The Screw,cap,socket Head, cataloged under National Stock Number 5305-01-577-4092, is classified within Federal Supply Class 5305 (Screws) of the Hardware and Abrasives group. The manufacturer of record is Mcmaster-Carr Supply Co. Government technical data includes 15 specifications, cited from the U.S. Government catalog. The record lists 1 manufacturer part number for this item, enabling identification through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5305-01-577-4092 |
| Primary Part Number | 91251A791 |
| Item Name | Screw,cap,socket Head |
| FSC / FSG | 5305 / 53 — Screws |
| Manufacturer | Mcmaster-Carr Supply Co |
| Status | ACTIVE |
| Width Across Flats | 0.500 INCHES NOMINAL IN |
| Head Height | 0.625 INCHES NOMINAL IN |
| Fastener Length | 0.500 INCHES NOMINAL IN |
| Thread Length | 0.500 INCHES NOMINAL IN |
| Nominal Thread Diameter | 0.625 INCHES IN |
| Head Style | FLAT CHAMFER |
| Thread Direction | RIGHT-HAND |
| Color | BLACK OVERALL |
| Surface Treatment | OXIDE OVERALL |
| Internal Drive Style | HEXAGON |
| Thread Class | 3A A |
| Thread Quantity Per Inch | 11 |
| Material | STEEL OVERALL |
| Thread Series Designator | UNIFIED NATIONAL COARSE (UNC) |
| Head Diameter | 0.938 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 |
| Part Number | Manufacturer |
|---|---|
| 91251A791 | Mcmaster-Carr Supply Co (USA) |
| Reference | Meaning |
|---|---|
| 91251A791 | 3/2 Design control — primary reference U.S. Government activity |
NSN 5305-01-577-4092 is a Screw,cap,socket Head, manufactured by Mcmaster-Carr Supply Co, classified under FSC 5305, Screws. Status: active.
NSN 5305-01-577-4092 has 1 manufacturer part number on file: 91251A791 (Mcmaster-Carr Supply Co).
Key specifications for 91251A791: Width Across Flats: 0.500 INCHES NOMINAL IN; Head Height: 0.625 INCHES NOMINAL IN; Fastener Length: 0.500 INCHES NOMINAL IN; Thread Length: 0.500 INCHES NOMINAL IN. 15 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.