head, pan head flange (with pad) fiberboard nails, half countersunk head, half countersunk head flange (with pad) fiberboard nails.

8, a combination of self-tapping screws

Ordinary white tapping screws, self-cutting white tapping screws, self drilling self-tapping screws and flat washers, elastic washers (including spring washers, elastic lock washers shaped t into a combination of self-tapping screws.

9, other types of self-tapping screws

High, low teeth double lead self-tapping screws, coarse and fine teeth (different pitch) thread self-tapping screws, thread coated with sealing material (drop-resistant) tapping screws, a variety of composite groove self-tapping screws, other special design juice self-tapping screws.

In short, there are many types of self-tapping screws, with the development of production, technological advances, new materials, new structures, new forms of thread, new self-tapping screws products will continue to appear.