The Screw,cap,socket Head, cataloged under National Stock Number 5305-01-321-2391, 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19 specifications, cited from the U.S. Government catalog. 4 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5305-01-321-2391 |
| Item Name | Screw,cap,socket Head |
| FSC / FSG | 5305 / 53 — Screws |
| Status | ACTIVE |
| Width Across Flats | 0.125 INCHES NOMINAL IN |
| Fastener Length | 0.470 INCHES MINIMUM AND 0.500 INCHES MAXIMUM IN |
| Surface Treatment Document and Classification | ASTM A633 TY 2 CL 3 ASSN STD SINGLE TREATMENT RESPONSE OVERALL |
| Thread Length | 0.346 INCHES MINIMUM AND 0.429 INCHES MAXIMUM IN |
| Hardness Rating | 39.0 ROCKWELL C MINIMUM AND 45.0 ROCKWELL C MAXIMUM OVERALL |
| Material Document and Classification | ASTM A574, 1300 SERIES ASSN STD ALL MATERIAL RESPONSES OVERALL |
| Nominal Thread Diameter | 0.190 INCHES IN |
| Head Style | FLAT COUNTERSUNK |
| Thread Direction | RIGHT-HAND |
| Nondefinitive Spec/std Data | 4 TYPE |
| Surface Treatment | ZINC AND CHROMATE OVERALL |
| Minimum Tensile Strength | 180000 POUNDS PER SQUARE INCH LBS |
| Internal Drive Style | HEXAGON |
| Countersink Angle | 80.0 DEGREES MINIMUM AND 82.0 DEGREES MAXIMUM |
| Thread Class | 3A A |
| Thread Quantity Per Inch | 24 |
| Material | STEEL OVERALL |
| Thread Series Designator | UNIFIED NATIONAL COARSE (UNC) |
| Head Diameter | 0.359 INCHES MINIMUM AND 0.411 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 |
|---|---|
| 3176209-A-042 | 3/9 Design control — primary reference Navair and Navsea Managed Original Design Activity Dwg Not Material/parts Supplier |
| 317209-A-042 | 5/9 Secondary reference Navair and Navsea Managed Original Design Activity Dwg Not Material/parts Supplier |
| FF-S-86 | 4/1 Identification reference U.S. Government activity |
| NS24667-20Z | 5/9 Secondary reference U.S. Government activity |
NSN 5305-01-321-2391 is a Screw,cap,socket Head, classified under FSC 5305, Screws. Status: active.
Key specifications for 5305-01-321-2391: Width Across Flats: 0.125 INCHES NOMINAL IN; Fastener Length: 0.470 INCHES MINIMUM AND 0.500 INCHES MAXIMUM IN; Surface Treatment Document and Classification: ASTM A633 TY 2 CL 3 ASSN STD SINGLE TREATMENT RESPONSE OVERALL; Thread Length: 0.346 INCHES MINIMUM AND 0.429 INCHES MAXIMUM IN. 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.