The Elbow,flange to Tube, cataloged under National Stock Number 4730-01-018-1681, 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 24 specifications, cited from the U.S. Government catalog. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 2 items share a part number with this NSN in the catalog (possible match — not a government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 | 4730-01-018-1681 |
| Item Name | Elbow,flange to Tube |
| FSC / FSG | 4730 / 47 — Hose, Pipe, Tube, Lubrication, and Railing Fittings |
| Status | ACTIVE |
| Flange Shape | TRIANGULAR WITH HOLES SECOND END |
| Flow Angle | 45.0 DEGREES |
| Flange Face Design | RAISED WITH CURVE AND RADIUS SECOND END |
| Connection Style | INVERTED FLARE (TUBE) FIRST END |
| Nominal Length | 0.370 INCHES SECOND END IN |
| Bolt Circle Nominal Diameter | 2.302 INCHES SECOND END IN |
| Connection Type | FLANGE SECOND END |
| Connection Type | THREADED EXTERNAL TUBE FIRST END |
| Thread Pitch Diameters | +1.6814 TO 1.7400 INCHES FIRST END IN |
| Material Document and Classification | AMS4212 ASSN STD ALL MATERIAL RESPONSES OVERALLUNABLE TO DECODE |
| Bolt Hole Nominal Diameter | 0.344 INCHES SECOND END IN |
| Nominal Outside Diameter Tube Accommodated | 1.565 INCHES FIRST ENDUNABLE TO DECODE IN |
| Leg Length | 1.237 INCHES NOMINAL SECOND END IN |
| Leg Length | 3.890 INCHES MINIMUM AND 3.990 INCHES MAXIMUM FIRST END IN |
| Nominal Thread Size | 1.750 INCHES FIRST END IN |
| Seat Angle | 25.0 DEGREES FIRST END |
| Bolt Hole Quantity | 3 SECOND END |
| Nominal Width | 1.516 INCHES SECOND END IN |
| Thread Quantity Per Inch | 12 FIRST END |
| Material | ALUMINUM ALLOY OVERALLUNABLE TO DECODE |
| Thread Series Designator | UNS FIRST END |
| Raised Face Nominal Diameter | 1.514 INCHES SECOND ENDUNABLE TO DECODE IN |
| Raised Face Nominal Height | 0.370 INCHES SECOND END IN |
| Nominal Thickness | 0.370 INCHES SECOND END 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 |
|---|---|
| 770018 | 5/9 Secondary reference American Tool and Machine Corp |
| 770018 | 5/9 Secondary reference Rtx Corporation Dba Pratt & Whitney Div Pratt &whitney |
| 770018 | 3/9 Design control — primary reference Turbo Power & Marine System Inc Sub of United Technologies Corp |
NSN 4730-01-018-1681 is a Elbow,flange to Tube, classified under FSC 4730, Hose, Pipe, Tube, Lubrication, and Railing Fittings. Status: active.
2 possible matches (shared part number, not a government interchangeability claim): 4240-01-250-3598, 5935-01-476-2853. Verify interchangeability with system specifications before substitution.
Key specifications for 4730-01-018-1681: Flange Shape: TRIANGULAR WITH HOLES SECOND END; Flow Angle: 45.0 DEGREES; Flange Face Design: RAISED WITH CURVE AND RADIUS SECOND END; Connection Style: INVERTED FLARE (TUBE) FIRST END. 24 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.