The Screw,close Tolerance, cataloged under National Stock Number 5305-01-666-4638, is classified within Federal Supply Class 5305 (Screws) of the Hardware and Abrasives group. Government technical data includes 16 specifications, cited from the U.S. Government catalog. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5305-01-666-4638 |
| Item Name | Screw,close Tolerance |
| FSC / FSG | 5305 / 53 — Screws |
| Status | ACTIVE |
| Head Height | 0.057 INCHES NOMINAL IN |
| Fastener Length | 1.263 INCHES MINIMUM AND 1.293 INCHES MAXIMUM IN |
| Thread Length | 0.403 INCHES NOMINAL IN |
| Material Document and Classification | AMS4928 NATIONAL STD SINGLE MATERIAL RESPONSE OR AMS4967 NATIONAL STD SINGLE MATERIAL RESPONSE OVERALL |
| Nominal Thread Diameter | 0.2500 INCHES IN |
| Head Style | FLAT COUNTERSUNK |
| Thread Direction | RIGHT-HAND |
| Grip Length | 0.865 INCHES MINIMUM AND 0.885 INCHES MAXIMUM IN |
| Grip Diameter | 0.2646 INCHES MINIMUM AND 0.2651 INCHES MAXIMUM IN |
| Internal Drive Style | TORQUE-SET RIBBED |
| Countersink Angle | 99.0 DEGREES MINIMUM AND 101.0 DEGREES MAXIMUM |
| Thread Class | 3A A |
| Thread Quantity Per Inch | 28 |
| Material | TITANIUM ALLOY UNS R56400 OVERALL |
| Thread Series Designator | UNIFIED NATIONAL JOINT FINE (UNJF) |
| Head Diameter | 0.3988 INCHES NOMINAL 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 |
|---|---|
| NAS1581K4R14X | 3/2 Design control — primary reference U.S. Government activity |
NSN 5305-01-666-4638 is a Screw,close Tolerance, classified under FSC 5305, Screws. Status: active.
Key specifications for 5305-01-666-4638: Head Height: 0.057 INCHES NOMINAL IN; Fastener Length: 1.263 INCHES MINIMUM AND 1.293 INCHES MAXIMUM IN; Thread Length: 0.403 INCHES NOMINAL IN; Material Document and Classification: AMS4928 NATIONAL STD SINGLE MATERIAL RESPONSE OR AMS4967 NATIONAL STD SINGLE MATERIAL RESPONSE OVERALL. 16 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.