Specifications and Types of Screws

January 9, 2023
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Screw, also called "screw" [Screw] (screw nail), "screw" (screw rod). In fact, screw is the common name, and screw, screw rod are different from each other. Screw is generally called wood screws; is the front end of a pointed kind, the pitch is larger, generally used to fasten wooden parts, plastic parts. Screw rod is machine screws (mechanical screws), is the front end of the kind of flat head, pitch is small, uniform, generally used to fasten metal, machine parts.

Common specifications

A: Metric screws B: American screws C: Inch screws
A: Metric machine screws: Metric
Ex: M3 x 6 - P P B : M3 machine screw, 6mm long, Phillips, round flat head, black plated.
Finish Code: Appearance specification
Head Code: Head profile.
Screw head profile. Cylindrical head. Semi-countersunk head. Countersunk head. Spherical cylindrical head. Pan head. Semi-round head. Hexagonal head.

Common types of screws
A: Machine Screw
B: Tapping Screw
B-1: Sheet Metal Tapping Screw
B-2: Plastic Tapping Screw
C: Wooden Screw
D: Drywall Screw
E: Self Drilling Screws
F: Expansion Screws, Four Piece Expansion Screws aka: Four Piece Gecko. The grade of expansion screws are divided into: 45, 50, 60, 70, 80, the material of expansion screws: mainly divided into austenitic A1, A2, A4
1 stainless steel plate, metal steel plate, galvanized steel plate, engineering installation.
2 metal curtain wall metal light compartment and other indoor and outdoor installation.
3 general angle steel, channel steel, iron plate and other metal materials combined with the installation.
4 car trunk, container box, shipbuilding industry, refrigeration, screw machine equipment and other assembly projects.