The Washer,flat, cataloged under National Stock Number 5310-00-545-9906, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. The manufacturer of record is Ditta Seguino Ambrogio. Government technical data includes 7 specifications, cited from the U.S. Government catalog. The record lists 3 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 6 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government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 | 5310-00-545-9906 |
| Primary Part Number | W21451 |
| Item Name | Washer,flat |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | Ditta Seguino Ambrogio |
| Status | ACTIVE |
| Overall Diameter | 1.934 INCHES NOMINAL IN |
| Cross-Sectional Shape Style | RECTANGULAR |
| Peripheral Shape Style | ROUND |
| Material | STEEL OVERALL |
| Center Hole Shape Style | ROUND |
| Hole Diameter | 1.125 INCHES NOMINAL IN |
| Thickness | 0.041 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 |
|---|---|
| W21451 | Ditta Seguino Ambrogio (ITA) |
| S/30215941 | Ditta Seguino Ambrogio (ITA) |
| 3W21451 | Curtiss-Wright Electro-Mechanical Corporation Dba Curtiss-Wright Steam and Air Solutions Div Steam and Air Solutions (USA) |
| Reference | Meaning |
|---|---|
| 30215941 | C/1 Advisory reference — outside the item-of-supply concept Zf Industrieantriebe Witten Gmbh |
| 3W21451 | 5/9 Secondary reference Ingersoll-Rand Company Dba Ingersoll-Rand |
| 3W21451 | 3/2 Design control — primary reference U.S. Government activity |
| 3W21451 | 5/9 Secondary reference U.S. Government activity |
| 3W21451 | 5/9 Secondary reference Ingersoll Rand Co |
| 3W21451 | 5/9 Secondary reference Siemens Energy, Inc. Dba Dresser-Rand |
NSN 5310-00-545-9906 is a Washer,flat, manufactured by Ditta Seguino Ambrogio, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-00-545-9906 has 3 manufacturer part numbers on file: W21451 (Ditta Seguino Ambrogio), S/30215941 (Ditta Seguino Ambrogio), 3W21451 (Curtiss-Wright Electro-Mechanical Corporation Dba Curtiss-Wright Steam and Air Solutions Div Steam and Air Solutions).
1 possible match (shared part number, not a government interchangeability claim): 4310-01-319-2780. Verify interchangeability with system specifications before substitution.
Key specifications for W21451: Overall Diameter: 1.934 INCHES NOMINAL IN; Cross-Sectional Shape Style: RECTANGULAR; Peripheral Shape Style: ROUND; Material: STEEL OVERALL. 7 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.