The Washer,flat, cataloged under National Stock Number 5310-00-273-7670, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. The manufacturer of record is Stewart-Warner Corporation. Government technical data includes 9 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog.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 | 5310-00-273-7670 |
| Primary Part Number | 311288 |
| Item Name | Washer,flat |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | Stewart-Warner Corporation |
| Status | ACTIVE |
| Overall Diameter | 0.360 INCHES MINIMUM AND 0.365 INCHES MAXIMUM IN |
| Hardness Rating | 47.0 ROCKWELL C MINIMUM AND 50.0 ROCKWELL C MAXIMUM |
| Cross-Sectional Shape Style | RECTANGULAR |
| Surface Treatment | NICKEL OVERALL |
| Peripheral Shape Style | ROUND |
| Material | STEEL OVERALL |
| Center Hole Shape Style | ROUND |
| Hole Diameter | 0.175 INCHES MINIMUM AND 0.181 INCHES MAXIMUM IN |
| Thickness | 0.049 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 |
|---|---|
| 311288 PRIMARY | Stewart-Warner Corporation (USA) |
| Reference | Meaning |
|---|---|
| 311288 | 5/9 Secondary reference Stewart-Warner Alemite Sales Co Inc |
NSN 5310-00-273-7670 is a Washer,flat, manufactured by Stewart-Warner Corporation, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-00-273-7670 has 1 manufacturer part number on file: 311288 (Stewart-Warner Corporation).
Key specifications for 311288: Overall Diameter: 0.360 INCHES MINIMUM AND 0.365 INCHES MAXIMUM IN; Hardness Rating: 47.0 ROCKWELL C MINIMUM AND 50.0 ROCKWELL C MAXIMUM; Cross-Sectional Shape Style: RECTANGULAR; Surface Treatment: NICKEL 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.