bolts › close tolerance bolts
AN178-55
Aeronautical Standard Bolt
Description
Fastener Length: 5-3/4", Thread: 1/2-20, Thread Length: 53/64"
Specifications
| Distance From Head Largest Bearing Surface To Shank Hole Center | 5.547 inches nominal first hole |
|---|---|
| Fastener Length | 5.703 inches minimum and 5.750 inches maximum |
| Features Provided | Finished head |
| Grip Length | 4.922 inches minimum and 4.954 inches maximum |
| Hardness Rating | 26.0 rockwell c minimum and 32.0 rockwell c maximum |
| Head Height | 0.265 inches minimum and 0.297 inches maximum |
| Head Style | Hexagon Head |
| Length | 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 ams 6300 mil spec 6th material response |
| Min. Tensile Strength (psi) | 125000 pounds per square inch |
| Shank Unthreaded Hole Diameter | 0.106 inches nominal first hole |
| 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 | 0.500 |
| Thread Direction | Right-hand |
| Thread Length | 0.749 inches minimum and 0.828 inches maximum |
| Thread Qty | 20 |
| Thread Qty Per Inch (tpi) | 20 |
| Thread Series Designator | UNF |
| Thread Size | 1/2 |
| Width Between Flats | 0.740 inches minimum and 0.752 inches maximum |
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 AN178-55. Try the cross-reference lookup to search by a different part number.
Catalog data updated 2026-07-05. Report a data error