Detailed Information On Bolt Specifications And Models

Both in production and use, there are strict regulations on the specifications and models of bolts. Therefore, for us consumers, understanding the specifications and models of bolts is very important for purchasing bolts. Now let me introduce detailed information about bolt specifications and models to you.

1】、 Bolt specifications and models - metric

1. Thread Code: Screw model

Metric screws are directly labeled with the outer diameter of the screw to indicate the screw model. For example, M3 means the outer diameter of the screw is 3.00mm, and M4 means the outer diameter of the screw is 4.00mm.

2. Metric Thread Size x Pitch: Metric screw model and pitch

Generally, the screw pitch is indicated after metric screws, such as M3x0.5, M4x0.70, M5x0.8, M6x1, and so on.

3. Length Code: Screw length

The length of metric screws directly indicates the length of the screw, in millimeters. The total length of the screw is only calculated below the head, excluding the head height. But the total length indication of flat head screws includes the head height.

4. Drive Code: Head groove, feature model

Commonly used head slits and feature models include: Minus, Plus, Straight/Cross, Hexagonal, Unidirectional (only lockable, not withdrawable), etc.

5. Head Code: Head Appearance

The commonly used head shapes include: flat head (after locking, the top is flush with the working part), salad head, round head, round flat head, large round flat head, hexagonal head, etc.

6. Finish Code: Appearance treatment specifications

Common appearance treatment specifications include: zinc plating, nickel plating, tin plating, zinc green film treatment, multicolor plating, antioxidant treatment, and no appearance treatment.

2】、 Bolt specifications and models - American standard

1. Thread Code: Screw model

American standard screws are generally labeled with serial numbers or imperial outer diameters, such as # 2-56, # 4-40, # 6-32, # 8-32, # 10-24, and so on.

2. Length Code: Screw length

The length of American standard screws needs to be converted to obtain the length of metric dimensions. The conversion formula is: (Length Code/32) x 25.40=metric length mm.

3. Head Code, Drive Code, and Finish Code: Head shape, head groove, feature model, and appearance treatment specifications

Similar to the metric system, there are corresponding regulations for the head shape, head groove, feature model, and appearance treatment specifications in the US regulations.

3】、 Bolt specifications and models - English system

The English pitch is expressed in terms of the number of teeth per inch. Usually it is at a 55 degree angle. In the metric system, the pitch is represented by the distance between the two teeth in millimeters, usually at a 60 degree angle. It is best to print the tip of the thread upside down on a white chalk pen for clearer measurement.

Summary:

Understanding the specifications and models of bolts is very important for purchasing bolts, as it can avoid purchasing incorrect sizes and specifications. The above introduction is the basic knowledge of bolt specifications and models, which requires us to further apply and learn in practical use and purchase.