bolts › machine bolts
MS21280-14
Military Standard Machine Bolt
Description
Fastener Length: 1", Thread: 1/4-28, Thread Length: 3/4"
Specifications
| Extended Washer Diameter | 0.428 inches minimum and 0.448 inches maximum |
|---|---|
| Extended Washer Thickness | 0.060 inches minimum and 0.070 inches maximum |
| Fastener Length | 0.990 inches minimum and 1.010 inches maximum |
| Features Provided | Finished head |
| Head Height | 0.320 inches minimum and 0.340 inches maximum |
| Head Style | Double hexagon w/hole |
| Length | 0 63/64 |
| Material | Iron |
| Material Specification | Ams 5732 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, 63.0 microinches grip |
| Thread Class | 3a |
| Thread Diameter | 0.250 |
| Thread Direction | Right-hand |
| Thread Length | 0.740 inches minimum and 0.820 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
Similar parts
Parts with matching key dimensions — often from a different standards family. Candidates for comparison only; verify the full specification before substituting.
- AS9557-14 AS 1/4-28 · 1/16 in · Double hexagon w/hole · Iron
Looking for a specific part? Use the cross-reference lookup.
Catalog data updated 2026-07-05. Report a data error