The Screw,shoulder, cataloged under National Stock Number 5305-01-657-0179, is classified within Federal Supply Class 5305 (Screws) of the Hardware and Abrasives group. Government technical data includes 14 specifications, cited from the U.S. Government catalog. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog.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 | 5305-01-657-0179 |
| Item Name | Screw,shoulder |
| FSC / FSG | 5305 / 53 — Screws |
| Status | ACTIVE |
| Width Across Flats | 0.250 INCHES NOMINAL IN |
| Head Height | 0.302 INCHES MINIMUM AND 0.312 INCHES MAXIMUM IN |
| Fastener Length | 2.500 INCHES NOMINAL IN |
| Thread Length | 0.625 INCHES NOMINAL IN |
| Nominal Thread Diameter | 0.500 INCHES IN |
| Head Style | FLAT CHAMFER |
| Thread Direction | RIGHT-HAND |
| Surface Treatment | ZINC AND CHROMATE OVERALL |
| Internal Drive Style | HEXAGON |
| Thread Class | 3A A |
| Thread Quantity Per Inch | 13 |
| Material | STEEL UNS K03104 OVERALL |
| Thread Series Designator | UNIFIED NATIONAL COARSE (UNC) |
| Head Diameter | 0.729 INCHES MINIMUM AND 0.750 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 |
|---|---|
| AES20U500B50BB3A81 | 3/2 Design control — primary reference U.S. Government activity |
| B18.24A-2006 | 3/1 Design control — primary reference The American Society of Mechanical Engineers |
NSN 5305-01-657-0179 is a Screw,shoulder, classified under FSC 5305, Screws. Status: active.
Key specifications for 5305-01-657-0179: Width Across Flats: 0.250 INCHES NOMINAL IN; Head Height: 0.302 INCHES MINIMUM AND 0.312 INCHES MAXIMUM IN; Fastener Length: 2.500 INCHES NOMINAL IN; Thread Length: 0.625 INCHES NOMINAL IN. 14 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.