bolts › close tolerance bolts
NAS1581F4T4X
Bolt
Description
Fastener Length: 21/32", Thread: 1/4-28, Thread Length: 3/8"
Specifications
| Countersink Angle | 99.0 degrees minimum and 101.0 degrees maximum |
|---|---|
| Fastener Length | 0.638 inches minimum and 0.668 inches maximum |
| Head Diameter | 0.3504 inches minimum and 0.3998 inches maximum |
| Head Style | Flat countersunk |
| Internal Drive Style | Offset cruciform (torque set) |
| Length | 21/32 |
| Material | Steel |
| Material Specification | Mil-s-5626 mil spec 1st material response or mil-s-5000 mil spec 2nd material response or mil-s-6049 mil spec 3rd material response |
| Shoulder Diameter | 0.2641 inches minimum first shoulder and 0.2651 inches maximum first shoulder |
| Shoulder Length | 0.240 inches minimum first shoulder and 0.260 inches maximum first shoulder |
| Shoulder Shape | Round first shoulder |
| Specification Data | 80205-nas1581 professional/industrial association standard |
| Surface Treatment | Cadmium and chromate |
| Surface Treatment Specification | Qq-p-416 ty 2 cl2 fed spec single treatment response |
| Thread Class | 3a |
| Thread Diameter | 0.250 |
| Thread Direction | Right-hand |
| Thread Length | 0.403 |
| Thread Qty | 28 |
| Thread Qty Per Inch (tpi) | 28 |
| Thread Series Designator | UNJF |
| Thread Size | 1/4 |
Other sizes
Parts that share this base number, ordered by size. Always verify the full specification before substituting.
Cross-reference
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Catalog data updated 2026-07-05. Report a data error