The Screw,cap,socket Head, cataloged under National Stock Number 5305-01-325-1973, is classified within Federal Supply Class 5305 (Screws) of the Hardware and Abrasives group. Government technical data includes 18 specifications, cited from the U.S. Government catalog. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5305-01-325-1973 |
| Item Name | Screw,cap,socket Head |
| FSC / FSG | 5305 / 53 — Screws |
| Status | ACTIVE |
| Width Across Flats | 0.312 INCHES NOMINAL IN |
| Head Height | 0.368 INCHES MINIMUM AND 0.375 INCHES MAXIMUM IN |
| Fastener Length | 3.500 INCHES NOMINAL IN |
| Thread Length | 1.250 INCHES NOMINAL IN |
| Hardness Rating | 39.0 ROCKWELL C MINIMUM AND 45.0 ROCKWELL C MAXIMUM OVERALL |
| Material Document and Classification | SAE GRADE 8 ASSN STD SINGLE MATERIAL RESPONSE OVERALL |
| Nominal Thread Diameter | 0.375 INCHES IN |
| Head Style | KNURLED NO. 1 |
| Thread Direction | RIGHT-HAND |
| Color | BLACK OVERALL |
| Surface Treatment | OXIDE OVERALL |
| Minimum Tensile Strength | 180000 POUNDS PER SQUARE INCH LBS |
| Internal Drive Style | HEXAGON |
| Thread Class | 2A A |
| Thread Quantity Per Inch | 16 |
| Material | STEEL OVERALL |
| Thread Series Designator | UNIFIED NATIONAL COARSE (UNC) |
| Head Diameter | 0.550 INCHES MINIMUM AND 0.562 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 |
|---|---|
| 91251A638 | 3/9 Design control — primary reference Mcmaster-Carr Supply Co |
NSN 5305-01-325-1973 is a Screw,cap,socket Head, classified under FSC 5305, Screws. Status: active.
1 possible match (shared part number, not a government interchangeability claim): 5305-01-597-1553. Verify interchangeability with system specifications before substitution.
Key specifications for 5305-01-325-1973: Width Across Flats: 0.312 INCHES NOMINAL IN; Head Height: 0.368 INCHES MINIMUM AND 0.375 INCHES MAXIMUM IN; Fastener Length: 3.500 INCHES NOMINAL IN; Thread Length: 1.250 INCHES NOMINAL IN. 18 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.