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AN4-56A
Aeronautical Standard Airframe Bolt
Description
Airframe Bolt
Specifications
| Country of Origin | USA |
|---|---|
| Drilling | Undrilled Head |
| Fastener Length | 5.781 |
| Features Provided | Finished head |
| Grip | 5 5/16 in |
| Grip Length | 5 5/16, 5.312 |
| Hardness Rating | 26.0 rockwell c minimum and 32.0 rockwell c maximum |
| Head Height | 0.140 inches minimum and 0.172 inches maximum |
| Head Style | Hexagon Head |
| Head Type | Hexagon |
| Industry Standards/Certification | AN4 |
| Length | 5 25/32 in, 5 3/4 |
| Material | Steel |
| Material Specification | Mil-s-5626 mil spec 1st material response or mil-s-6049 mil spec 2nd material response or mil-s-6050 mil spec 3rd material response or mil-s-6098 mil spec 4th material response or mil-s-6758 mil spec 5th material response or mil-s-8695 mil spec 6th material response |
| Min. Tensile Strength (psi) | 125000 pounds per square inch |
| NIIN | 00-151-1094 |
| NSN | 5306-00-151-1094 |
| Nominal Length | 5 25/32 |
| Surface Treatment | Cadmium and chromate |
| Surface Treatment Specification | Qq-p-416 ty 2 cl 3 fed spec all treatment responses |
| Thread Class | 3a |
| Thread Diameter | 0.250 |
| Thread Direction | Right-hand |
| Thread Length | 0.469 inches minimum |
| Thread Qty | 28 |
| Thread Qty Per Inch (tpi) | 28 |
| Thread Series Designator | UNF |
| Thread Size | 1/4-28 |
| Weight | 0.09 lb |
| Width Between Flats | 0.428 inches minimum and 0.440 inches maximum |
Cross-reference
No interchangeable or dimensionally similar parts are on record for AN4-56A. Try the cross-reference lookup to search by a different part number.
Catalog data updated 2026-07-05. Report a data error