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AN4C4
Aeronautical Standard Machine Bolt
Description
Airframe Bolt; Drilled
Specifications
| Country of Origin | USA |
|---|---|
| Distance From Head Largest Bearing Surface To Shank Hole Center | 0.359 inches first hole and 0.391 inches first hole |
| Fastener Length | Between 0.516 inches and 0.562 inches |
| Features Provided | Finished head |
| Grip Length | Between 0.047 inches and 0.078 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 |
| Material | Steel |
| Material Specification | Mil-s-18732 military specification single material response |
| Min. Tensile Strength (psi) | 125000 pounds per square inch |
| NIIN | 00-151-2550 |
| NSN | 5306-00-151-2550 |
| Shank Unthreaded Hole Diameter | 0.076 inches first hole and 0.086 inches first hole |
| Surface Treatment | Passivate |
| Thread Class | 3a |
| Thread Diameter | 0.250 |
| Thread Direction | Right-hand |
| Thread Length | Between 0.438 inches and 0.516 inches |
| Thread Qty | 28 |
| Thread Qty Per Inch (tpi) | 28 |
| Thread Series | UNF |
| Thread Series Designator | Unf (fine thread) |
| Thread Size | 1/4 |
| Weight | 0.01 lb |
| Width Between Flats | Between 0.428 inches and 0.440 inches |
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.
- AN4C4A AN 1/4-28 · 9/16 in · Hexagon Head · Steel
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Catalog data updated 2026-07-05. Report a data error