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AN175-31A
Aeronautical Standard Close Tolerance Bolt
Description
Close Tolerance Bolt
Specifications
| Country of Origin | USA |
|---|---|
| Drilling | Undrilled Head |
| Fastener Length | 3.219 |
| Grip | 2 11/16 in |
| Grip Diameter | Between 0.3112 inches and 0.3117 inches |
| Grip Length | 2.688 |
| Head Height | Between 0.172 inches and 0.204 inches |
| Head Style | Hexagon Head |
| Head Type | Hexagon |
| Industry Standards/Certification | AN175 |
| Length | 3 7/32 in |
| Material | Steel |
| Min. Tensile Strength (psi) | 125000 pounds per square inch |
| NIIN | 00-550-3319 |
| NSN | 5306-00-550-3319 |
| Surface Finish | 63.0 microinches grip, 63.0 microinches surface of head |
| Surface Treatment | Cadmium and chromate |
| Surface Treatment Specification | Qq-p-416 type 2 cl 3 federal specification single treatment response |
| Thread Class | 3a |
| Thread Diameter | 0.312 |
| Thread Direction | Right-hand |
| Thread Length | 0.531 |
| Thread Qty | 24 |
| Thread Qty Per Inch (tpi) | 24 |
| Thread Series Designator | Unf (fine thread) |
| Thread Size | 0.3125-24, 1/4 |
| Weight | .005 lb |
| Width Between Flats | Between 0.490 inches and 0.502 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.
- AN175-31 AN 24.00-24 · 0.099 in · Hexagon Head · Steel
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Catalog data updated 2026-07-05. Report a data error