Specifications Of Hexagon Socket Head Bolts And Specification Table

Hexagon socket head bolts are widely used fasteners. A good understanding of their specifications is essential for proper selection and purchase. Below is an introduction to the specifications of hexagon socket head bolts for your reference.

Technical Requirements for Metric Hexagon Socket Head Bolts

The specifications of hexagon socket head bolts shall meet the following technical requirements:

Slight rounding or counterboring at the opening of the hexagon socket is permitted.

The thread end shall be chamfered. Rolled ends are allowed for thread sizes d ≤ M4.

The length of incomplete thread U ≤ 2P, where P stands for thread pitch.

The top edge of the bolt head may be rounded or chamfered, at the manufacturer's discretion.

The bottom edge of the bolt head may be rounded or chamfered to dw dimension, and no burrs are allowed on the edge.

Commonly applicable national standards for hexagon socket fasteners include GB/T70.1 (Hexagon socket head cap screws), GB/T2672, GB/T2673, GB/T2674, GB/T6190 and GB/T6191.

Specifications of Imperial Hexagon Socket Head Bolts

Imperial bolts are measured in inches. Traditionally, one inch is divided into eight equal parts, and each part is called one fractional inch. For example, 1/8, 1/4 and 1/2 inches are commonly referred to as 1-point, 2-point and 4-point screws. Besides the 1/8-inch series, bolts based on 1/16-inch increments are also available on the market. For instance, 3/16 inch is known as one-and-a-half-point screw.

Imperial bolt specifications are sorted from small to large. Both metric and imperial bolts are identified mainly by outer thread diameter. Imperial bolts are additionally marked with threads per inch. Under the same conditions, the larger the bolt outer diameter, the fewer threads per inch. Imperial threads are classified into UNC coarse thread and UNF fine thread.

Both imperial and metric bolts are specified by thread diameter plus nominal length. One inch equals 25.4 millimeters. Imperial and metric threads differ in thread form and tolerance system. Conversions are for reference only; they are not interchangeable in actual assembly applications.

Summary

Familiarity with the specifications and specification table of hexagon socket head bolts is of great significance for identification and procurement. Mastering specification classification, technical requirements and the differences between metric and imperial systems enables correct selection and application of bolts to ensure reliable assembly performance.