Product Description
5/16"-18 UNC high tensile Grade 5 zinc plated steel hexagon head bolts, available in imperial lengths from 1 1/4" to 6".
These imperial hex head bolts feature a coarse 18 threads per inch UNC thread and a partially threaded shank. The unthreaded section provides a solid bearing surface through the components being fastened, making them suitable for machinery, automotive, agricultural, engineering, fabrication, restoration and general maintenance applications.
- Thread size: 5/16" UNC
- Thread pitch: 18 threads per inch
- Thread form: Unified National Coarse
- Material: High tensile steel
- Strength grade: SAE Grade 5
- Approximate metric strength equivalent: Property Class 8.8
- Finish: Bright zinc plated
- Head style: Hexagon head
- Fastener type: Partially threaded bolt with shank
- Approximate spanner size: 1/2" AF
- Approximate head height: 7/32"
- Available lengths: 1 1/4", 1 1/2", 1 3/4", 2", 2 1/4", 2 1/2", 2 3/4", 3", 3 1/4", 3 1/2", 3 3/4", 4", 4 1/2", 5" and 6"
- Length measured from beneath the bolt head to the end of the thread
- Pack sizes available: 1, 5, 10, 20, 50 and 100
UNC threads have a relatively coarse pitch, making them suitable for general-purpose fastening, frequent assembly and applications where good resistance to thread damage is required.
These bolts are designed for use with compatible 5/16"-18 UNC nuts, tapped holes and washers. The plain shank should pass through the components being clamped, with the threaded section positioned beyond the joint wherever possible.
SAE Grade 5 is an imperial high-tensile fastener grade commonly compared with metric Property Class 8.8. The two grading systems are not identical, so the correct specified grade should always be used for safety-critical or regulated applications.
Bright zinc plating provides general corrosion resistance for indoor and sheltered environments. For prolonged outdoor, marine, coastal or highly corrosive conditions, stainless steel or a more protective specialist coating may be more suitable.
Hexagon bolt length is measured from beneath the head to the end of the bolt.
Please note: Dimensions and thread lengths may vary slightly by manufacturer and production batch. Specifications are intended as a guide only. If dimensions, grade compliance or thread length are critical to your project, please check with us before ordering.
| A | B | C | D | E | F | G |
| 5/16" | 1 1/2" | 7/8" | 1/2" | 7/32" | 18 | 5/8" |
| 5/16" | 1 1/4" | 7/8" | 1/2" | 7/32" | 18 | 3/8" |
| 5/16" | 2" | 7/8" | 1/2" | 7/32" | 18 | 1 1/8" |
| 5/16" | 3 1/2" | 7/8" | 1/2" | 7/32" | 18 | 2 5/8" |
| 5/16" | 4" | 7/8" | 1/2" | 7/32" | 18 | 3 1/8" |
| 5/16" | 2 1/4" | 7/8" | 1/2" | 7/32" | 18 | 1 3/8" |
| 5/16" | 3" | 7/8" | 1/2" | 7/32" | 18 | 2 1/8" |
| 5/16" | 2 1/2" | 7/8" | 1/2" | 13/64 | 18 | 1 5/8" |
| 5/16" | 2 3/4" | 7/8" | 1/2" | 13/64 | 18 | 1 7/8" |
| 5/16" | 3 3/4" | 7/8" | 1/2" | 13/64 | 18 | 2 7/8" |
| 5/16" | 3 1/4" | 7/8" | 1/2" | 13/64 | 18 | 2 7/8" |
| 5/16" | 5" | 1" | 1/2" | 7/32" | 18 | 4" |
| 5/16" | 4 1/2" | 1" | 1/2" | 13/64 | 18 | 3 1/2" |
Please Note: Specifications given are intended as a guide only. If critical to your project please check with us first.
