The Washer,flat, cataloged under National Stock Number 5310-01-273-1639, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. Government technical data includes 10 specifications, cited from the U.S. Government catalog. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government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 | 5310-01-273-1639 |
| Item Name | Washer,flat |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Status | ACTIVE |
| Surface Treatment Document and Classification | QQ-P-416,TY 2,CL 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Overall Diameter | 0.475 INCHES MINIMUM AND 0.495 INCHES MAXIMUM IN |
| Material Document and Classification | AMS 5525 ASSN STD SINGLE MATERIAL RESPONSE OVERALL |
| Cross-Sectional Shape Style | RECTANGULAR |
| Surface Treatment | CADMIUM AND CHROMATE OVERALL |
| Peripheral Shape Style | ROUND |
| Material | IRON ALLOY 660 OVERALL |
| Center Hole Shape Style | ROUND |
| Hole Diameter | 0.251 INCHES MINIMUM AND 0.262 INCHES MAXIMUM IN |
| Thickness | 0.057 INCHES MINIMUM AND 0.069 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 |
|---|---|
| BACW10BN4SP | 3/2 Design control — primary reference U.S. Government activity |
NSN 5310-01-273-1639 is a Washer,flat, classified under FSC 5310, Nuts and Washers. Status: active.
1 possible match (shared part number, not a government interchangeability claim): 5310-01-669-7013. Verify interchangeability with system specifications before substitution.
Key specifications for 5310-01-273-1639: Surface Treatment Document and Classification: QQ-P-416,TY 2,CL 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL; Overall Diameter: 0.475 INCHES MINIMUM AND 0.495 INCHES MAXIMUM IN; Material Document and Classification: AMS 5525 ASSN STD SINGLE MATERIAL RESPONSE OVERALL; Cross-Sectional Shape Style: RECTANGULAR. 10 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.