bolts › close tolerance bolts
AN178-26
Aeronautical Standard Close Tolerance Bolt
Description
Close Tolerance Bolt
Specifications
| Country of Origin | USA |
|---|---|
| Fastener Length | 2.844 |
| Grip | 2 1/16 in |
| Grip Diameter | Between 0.4986 inches and 0.4991 inches |
| Grip Length | 2.062 |
| Hardness Rating | 26.0 rockwell c and 32.0 rockwell c |
| Head Height | Between 0.265 inches and 0.297 inches |
| Head Style | Hexagon Head |
| Head Type | Hexagon |
| Industry Standards/Certification | AN178 |
| Length | 2 13/16 in |
| Material | Steel |
| Material Specification | Mil-s-6049 military specification 1st material response or mil-s-6050 military specification 2nd material response or mil-s-6098 military specification 3rd material response or mil-s-5626 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 | 00-180-0328 |
| NSN | 5306-00-180-0328 |
| Shank Unthreaded Hole Diameter | 0.106 inches first hole |
| Surface Finish | 63.0 microinches grip, 63.0 microinches surface of head |
| Surface Treatment | Cadmium and chromate |
| Surface Treatment Specification | Class 3 federal specification all treatment responses type 2 qq-p-416 |
| Thread Class | 3a |
| Thread Diameter | 0.500 |
| Thread Direction | Right-hand |
| Thread Length | 0.782 |
| Thread Qty | 20 |
| Thread Qty Per Inch (tpi) | 20 |
| Thread Series | UNF |
| Thread Series Designator | Unf (fine thread) |
| Thread Size | 1/2 |
| Weight | 0.19 lb |
| Width Between Flats | Between 0.740 inches and 0.752 inches |
Other sizes
Parts that share this base number, ordered by size. Always verify the full specification before substituting.
Cross-reference
No interchangeable or dimensionally similar parts are on record for AN178-26. Try the cross-reference lookup to search by a different part number.
Catalog data updated 2026-07-05. Report a data error