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AN4-31
Aeronautical Standard Machine Bolt
Description
Airframe Bolt; Drilled
Specifications
| Country of Origin | USA |
|---|---|
| Drilling | Drilled Head |
| Features Provided | Finished head |
| Grip | 2 11/16 in |
| Grip Length | 2 11/16, Between 2.672 inches and 2.704 inches |
| Hardness Rating | 26.0 rockwell c and 32.0 rockwell c |
| Head Height | Between 0.140 inches and 0.172 inches |
| Head Style | Hexagon Head |
| Head Type | Hexagon |
| Industry Standards/Certification | AN4 |
| Length | 3 5/32 in, Between 3.142 inches and 3.187 inches |
| Material | Steel |
| Material Specification | Mil-s-5626 military specification 1st material response or mil-s-6049 military specification 2nd material response or mil-s-6050 military specification 3rd material response or mil-s-6098 military specification 4th material response or mil-s-6758 military specification 5th material response or ams 6300 assn standard 6th material response |
| Min. Tensile Strength (psi) | 125000 pounds per square inch |
| NIIN | 00-622-1823 |
| NSN | 5306-00-622-1823 |
| Nominal Length | 3 5/32 |
| Shank Unthreaded Hole Diameter | 0.076 inches first hole |
| Surface Treatment | Cadmium or chromate |
| Surface Treatment Specification | Qq-p-416 type 2 class 3 federal specification all treatment responses |
| Thread Class | 3a |
| Thread Diameter | 0.250 |
| Thread Direction | Right-hand |
| Thread Length | Between 0.438 inches and 0.515 inches |
| Thread Qty | 28 |
| Thread Qty Per Inch (tpi) | 28 |
| Thread Series | UNF |
| Thread Series Designator | Unf (fine thread) |
| Thread Size | 1/4-28 |
| Weight | 0.05 lb |
| Width Between Flats | Between 0.428 inches and 0.440 inches |
Cross-reference
No interchangeable or dimensionally similar parts are on record for AN4-31. Try the cross-reference lookup to search by a different part number.
Catalog data updated 2026-07-05. Report a data error