The Washer,concave, cataloged under National Stock Number 5310-01-256-9733, 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11 specifications, cited from the U.S. Government catalog. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 3 items share a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5310-01-256-9733 |
| Item Name | Washer,concave |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Status | ACTIVE |
| Surface Finish | 63.0 MICROINCHES BOTTOM |
| Surface Finish | 63.0 MICROINCHES TOP |
| Surface Treatment Document and Classification | QQ-P-416,TY2,CL2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Radius | 0.427 INCHES MINIMUM AND 0.447 INCHES MAXIMUM IN |
| Style Designator | CONCAVE |
| Material Document and Classification | MIL-S-5000 MIL SPEC SINGLE MATERIAL RESPONSE OVERALL |
| Outside Diameter | 0.458 INCHES MINIMUM AND 0.478 INCHES MAXIMUM IN |
| Surface Treatment | CADMIUM AND CHROMATE OVERALL |
| Minimum Tensile Strength | 145000 POUNDS PER SQUARE INCH LBS |
| Material | STEEL COMP E4340 OVERALL |
| Hole Diameter | 0.256 INCHES MINIMUM AND 0.276 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 |
|---|---|
| 140-030-1 | 3/2 Design control — primary reference U.S. Government activity |
NSN 5310-01-256-9733 is a Washer,concave, classified under FSC 5310, Nuts and Washers. Status: active.
3 possible matches (shared part number, not a government interchangeability claim): 5120-01-333-9004, 5310-01-594-1907, 7610-01-730-0157. Verify interchangeability with system specifications before substitution.
Key specifications for 5310-01-256-9733: Surface Finish: 63.0 MICROINCHES BOTTOM; Surface Finish: 63.0 MICROINCHES TOP; Surface Treatment Document and Classification: QQ-P-416,TY2,CL2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL; Radius: 0.427 INCHES MINIMUM AND 0.447 INCHES MAXIMUM IN. 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.