bolts › close tolerance bolts
AN178H27
Aeronautical Standard Close Tolerance Bolt
Description
Fastener Length: 2-63/64", Hole Diameter: 1/16", Thread: 1/2-20, Thread Length: 53/64
Specifications
| Distance From Head Largest Bearing Surface To Shank Hole Center | 2.781 inches minimum first hole and 2.813 inches maximum first hole |
|---|---|
| Fastener Length | 2.953 inches minimum and 3.000 inches maximum |
| Grip Diameter | 0.4986 inches minimum and 0.4991 inches maximum |
| Grip Length | 2.172 inches minimum and 2.204 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 |
| Hole Configuration Style | Hexagon flats |
| Hole Diameter | 0.070 |
| Hole Quantity | 1 |
| Hole Type | Drilled |
| Length | 2 63/64 |
| Material | Steel |
| Material Specification | Mil-s-6049 mil spec 1st material response or mil-s-6050 mil spec 2nd material response or mil-s-6098 mil spec 3rd material response or ams 6300 assn std 4th material response or mil-s-5626 mil spec 5th material response or mil-s-6758 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 Finish | 63.0 microinches bearing surface of head, 63.0 microinches grip |
| Surface Treatment | Cadmium and chromate |
| Surface Treatment Specification | Qq-p-416,ty2 cl3 fed spec single treatment response |
| 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.
- AN178H24
- AN178H27
Cross-reference
No interchangeable or dimensionally similar parts are on record for AN178H27. Try the cross-reference lookup to search by a different part number.
Catalog data updated 2026-07-05. Report a data error