The Nut,tube Coupling, cataloged under National Stock Number 4730-01-087-7557, 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 14 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through both NSN and commercial part number lookups. 4 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4730-01-087-7557 |
| Primary Part Number | MS21921-8D |
| 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 | 0.599 INCHES MINIMUM AND 0.619 INCHES MAXIMUM IN |
| Width Across Flats | 0.871 INCHES MINIMUM AND 0.875 INCHES MAXIMUM IN |
| Thread Series | UNIFIED NATIONAL JOINT FINE (UNJF) |
| Seat Angle | 45.0 DEGREES NOMINAL |
| Thread Direction | RIGHT-HAND |
| Nominal Thread Size | 0.750 INCHES IN |
| Specification/standard Data | 96906-MS21921 GOVERNMENT STANDARD |
| Nut Height | 0.850 INCHES MINIMUM AND 0.870 INCHES MAXIMUM IN |
| Nut Style | TUBE COUPLING |
| Thread Class | 3B |
| Thread Quantity Per Inch | 16 |
| Material | ALUMINUM ALLOY 2014 AND ALUMINUM ALLOY 2024 OVERALL |
| Smallest Inside Diameter | 0.552 INCHES MINIMUM AND 0.557 INCHES MAXIMUM IN |
| Nominal Tube Outside Diameter | 0.500 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 |
| Part Number | Manufacturer |
|---|---|
| MS21921-8D PRIMARY | Sae International Dba Sae International (USA) |
| Reference | Meaning |
|---|---|
| MS21921-8D | 5/9 Secondary reference U.S. Government activity |
| AS21921 | 3/1 Design control — primary reference Sae International Dba Sae International |
| MS21921-8D | 5/9 Secondary reference U.S. Government activity |
| AS21921 | 5/9 Secondary reference U.S. Government activity |
NSN 4730-01-087-7557 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 4730-01-087-7557 has 1 manufacturer part number on file: MS21921-8D (Sae International Dba Sae International).
Key specifications for MS21921-8D: Length to Shoulder: 0.599 INCHES MINIMUM AND 0.619 INCHES MAXIMUM IN; Width Across Flats: 0.871 INCHES MINIMUM AND 0.875 INCHES MAXIMUM IN; Thread Series: UNIFIED NATIONAL JOINT FINE (UNJF); Seat Angle: 45.0 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.