About Allen Bolts
Allen bolts are precision fasteners designed with an internal hex drive built directly into the bolt head, allowing tightening without the need for external gripping surfaces. This internal drive design makes them especially effective in compact or restricted installation areas where traditional bolts are difficult to access.
Allen head bolts are installed using hex or Allen keys, which deliver consistent torque while reducing the risk of slippage during assembly. Depending on application requirements, Allen bolts are available in multiple head configurations including socket head, flat head, and button head, offering flexibility for both structural strength and surface appearance.
These fasteners are often supplied by the name hex socket bolt or allen head bolts and are made of a very large variety of metals. Allen bolts are manufactured in both metric and imperial sizes and are easily compatible with the thread systems typically used including UNC, UNF, UN, and the ISO metric allowing their application in engineering and industrial applications globally.
Allen Bolts Properties
| Property | Details |
|---|---|
| Manufacturing | Hot Forged / Cold Forged |
| Metric Size | M3 to M72 |
| Imperial Size | 1/4” to 3” |
| Threads | Metric, UNC, UNF, BSW |
| Form | Fully Threaded / Partially Threaded |
| Standards | ASTM, ASME, DIN, ISO, BS, IS |
| Sub Types | As per product category |
Allen Bolts Standards
| Standard | Size Range |
|---|---|
| ASME B18.2.1 / B18.2.2 | 1/4” to 3” |
| ASTM A194 / A193 | M6 to M72 |
| DIN 934 / DIN 6914 | M6 to M72 |
| ISO 4032 / ISO 7412 | M6 to M72 |
| BS 1769 | 1/4” to 2” |
| IS 1363 | M6 to M72 |
Allen Bolts Specifications
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