The Nut,tube Coupling, cataloged under National Stock Number 4730-01-238-4032, 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 15 specifications, cited from the U.S. Government catalog. 7 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government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 | 4730-01-238-4032 |
| Item Name | Nut,tube Coupling |
| FSC / FSG | 4730 / 47 — Hose, Pipe, Tube, Lubrication, and Railing Fittings |
| Status | ACTIVE |
| Length to Shoulder | 1.017 INCHES NOMINAL IN |
| Width Across Flats | 2.000 INCHES NOMINAL IN |
| Thread Series | UN |
| Thread Direction | RIGHT-HAND |
| Nominal Thread Size | 1.625 INCHES IN |
| Specification/standard Data | 96906 - MS51531 GOVERNMENT STANDARD AND 81349 - MIL-F-18866 GOVERNMENT STANDARD |
| Nondefinitive Spec/std Data | MS51531B20S REFERENCE NUMBER |
| Nut Height | 1.230 INCHES NOMINAL IN |
| Surface Treatment | PASSIVATE OVERALL |
| Nut Style | TUBE COUPLING |
| Thread Class | 2B |
| Thread Quantity Per Inch | 12 |
| Material | STEEL CORROSION RESISTING OVERALL |
| Smallest Inside Diameter | 1.344 INCHES NOMINAL IN |
| Nominal Tube Outside Diameter | 1.250 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 |
|---|---|
| MS51531B20S | 2/2 Government specification standardization U.S. Government activity |
| J514 | 5/9 Secondary reference U.S. Government activity |
| 20-BTX-SS | 5/9 Secondary reference U.S. Government activity |
| 20-BTX-SS | 5/1 Secondary reference Parker-Hannifin Corporation Dba Pneutronics Div Tube Fittings Division |
| 20 070110S | 5/9 Secondary reference U.S. Government activity |
| MIL-DTL-18866 | 4/1 Identification reference U.S. Government activity |
| MIL-F-18866 | 5/9 Secondary reference U.S. Government activity |
NSN 4730-01-238-4032 is a Nut,tube Coupling, classified under FSC 4730, Hose, Pipe, Tube, Lubrication, and Railing Fittings. Status: active.
1 possible match (shared part number, not a government interchangeability claim): 4730-01-541-4435. Verify interchangeability with system specifications before substitution.
Key specifications for 4730-01-238-4032: Length to Shoulder: 1.017 INCHES NOMINAL IN; Width Across Flats: 2.000 INCHES NOMINAL IN; Thread Series: UN; Thread Direction: RIGHT-HAND. 15 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.