The Nut,tube Coupling, cataloged under National Stock Number 4730-00-034-1411, 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 Sae International Dba Sae International. Government technical data includes 16 specifications, cited from the U.S. Government catalog. The record lists 1 manufacturer part number for this item, enabling identification through both NSN and commercial part number lookups. 11 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4730-00-034-1411 |
| Primary Part Number | MS21921-4K |
| Item Name | Nut,tube Coupling |
| FSC / FSG | 4730 / 47 — Hose, Pipe, Tube, Lubrication, and Railing Fittings |
| Manufacturer | Sae International Dba Sae International |
| Status | ACTIVE |
| Length to Shoulder | 0.547 INCHES NOMINAL IN |
| Width Across Flats | 0.562 INCHES NOMINAL IN |
| Thread Series | UNIFIED NATIONAL JOINT FINE (UNJF) |
| Material Document and Classification | QQ-S-763 FED SPEC SINGLE MATERIAL RESPONSE OVERALL |
| Seat Angle | 45.00 DEGREES NOMINAL |
| Thread Direction | RIGHT-HAND |
| Nominal Thread Size | 0.438 INCHES IN |
| Specification/standard Data | 96906-MS21921 GOVERNMENT STANDARD |
| Nut Height | 0.531 INCHES NOMINAL IN |
| Surface Treatment | PASSIVATE OVERALL |
| Nut Style | TUBE COUPLING |
| Thread Class | 3B |
| Thread Quantity Per Inch | 20 |
| Material | STEEL COMP 316 OVERALL |
| Smallest Inside Diameter | 0.300 INCHES NOMINAL IN |
| Nominal Tube Outside Diameter | 0.250 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 |
| Part Number | Manufacturer |
|---|---|
| MS21921-4K PRIMARY | Sae International Dba Sae International (USA) |
| Reference | Meaning |
|---|---|
| MS21921-4K | 5/9 Secondary reference Faber Enterprises, Inc. Div Faber Enterprise Inc |
| MS21921-4K | 5/9 Secondary reference Sps Technologies, Llc Dba Airdrome Precision Components |
| AS21921-4K | 5/9 Secondary reference Sae International Dba Sae International |
| MS21921-4K | 5/9 Secondary reference U.S. Government activity |
| AS21921-4K | 5/9 Secondary reference U.S. Government activity |
| AS21921 | 5/9 Secondary reference U.S. Government activity |
| MS21921-4K | 5/9 Secondary reference Designed Metal Connections Inc Dba Permaswage Usa Div Permaswage, a Pcc Company |
| MS21921-4K | 5/9 Secondary reference Eaton Aeroquip Llc Dba Jackson North 1 Div Fluid and Electrical Distribution |
| MS21921-4K | 5/9 Secondary reference Globe Aerospace Inc |
| SAE-AS18280 | 3/1 Design control — primary reference Sae International Dba Sae International |
| AS21921 | 5/9 Secondary reference Sae International Dba Sae International |
NSN 4730-00-034-1411 is a Nut,tube Coupling, manufactured by Sae International Dba Sae International, classified under FSC 4730, Hose, Pipe, Tube, Lubrication, and Railing Fittings. Status: active.
NSN 4730-00-034-1411 has 1 manufacturer part number on file: MS21921-4K (Sae International Dba Sae International).
Key specifications for MS21921-4K: Length to Shoulder: 0.547 INCHES NOMINAL IN; Width Across Flats: 0.562 INCHES NOMINAL IN; Thread Series: UNIFIED NATIONAL JOINT FINE (UNJF); Material Document and Classification: QQ-S-763 FED SPEC SINGLE MATERIAL RESPONSE OVERALL. 16 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.