Product Description
1/2″-20 UNF Zinc Plated Socket Cap Screws – Fully Threaded, 12.9 Equivalent
Fully threaded 1/2″ UNF socket cap screws manufactured from high tensile alloy steel with a zinc plated finish. The cylindrical cap head features an internal hexagon socket for installation using a 3/8″ Allen key.
These screws have a 1/2″-20 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 | 1/2″ – 12.70mm |
|---|---|
| Thread form | UNF – Unified National Fine |
| Threads per inch | 20 TPI |
| Thread pitch | 1.27mm |
| Thread direction | Right hand |
| Thread coverage | Fully threaded |
| 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 | 3/8″ |
| Dimensional standard | ASME B18.3 |
| Length measurement | From beneath the head to the end of the screw |
The Class 12.9 reference is an approximate metric strength comparison. These screws 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″ – 25.40mm
- 1 1/4″ – 31.75mm
- 1 1/2″ – 38.10mm
- 1 3/4″ – 44.45mm
- 2″ – 50.80mm
Metric measurements are provided for reference. Order using the imperial thread and length required.
Key Features
- High tensile alloy steel with an approximate metric Class 12.9 strength equivalent.
- Fully threaded for use with matching nuts and tapped holes.
- Zinc plated finish for corrosion protection.
- Internal hexagon drive using a 3/8″ Allen key.
- 1/2″-20 TPI UNF fine thread.
Selection and Installation
Check that the mating thread is 1/2″-20 UNF and select a length that provides suitable thread engagement without bottoming out in a blind hole. Use a correctly fitting 3/8″ 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.
