The Washer,flat, cataloged under National Stock Number 5310-01-657-3300, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. The manufacturer of record is Oshkosh Defense Llc. Government technical data includes 10 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog.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 | 5310-01-657-3300 |
| Primary Part Number | 4028881037 |
| Item Name | Washer,flat |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | Oshkosh Defense Llc |
| Status | ACTIVE |
| Overall Diameter | 1.492 INCHES MINIMUM AND 1.529 INCHES MAXIMUM IN |
| Material Document and Classification | ASTM F844 ASSN STD SINGLE MATERIAL RESPONSE OVERALL |
| Cross-Sectional Shape Style | RECTANGULAR |
| Color | BLACK OVERALL |
| Surface Treatment | PHOSPHATE AND ZINC OVERALL |
| Peripheral Shape Style | ROUND |
| Material | STEEL OVERALL |
| Center Hole Shape Style | ROUND |
| Hole Diameter | 0.525 INCHES MINIMUM AND 0.545 INCHES MAXIMUM IN |
| Thickness | 0.047 INCHES MINIMUM AND 0.080 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 |
| Part Number | Manufacturer |
|---|---|
| 4028881037 PRIMARY | Oshkosh Defense Llc (USA) |
| Reference | Meaning |
|---|---|
| 4028881 | D/9 Drawing number reference only Oshkosh Defense Llc |
NSN 5310-01-657-3300 is a Washer,flat, manufactured by Oshkosh Defense Llc, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-01-657-3300 has 1 manufacturer part number on file: 4028881037 (Oshkosh Defense Llc).
Key specifications for 4028881037: Overall Diameter: 1.492 INCHES MINIMUM AND 1.529 INCHES MAXIMUM IN; Material Document and Classification: ASTM F844 ASSN STD SINGLE MATERIAL RESPONSE OVERALL; Cross-Sectional Shape Style: RECTANGULAR; Color: BLACK OVERALL. 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.