The Washer,lock, cataloged under National Stock Number 5310-00-237-6781, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. Government technical data includes 9 specifications, cited from the U.S. Government catalog. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5310-00-237-6781 |
| Item Name | Washer,lock |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Status | ACTIVE |
| Surface Treatment Document and Classification | MIL-F-495 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Hardness Rating | 86.0 ROCKWELL B MINIMUM AND 92.0 ROCKWELL B MAXIMUM |
| Style Designator | FLAT EXTERNAL AND INTERNAL TEETH |
| Material Document and Classification | QQ-B-750 TEMPER EXTRA HARD FED SPEC SINGLE MATERIAL RESPONSE OVERALL |
| Outside Diameter | 0.670 INCHES MINIMUM AND 0.700 INCHES MAXIMUM IN |
| Material Thickness | 0.032 INCHES MINIMUM AND 0.040 INCHES MAXIMUM IN |
| Surface Treatment | OXIDE FILM OVERALL |
| Material | COPPER ALLOY OVERALL |
| Hole Diameter | 0.256 INCHES MINIMUM AND 0.295 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 |
|---|---|
| SM-B-745222 | D/9 Drawing number reference only U.S. Government activity |
| SMB745222-2 | 3/2 Design control — primary reference U.S. Government activity |
NSN 5310-00-237-6781 is a Washer,lock, classified under FSC 5310, Nuts and Washers. Status: active.
Key specifications for 5310-00-237-6781: Surface Treatment Document and Classification: MIL-F-495 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL; Hardness Rating: 86.0 ROCKWELL B MINIMUM AND 92.0 ROCKWELL B MAXIMUM; Style Designator: FLAT EXTERNAL AND INTERNAL TEETH; Material Document and Classification: QQ-B-750 TEMPER EXTRA HARD FED SPEC SINGLE MATERIAL RESPONSE OVERALL. 9 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.