bolts › machine bolts
MS21280-08
Military Standard Bolt
Description
Fastener Length: 5/8", Thread: 1/4-28, Thread Length: 35/64"
Specifications
| Extended Washer Diameter | 0.438 |
|---|---|
| Extended Washer Thickness | 0.060 inches minimum and 0.070 inches maximum |
| Fastener Length | 0.615 inches minimum and 0.635 inches maximum |
| Features Provided | Finished head |
| Hardness Rating | 248.0 brinell standard minimum and 341.0 brinell standard maximum |
| Head Height | 0.320 inches minimum and 0.340 inches maximum |
| Head Style | Double hexagon w/hole |
| Length | 5/8 |
| Material | Iron |
| Material Specification | Ams 5735 assn std single material response |
| Min. Tensile Strength (psi) | 130000 pounds per square inch |
| Minimum Yield Strength | 85000 pounds per square inch |
| Surface Finish | 32.0 microinches threads, 63.0 microinches bearing surface of head |
| Thread Class | 3a |
| Thread Diameter | 0.250 |
| Thread Direction | Right-hand |
| Thread Length | 0.544 inches minimum and 0.635 inches maximum |
| Thread Qty | 28 |
| Thread Qty Per Inch (tpi) | 28 |
| Thread Series Designator | UNJF |
| Thread Size | 1/4 |
| Width Between Flats | 0.304 inches minimum and 0.313 inches maximum |
Other sizes
Parts that share this base number, ordered by size. Always verify the full specification before substituting.
Cross-reference
No interchangeable or dimensionally similar parts are on record for MS21280-08. Try the cross-reference lookup to search by a different part number.
Catalog data updated 2026-07-05. Report a data error