The Nut,tube Coupling, cataloged under National Stock Number 4730-00-554-7061, is classified within Federal Supply Class 4730 (Hose, Pipe, Tube, Lubrication, and Railing Fittings) of the Pipe, Tubing, Hose, and Fittings group. The manufacturer of record is Rtx Corporation Dba Pratt & Whitney Div Pratt &whitney. Government technical data includes 18 specifications, cited from the U.S. Government catalog. The record lists 2 manufacturer part numbers 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through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 3 items share a part number with this NSN in the catalog (possible match — not a government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 | 4730-00-554-7061 |
| Primary Part Number | 311251 |
| Item Name | Nut,tube Coupling |
| FSC / FSG | 4730 / 47 — Hose, Pipe, Tube, Lubrication, and Railing Fittings |
| Manufacturer | Rtx Corporation Dba Pratt & Whitney Div Pratt &whitney |
| Status | ACTIVE |
| Length to Shoulder | 0.603 INCHES NOMINAL IN |
| Width Across Flats | 0.685 INCHES NOMINAL IN |
| Thread Series | UNF |
| Precious Material | SILVER |
| Precious Material and Weight | 0.200 SILVER GRAMS |
| Material Document and Classification | AMS 5649 ASSN STD SINGLE MATERIAL RESPONSE OVERALL |
| Thread Direction | RIGHT-HAND |
| Nominal Thread Size | 0.562 INCHES IN |
| Nut Height | 0.719 INCHES NOMINAL IN |
| Surface Treatment | SILVER OVERALL |
| Precious Material and Location | SURFACE SILVER |
| Nut Style | TUBE COUPLING |
| Thread Class | 3B |
| Thread Quantity Per Inch | 18 |
| Material | STEEL COMP 316 OVERALL |
| Fabrication Method | MACHINED |
| Smallest Inside Diameter | 0.442 INCHES NOMINAL IN |
| Nominal Tube Outside Diameter | 0.375 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 |
| Part Number | Manufacturer |
|---|---|
| 311251 | Kito Mfg Co. Ltd (JPN) |
| 311251 PRIMARY | Rtx Corporation Dba Pratt & Whitney Div Pratt &whitney (USA) |
| Reference | Meaning |
|---|---|
| 311251 | 5/9 Secondary reference Kito Mfg Co. Ltd |
| 311251 | 5/9 Secondary reference Turbo Power & Marine System Inc Sub of United Technologies Corp |
| 311251 | 5/9 Secondary reference Schering Laboratories Institutional Sales Dept K-11-3 L-5 |
NSN 4730-00-554-7061 is a Nut,tube Coupling, manufactured by Rtx Corporation Dba Pratt & Whitney Div Pratt &whitney, classified under FSC 4730, Hose, Pipe, Tube, Lubrication, and Railing Fittings. Status: active.
NSN 4730-00-554-7061 has 2 manufacturer part numbers on file: 311251 (Kito Mfg Co. Ltd), 311251 (Rtx Corporation Dba Pratt & Whitney Div Pratt &whitney).
3 possible matches (shared part number, not a government interchangeability claim): 5360-00-876-5517, 5365-01-091-1101, 6150-01-710-3123. Verify interchangeability with system specifications before substitution.
Key specifications for 311251: Length to Shoulder: 0.603 INCHES NOMINAL IN; Width Across Flats: 0.685 INCHES NOMINAL IN; Thread Series: UNF; Precious Material: SILVER. 18 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.