Product Description
5/16"-18 UNC A2 Stainless Steel Countersunk Socket Set Screws
These 5/16"-18 UNC countersunk socket set screws feature a flat countersunk head with an internal hexagon drive. When installed into a correctly prepared countersink, the head can sit flush with the surrounding surface for a neat, obstruction-free finish.
Manufactured from A2 stainless steel, these screws offer good general-purpose corrosion resistance for engineering, fabrication, machinery, automotive and maintenance applications. The coarse 5/16" UNC thread has 18 threads per inch.
Product specifications
- Thread size: 5/16"-18 UNC
- Thread series: Unified National Coarse
- Threads per inch: 18 TPI
- Material: A2 stainless steel
- Head style: Flat countersunk socket head
- Countersink pattern: 82-degree inch-series pattern
- Drive type: Internal hexagon or Allen drive
- Available lengths: 3/4", 1", 1 1/4" and 1 1/2"
- Available pack sizes: 1–10, 20, 50, 100, 250, 500 and 1,000
Available lengths
| Thread size | Length | Threads per inch |
|---|---|---|
| 5/16" UNC | 3/4" | 18 TPI |
| 5/16" UNC | 1" | 18 TPI |
| 5/16" UNC | 1 1/4" | 18 TPI |
| 5/16" UNC | 1 1/2" | 18 TPI |
Length measurement: Countersunk screw lengths are conventionally measured overall, including the head. Check the required overall length and countersink depth before ordering.
Selection and installation
- Confirm that the mating component has a 5/16"-18 UNC thread.
- Do not confuse this coarse 18 TPI thread with 5/16"-24 UNF.
- Use the correct imperial hex key and ensure it is fully inserted before tightening.
- Prepare the mating component with the appropriate 82-degree countersink where a flush finish is required.
- Consider a suitable anti-galling lubricant when assembling stainless-steel threaded components.
- Countersunk heads generally have a lower load capacity than equivalent socket-cap heads, so follow the application’s specified tightening requirements.
Related categories and technical information
- Browse UNC countersunk socket screws
- Browse all countersunk socket screws
- View the Metric, UNC, UNF and BSP thread data guide
- How to measure a bolt or screw
- Stainless-steel thread galling and prevention guide
- A2 versus A4 stainless-steel guide
Specifications are provided as a guide. If a dimension, material property or formal standards compliance is critical to your application, please contact us for confirmation before ordering.
