The Screw,cap,socket Head, cataloged under National Stock Number 5305-01-121-1663, is classified within Federal Supply Class 5305 (Screws) of the Hardware and Abrasives group. Government technical data includes 19 specifications, cited from the U.S. Government catalog. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5305-01-121-1663 |
| Item Name | Screw,cap,socket Head |
| FSC / FSG | 5305 / 53 — Screws |
| Status | ACTIVE |
| Width Across Flats | 0.250 INCHES MINIMUM AND 0.253 INCHES MAXIMUM IN |
| Head Height | 0.305 INCHES MINIMUM AND 0.313 INCHES MAXIMUM IN |
| Fastener Length | 0.470 INCHES MINIMUM AND 0.500 INCHES MAXIMUM IN |
| Surface Treatment Document and Classification | MIL-C-13924,CL4 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Thread Length | 0.359 INCHES MINIMUM AND 0.500 INCHES MAXIMUM IN |
| Hardness Rating | 80.0 ROCKWELL B MINIMUM OVERALL |
| Nominal Thread Diameter | 0.312 INCHES IN |
| Head Style | FLAT CHAMFER |
| Thread Direction | RIGHT-HAND |
| Nondefinitive Spec/std Data | 6 TYPE |
| Surface Treatment | OXIDE OVERALL |
| Minimum Tensile Strength | 80000 POUNDS PER SQUARE INCH LBS |
| Minimum Yield Strength | 30000 POUNDS PER SQUARE INCH LBS |
| Internal Drive Style | HEXAGON |
| Thread Class | 3A A |
| Thread Quantity Per Inch | 18 |
| Material | STEEL COMP 302 OR STEEL COMP 303 OR STEEL COMP 304 OR STEEL COMP 305 OR STEEL COMP 316 OVERALL |
| Thread Series Designator | UNIFIED NATIONAL COARSE (UNC) |
| Head Diameter | 0.457 INCHES MINIMUM AND 0.469 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 |
|---|---|
| MS16995-62B | 5/9 Secondary reference U.S. Government activity |
| MS16995-62B | 3/2 Design control — primary reference U.S. Government activity |
| FF-S-86 | 4/1 Identification reference U.S. Government activity |
NSN 5305-01-121-1663 is a Screw,cap,socket Head, classified under FSC 5305, Screws. Status: active.
Key specifications for 5305-01-121-1663: Width Across Flats: 0.250 INCHES MINIMUM AND 0.253 INCHES MAXIMUM IN; Head Height: 0.305 INCHES MINIMUM AND 0.313 INCHES MAXIMUM IN; Fastener Length: 0.470 INCHES MINIMUM AND 0.500 INCHES MAXIMUM IN; Surface Treatment Document and Classification: MIL-C-13924,CL4 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL. 19 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.