Product Description
5/16″-24 UNF Zinc Plated Part Thread Socket Cap Bolts – 12.9 Equivalent
Part threaded 5/16″ UNF socket cap bolts manufactured from high tensile alloy steel with a zinc plated finish. Each bolt has an unthreaded shank beneath the cylindrical cap head and an internal hexagon socket for installation using a 1/4″ Allen key.
These bolts feature a 5/16″-24 TPI Unified National Fine thread and are suitable for machinery, engineering assemblies, maintenance and repair work using matching UNF nuts or tapped holes.
Technical Specifications
| Nominal thread diameter | 5/16″ – 7.9375mm |
|---|---|
| Thread form | UNF – Unified National Fine |
| Threads per inch | 24 TPI |
| Approximate thread pitch | 1.058mm |
| Thread direction | Right hand |
| Thread coverage | Part threaded, with an unthreaded shank |
| Material | Heat-treated high tensile alloy steel |
| Imperial material specification | ASTM A574 |
| Metric strength comparison | Approximately equivalent to metric Class 12.9 |
| Finish | Zinc plated |
| Head style | Cylindrical socket cap head |
| Drive type | Internal hexagon socket |
| Allen key size | 1/4″ |
| Dimensional standard | ASME B18.3 |
| Length measurement | From beneath the head to the end of the bolt |
The Class 12.9 reference is an approximate metric strength comparison. These bolts retain their imperial UNF dimensions and ASTM A574 specification; the comparison does not indicate ISO Class 12.9 certification or interchangeability with metric threads.
Available Lengths
- 1 3/4″ – 44.45mm
- 2″ – 50.80mm
- 2 1/4″ – 57.15mm
- 2 1/2″ – 63.50mm
Metric measurements are provided for reference. Order using the imperial thread and length required.
These bolts are part threaded. Check the actual threaded and unthreaded lengths where these dimensions are critical to the assembly.
Key Features
- High tensile alloy steel with an approximate metric Class 12.9 strength equivalent.
- Part threaded construction with a plain shank beneath the head.
- Zinc plated finish for corrosion protection.
- Internal hexagon drive using a 1/4″ Allen key.
- 5/16″-24 TPI UNF fine thread.
Selection and Installation
Check that the mating thread is 5/16″-24 UNF and that the shank and threaded lengths suit the assembly. Ensure adequate thread engagement without bottoming out in a blind hole. Use a correctly fitting 1/4″ Allen key, fully seated in the socket.
Pack Quantities
Available in quantities of 1, 5, 10, 20, 50 and 100. Select the required length and quantity from the options.
Standards and References
- ASME B18.3 – imperial socket cap screw dimensions.
- ASTM A574 – alloy steel socket head cap screw requirements.
- ASME B1.1 – Unified inch screw threads.
