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AN7-31
Aeronautical Standard Machine Bolt
Description
Airframe Bolt, Drilled
Specifications
| Country of Origin | USA |
|---|---|
| Distance From Head Largest Bearing Surface To Shank Hole Center | 3.046 inches nominal first hole |
| Drilling | Drilled Head |
| Fastener Length | 3.219 |
| Features Provided | Finished head |
| Grip | 2 9/16 in |
| Grip Length | 2 9/16, 2.562 |
| Hardness Rating | 26.0 rockwell c minimum and 32.0 rockwell c maximum |
| Head Height | 0.234 inches minimum and 0.266 inches maximum |
| Head Style | Hexagon Head |
| Head Type | Hexagon |
| Industry Standards/Certification | AN7 |
| Length | 3 7/32 in |
| Material | Steel |
| Material Specification | Mil-b-6812 mil spec all material responses |
| Min. Tensile Strength (psi) | 125000 pounds per square inch |
| NIIN | 00-156-2646 |
| NSN | 5306-00-156-2646 |
| Nominal Length | 3 7/32 |
| Shank Unthreaded Hole Diameter | 0.106 inches nominal first hole |
| Thread Class | 3a |
| Thread Diameter | 0.438 |
| Thread Length | 0.657 inches minimum |
| Thread Qty | 20 |
| Thread Qty Per Inch (tpi) | 20 |
| Thread Series Designator | UNF |
| Thread Size | 7/16-20 |
| Weight | 0.157 lb |
| Width Between Flats | 0.615 inches minimum and 0.627 inches maximum |
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.
- AN7-31A AN 7/16-20 · 0.099 in · Hexagon Head · Steel
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Catalog data updated 2026-07-05. Report a data error