According to the development and evolution of self-tapp […]
According to the development and evolution of self-tapping screws, we believe that the types of self-tapping screws are mainly the following:
1, ordinary self-tapping screws
The thread is a "self-tapping thread", also known as a "wide thread." The surface is mostly electroplated.
2, self-cutting self-tapping screws
China's standard is called "self-tapping screw scraping end", the thread is self-tapping thread or machine thread, and the cross slot is also "H" type. Self-cutting self-tapping screws are available in the following types: self-cutting self-tapping screws for cross recessed pan heads, and self-cutting self-tapping screws for cross recessed countersunk heads. Self-cutting self-tapping screws for self-cutting cross-slot heads, self-cutting self-tapping screws.
3, self-squeezing self-tapping screws (self-tapping screws)
The threads of self-squeezing self-tapping screws are generally machine threads, and self-tapping threads are rarely used. In the wrenching mode, slotting is generally not recommended to ensure the use of high-speed automatic assembly wrenches. The screw cross section of the self-squeezing self-tapping screw is triangular. So it is also called a triangular threaded screw.
4, self-drilling self-tapping screws (self-drilling screws)
The threads of self-drilling self-tapping screws are self-tapping threads in China, Germany and international standards. In the American ASME and SAE standards, the BSD self-drilling self-tapping screws are self-tapping screws, and the CSD self-drilling self-tapping screws are machine threads. Self-drilling self-tapping screws are not recommended for "grooving" and "normal hex heads".
5, metal drive screw (metal tapping screw)
The metal drive screw has a multi-threaded thread and a special thread with a certain helix angle. Only metal drive screws are available in the US standard, not in China and Germany.
6, wall panel self-tapping screws (drywall nails)
The wall panel white tapping screw is a horn head, a cross groove (H type), a special thread of a 60° tooth angle, and the surface is mostly phosphate treated (phosphating).
7, fiberboard nails
The cross recess is Z-shaped, and the surface treatment is mostly electroplating. The fiberboard nails are available in several types: countersunk heads, double countersunk fiberboard nails, pan heads, pan head flanges (with pad) fiberboard nails, semi-sunk heads, and semi-sunk head flanges (with pad) fiberboard nails.
8, combined self-tapping screws
Ordinary white tapping screws, self-cutting white tapping screws, self-drilling self-tapping screws, etc., combined with flat washers, elastic washers (including spring washers, elastic lock washers).
9. Other self-tapping screw types
High and low tooth double lead self-tapping screws, self-tapping screws for coarse and fine teeth (different pitch), self-tapping screws with sealing material (falling resistance), self-tapping screws for various composite grooves, other special juices Self-tapping screws, etc.
In short, there are many types of self-tapping screws. With the development of production, advances in technology, new materials, new structures, and new thread forms, new self-tapping screws will continue to appear.