screws › close tolerance screws
NAS1581F4T12
Close Tolerance Screw
Description
Flush Reduced Head Bolt
Specifications
| Countersink Angle | 99.0 degrees maximum and 101.0 degrees maximum |
|---|---|
| Country of Origin | USA |
| Fastener Length | 1.138 inches minimum and 1.168 inches maximum |
| Grip Diameter | 0.2485 inches minimum and 0.2495 inches maximum |
| Grip Length | 0.740 inches minimum and 0.760 inches maximum |
| Head Diameter | 0.3504 inches minimum and 0.3988 inches maximum |
| Head Style | Flat countersunk |
| Internal Drive Style | Offset cruciform (torque set) |
| Length | 1 5/32 |
| 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 |
| Min. Tensile Strength (psi) | 160000 pounds per square inch |
| Specification Data | 80205-nas1581 professional/industrial association standard |
| Surface Treatment | Cadmium and chromate |
| Surface Treatment Specification | Qq-p-416, type 2, class2 fed spec all treatment responses |
| Thread Class | 3a |
| Thread Diameter | 0.250 |
| Thread Direction | Right-hand |
| Thread Length | 0.403 inches maximum |
| Thread Qty | 28 |
| Thread Qty Per Inch (tpi) | 28 |
| Thread Series Designator | UNJF |
| Thread Size | 1/4 |
| Weight | .005 lb |
Other sizes
Parts that share this base number, ordered by size. Always verify the full specification before substituting.
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.
- NAS1581C4T12 NAS 1/4-28 · 0.073 in · Flat countersunk · Steel
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Catalog data updated 2026-07-05. Report a data error