bolts › close tolerance bolts
NAS1581A4H6
Bolt
Description
Fastener Length: 25/32", Thread: 1/4-28, Thread Length: 27/64"
Specifications
| Countersink Angle | 99.0 degrees minimum and 101.0 degrees maximum |
|---|---|
| Fastener Length | 0.763 inches minimum and 0.793 inches maximum |
| Grip Diameter | 0.2485 inches minimum and 0.2495 inches maximum |
| Grip Length | 0.365 inches minimum and 0.385 inches maximum |
| Hardness Rating | 36.0 rockwell c minimum and 40.0 rockwell c maximum |
| Head Diameter | 0.350 inches minimum and 0.399 inches maximum |
| Head Style | Flat countersunk |
| Internal Drive Style | High-torque |
| Length | 25/32 |
| Material | Steel |
| Material Specification | Mil-s-5626 mil spec 1st material response or mil-s-5000 mil spec 2nd material response or mil-s-8503 mil spec 3rd material response or mil-s-6098 mil spec 4th material response or mil-s-6049 mil spec 5th material response |
| Min. Tensile Strength (psi) | 160000 pounds per square inch |
| Specification Data | 80205-nas1581 professional/industrial association standard |
| Surface Finish | 32.0 microinches grip, 32.0 microinches threads |
| Surface Treatment | Cadmium and chromate |
| Surface Treatment Specification | Qq-p-416,ty 2,cl 2 fed spec all treatment responses |
| Thread Class | 3a |
| Thread Diameter | 0.250 |
| Thread Direction | Right-hand |
| Thread Length | 0.378 inches minimum and 0.428 inches maximum |
| Thread Qty | 28 |
| Thread Qty Per Inch (tpi) | 28 |
| Thread Series Designator | UNJF |
| Thread Size | 1/4 |
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.
- NAS1581A4T6 NAS 1/4-28 · 25/32 in · Flat countersunk · Steel
- NAS1581F4H6 NAS 1/4-28 · 25/32 in · Flat countersunk · Steel
- NAS1581F4R6 NAS 1/4-28 · 25/32 in · Flat countersunk · Steel
- NAS1581K4T6 NAS 1/4-28 · 25/32 in · Flat countersunk · Titanium
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Catalog data updated 2026-07-05. Report a data error