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AN4H21A
Aeronautical Standard Machine Bolt
Description
Airframe Bolt; Drilled Head
Specifications
| Country of Origin | USA |
|---|---|
| Fastener Length | 2.156 |
| Features Provided | Finished head |
| Grip Length | 1.688 |
| 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 |
| Hole Configuration Style | Hexagon flats |
| Hole Diameter | 0.046 |
| Hole Quantity | 1 |
| Hole Type | Drilled |
| Length | 2 1/8 |
| Material | Steel |
| Material Specification | Mil-b-6812 mil spec all material responses |
| Min. Tensile Strength (psi) | 125000 pounds per square inch |
| NIIN | 00-180-3360 |
| NSN | 5306-00-180-3360 |
| 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 | 0.468 inches minimum |
| Thread Qty | 28 |
| Thread Qty Per Inch (tpi) | 28 |
| Thread Series Designator | UNF |
| Thread Size | 1/4 |
| Weight | 0.04 lb |
| Width Between Flats | 0.428 inches minimum and 0.440 inches maximum |
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Catalog data updated 2026-07-05. Report a data error