The main purpose is to make the industrial products integrated and fixed. In use, it often happens that the teeth cannot be closely attached to the teeth, the screw heads are broken if the tightening is too strong, or the teeth are not tightly locked and cannot meet the conditions of use, all of which are accuracy problems. . Screws are "quantity products", not hand-made artworks. In mass production, they are supplied to consumers for the purpose of achieving high-precision, stable quality and popular prices. The accuracy of screws is usually 6g (level 2, American standard "IFI" is 2A thread), and the rough screw used in construction engineering is 8g (level 3, "IFI" is 1A thread).

A: Machine Screw: Machine Screw

B: Tapping Screw: Self-tapping screw (for metal and plastic)

B-1: Sheet Metal Tapping Screw. (Iron die tapping screw)

B-2: Plastic Tapping Screw. (For plastic, self-tapping screw)

C: Wooden Screw: Woodworking Screw

D: Drywall Screw: Cement wall screw

E: Self Drilling Screws (stainless steel self-drilling screws, composite material self-drilling screws)

F: Expansion screw, four-piece expansion screw is also known as: four-piece gecko.　The grades of expansion bolts are divided into: 45, 50, 60, 70, 80, 　The material of expansion screws: mainly divided into austenite A1, A2, A4,

1Stainless steel plate, metal steel plate, galvanized steel plate, engineering installation.

2 Indoor and outdoor installation of metal curtain wall, metal light partition, etc.

3 General angle steel, channel steel, iron plate and other metal materials are combined and installed.

4. Assembling projects for automobile trunks, container boxes, shipbuilding, refrigeration, screw machine equipment, etc.