The Screw,close Tolerance, cataloged under National Stock Number 5305-01-421-2540, is classified within Federal Supply Class 5305 (Screws) of the Hardware and Abrasives group. Government technical data includes 21 specifications, cited from the U.S. Government catalog. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5305-01-421-2540 |
| Item Name | Screw,close Tolerance |
| FSC / FSG | 5305 / 53 — Screws |
| Status | ACTIVE |
| Surface Finish | 32.0 MICROINCHES THREADS |
| Surface Finish | 32.0 MICROINCHES GRIP |
| Fastener Length | 2.091 INCHES NOMINAL IN |
| Surface Treatment Document and Classification | QQ-P-416,TY2,CL2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Thread Length | 0.403 INCHES NOMINAL IN |
| Material Document and Classification | 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 OVERALL |
| Nominal Thread Diameter | 0.250 INCHES IN |
| Head Style | FLAT COUNTERSUNK |
| Thread Direction | RIGHT-HAND |
| Specification/standard Data | 80205-NAS1581 PROFESSIONAL/INDUSTRIAL ASSOCIATION STANDARD |
| Grip Length | 1.615 INCHES MINIMUM AND 1.635 INCHES MAXIMUM IN |
| Grip Diameter | 0.248 INCHES MINIMUM AND 0.249 INCHES MAXIMUM IN |
| Surface Treatment | CADMIUM AND CHROMATE OVERALL |
| Minimum Tensile Strength | 160000 POUNDS PER SQUARE INCH LBS |
| Internal Drive Style | OFFSET CRUCIFORM (TORQUE SET) |
| Countersink Angle | 99.0 DEGREES MINIMUM AND 101.0 DEGREES MAXIMUM |
| Thread Class | 3A A |
| Thread Quantity Per Inch | 28 |
| Material | STEEL COMP 4140 OR STEEL COMP E4340 OR STEEL COMP 8740 OVERALL |
| Thread Series Designator | UNIFIED NATIONAL JOINT FINE (UNJF) |
| Head Diameter | 0.350 INCHES MINIMUM AND 0.399 INCHES MAXIMUM IN |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Reference | Meaning |
|---|---|
| NAS1581F4T27 | 3/2 Design control — primary reference U.S. Government activity |
| NAS1581A4T27 | 5/9 Secondary reference U.S. Government activity |
NSN 5305-01-421-2540 is a Screw,close Tolerance, classified under FSC 5305, Screws. Status: active.
Key specifications for 5305-01-421-2540: Surface Finish: 32.0 MICROINCHES THREADS; Surface Finish: 32.0 MICROINCHES GRIP; Fastener Length: 2.091 INCHES NOMINAL IN; Surface Treatment Document and Classification: QQ-P-416,TY2,CL2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL. 21 specifications are documented in the U.S. Government catalog.
No hazard code in the DLA record (HMIC N). Hazard information on this page is shown exactly as it appears in the DLA record.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-16.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.