The Washer,flat, cataloged under National Stock Number 5310-00-481-0139, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. The manufacturer of record is Fm Af, Llc Dba American Fan Company. Government technical data includes 6 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through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5310-00-481-0139 |
| Primary Part Number | 4W33551P4 |
| Item Name | Washer,flat |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | Fm Af, Llc Dba American Fan Company |
| Status | ACTIVE |
| Width Across Flats | 1.375 INCHES NOMINAL IN |
| Cross-Sectional Shape Style | RECTANGULAR |
| Peripheral Shape Style | SQUARE |
| Center Hole Shape Style | ROUND |
| Hole Diameter | 0.562 INCHES NOMINAL IN |
| Thickness | 0.062 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 |
|---|---|
| 4W33551P4 PRIMARY | Fm Af, Llc Dba American Fan Company (USA) |
| Reference | Meaning |
|---|---|
| 4W-33551-4 | C/1 Advisory reference — outside the item-of-supply concept Zf Industrieantriebe Witten Gmbh |
| 58E151040P39 | 5/9 Secondary reference U.S. Government activity |
| 4W33551P4 | 3/9 Design control — primary reference New Philadelphia Fan Co Buffalo Forge Marine Fans |
NSN 5310-00-481-0139 is a Washer,flat, manufactured by Fm Af, Llc Dba American Fan Company, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-00-481-0139 has 1 manufacturer part number on file: 4W33551P4 (Fm Af, Llc Dba American Fan Company).
Key specifications for 4W33551P4: Width Across Flats: 1.375 INCHES NOMINAL IN; Cross-Sectional Shape Style: RECTANGULAR; Peripheral Shape Style: SQUARE; Center Hole Shape Style: ROUND. 6 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.