Specifications And Specification Table Of Socket Head Cap Bolts

Socket head cap bolts are common fasteners in the mechanical field, and there are many considerations for their specification selection and purchase. The following are the specification requirements and relevant common sense of socket head cap bolts, providing reference for purchase and use.

I. Core Specification Requirements of Socket Head Cap Bolts

The specifications of socket head cap bolts must comply with clear standard requirements, mainly including the following aspects:

1. The socket hexagon mouth is allowed to be rounded or counterbored.

2. End chamfer: Socket head cap bolts with thread specification d≤M4 adopt rolled ends.

The length of incomplete thread U≤2P (P is the pitch) to ensure the effectiveness of thread connection.

4. The top edge of the bolt head can be designed as a rounded edge or a chamfer at the manufacturer's option.

5. The bottom edge of the bolt head can be designed as a rounded edge or chamfered to Dw (head diameter), but no burrs are allowed in either design to avoid affecting assembly.

6. Relevant national standards for socket head cap bolts: GB/T 2672 (Socket Head Cap Bolts, Half Thread), GB/T 2673 (Socket Head Cap Bolts, Full Thread), GB/T 2674 (Countersunk Head Socket Cap Bolts), GB/T 6190 (Socket Head Cap Bolts, Fine Thread) and GB/T 6191 (Countersunk Head Socket Cap Bolts, Fine Thread), etc. When purchasing, select according to actual needs with reference to the standards.

II. Imperial Specifications of Socket Head Cap Bolts

The specifications of socket head cap bolts can be divided according to the imperial system. The imperial system uses inches as the unit, with the basic division of 1 inch divided into 8 parts, each part called 1 "fen". For example, 1/8 inch is called 1-fen bolt, 1/4 inch is called 2-fen bolt, and 1/2 inch is called 4-fen bolt.

In addition to the basic division of 1/8 inch, bolts based on 1/16 inch can also be purchased in the spot market, for example, 3/16 inch is called half-fen bolt.

Imperial specifications are sorted from small to large in size. Like metric bolts, imperial bolts also take bolt diameter as the core measurement index, but add an additional "tooth count" (related to pitch) parameter - tooth count refers to the number of threads per inch of length. Usually, the larger the bolt diameter, the fewer the tooth count. In addition, the tooth count of imperial bolts is divided into coarse teeth and fine teeth, which should be selected according to force requirements and assembly scenarios.

Both imperial and metric bolts are expressed in "diameter + length", but they have different bases (1 inch ≈ 25.4 millimeters). They can be clearly distinguished in writing, but cannot be interchanged in practical application, otherwise it will lead to loose connection, inability to assemble and other problems.

III. Summary

A thorough understanding of the specification requirements of socket head cap bolts and the differences between imperial and metric systems is of great significance for understanding, purchasing and using socket head cap bolts. Only by proficiently mastering their specification standards and classification characteristics can we accurately purchase and standardize the use, give full play to the fastening effect of socket head cap bolts, and ensure the connection stability of equipment or structures.