The Nut,plain,castellated,hexagon, cataloged under National Stock Number 5310-00-021-8599, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. Government technical data includes 11 specifications, cited from the U.S. Government catalog. 6 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government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 | 5310-00-021-8599 |
| Item Name | Nut,plain,castellated,hexagon |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Status | ACTIVE |
| Width Across Flats | 0.750 INCHES NOMINAL IN |
| Thread Series | UNF |
| Material Document and Classification | QQ-S-624 FED SPEC SINGLE MATERIAL RESPONSE OVERALL |
| Thread Direction | RIGHT-HAND |
| Nominal Thread Size | 0.500 INCHES IN |
| Nut Height | 0.563 INCHES NOMINAL IN |
| Nut Style | CASTELLATED, HEXAGON |
| Thread Class | 2B |
| Thread Quantity Per Inch | 20 |
| Material | STEEL OVERALL |
| Bearing Surface Type | CHAMFERED OR WASHER FACED |
| 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 |
|---|---|
| 218599 | 5/9 Secondary reference CAGE 00000 |
| BBFX1EA | 5/9 Secondary reference CAGE 00000 |
| FFB571TYPEA | 4/1 Identification reference U.S. Government activity |
| Y335 | 5/9 Secondary reference Dresser Industries Inc P and M Mfg Div |
| B19444E | 5/9 Secondary reference CAGE 00000 |
| B167871AA | 5/9 Secondary reference CAGE 00000 |
NSN 5310-00-021-8599 is a Nut,plain,castellated,hexagon, classified under FSC 5310, Nuts and Washers. Status: active.
1 possible match (shared part number, not a government interchangeability claim): 5305-01-265-4911. Verify interchangeability with system specifications before substitution.
Key specifications for 5310-00-021-8599: Width Across Flats: 0.750 INCHES NOMINAL IN; Thread Series: UNF; Material Document and Classification: QQ-S-624 FED SPEC SINGLE MATERIAL RESPONSE OVERALL; Thread Direction: RIGHT-HAND. 11 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.