The Nut,tube Coupling,reducing, cataloged under National Stock Number 4730-00-203-3363, is classified within Federal Supply Class 4730 (Hose, Pipe, Tube, Lubrication, and Railing Fittings) of the Pipe, Tubing, Hose, and Fittings group. Government technical data includes 14 specifications, cited from the U.S. Government catalog. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 3 items share a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4730-00-203-3363 |
| Item Name | Nut,tube Coupling,reducing |
| FSC / FSG | 4730 / 47 — Hose, Pipe, Tube, Lubrication, and Railing Fittings |
| Status | ACTIVE |
| Length to Shoulder | 2.875 INCHES NOMINAL IN |
| Width Across Flats | 4.250 INCHES NOMINAL IN |
| Thread Series | UN |
| Seat Angle | 41.00 DEGREES NOMINAL |
| Thread Direction | RIGHT-HAND |
| Nominal Thread Size | 3.500 INCHES IN |
| Nut Height | 3.625 INCHES NOMINAL IN |
| Nut Style | TUBE COUPLING |
| Thread Class | 1B |
| Thread Quantity Per Inch | 12 |
| Material | ALUMINUM OVERALL |
| Fabrication Method | CAST |
| Smallest Inside Diameter | 2.563 INCHES NOMINAL IN |
| Nominal Tube Outside Diameter | 2.500 INCHES 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 |
|---|---|
| RE66F499PC5 | 3/2 Design control — primary reference U.S. Government activity |
| RE66F499 | D/9 Drawing number reference only U.S. Government activity |
NSN 4730-00-203-3363 is a Nut,tube Coupling,reducing, classified under FSC 4730, Hose, Pipe, Tube, Lubrication, and Railing Fittings. Status: active.
3 possible matches (shared part number, not a government interchangeability claim): 4730-00-203-3434, 5985-00-369-5530, 5310-00-568-7823. Verify interchangeability with system specifications before substitution.
Key specifications for 4730-00-203-3363: Length to Shoulder: 2.875 INCHES NOMINAL IN; Width Across Flats: 4.250 INCHES NOMINAL IN; Thread Series: UN; Seat Angle: 41.00 DEGREES NOMINAL. 14 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.