The Nut,tube Coupling, cataloged under National Stock Number 4730-00-555-8203, is classified within Federal Supply Class 4730 (No Item Name Available) of the Pipe, Tubing, Hose, and Fittings group. The primary manufacturer of record is Sae International Dba Sae International. Government technical data includes 18 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 22 commercial cross-references from 14 manufacturers, enabling identification through both NSN and commercial part number lookups. 8 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4730-00-555-8203 |
| Primary Part Number | MS21921-4D |
| Item Name | Nut,tube Coupling |
| FSC / FSG | 4730 / 47 — No Item Name Available |
| Manufacturer | Sae International Dba Sae International |
| Status | ACTIVE |
| Thread Class | 3B |
| Nominal Thread Size | 0.438 INCHES IN |
| Criticality Code Justification | FEAT |
| Material | ALUMINUM ALLOY 2014 OR ALUMINUM ALLOY 2024 OVERALL |
| Material Document and Classification | QQ-A-367,T6 FED SPEC SINGLE MATERIAL RESPONSE OR QQ-A-225/6,T6,T62 OR T851 FED SPEC SINGLE MATERIAL RESPONSE OVERALL |
| Thread Series | UNIFIED NATIONAL JOINT FINE (UNJF) |
| Seat Angle | 45.00 DEGREES NOMINAL |
| Thread Quantity Per Inch | 20 |
| Width Across Flats | 0.562 INCHES NOMINAL IN |
| Specification/standard Data | 96906-MS21921 GOVERNMENT STANDARD |
| Surface Treatment Document and Classification | MIL-A-8625,TYPE 2,CLASS 1 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Length to Shoulder | 0.537 INCHES MINIMUM AND 0.557 INCHES MAXIMUM IN |
| Smallest Inside Diameter | 0.300 INCHES MINIMUM AND 0.305 INCHES MAXIMUM IN |
| Surface Treatment | ANODIZE OVERALL |
| Nominal Tube Outside Diameter | 0.250 INCHES IN |
| Nut Style | TUBE COUPLING |
| Nut Height | 0.710 INCHES MINIMUM AND 0.730 INCHES MAXIMUM IN |
| Thread Direction | RIGHT-HAND |
| Acquisition Status | ACTIVE |
| HAZMAT | No |
| Part Number | Manufacturer |
|---|---|
| AS21921-4D | Society of Automotive Engineers Inc (USA) |
| AS18280 | Society of Automotive Engineers Inc (USA) |
| MS21921-4D | Society of Automotive Engineers Inc (USA) |
| 156/15 | Wellman Group (GBR) |
| AS21921 | Sae International Dba Sae International (USA) |
| DV600W4 | S-I Electronics Inc (USA) |
| MS21921-4D PRIMARY | Sae International Dba Sae International (USA) |
| AS21921 | Society of Automotive Engineers Inc (USA) |
| VSF1212-4WW | Fairchild Fasteners Europe - Vsd Gmbh (DEU) |
| AS18280 | Sae International Dba Sae International (USA) |
| 118-21600-230-4 | Designed Metal Connections Inc Dba Permaswage Usa Div Permaswage, a Pcc Company (USA) |
| 2652291W4 | Parker Hannifin Corporation Div Aerospace Group Headquarters (USA) |
| AS21921-4D PRIMARY | Sae International Dba Sae International (USA) |
| CVC4257W4 | Triumph Aerostructures, Llc Dba Triumph Aerostructures - Vought Integrated Programs Division (USA) |
| VSF1212-4WW | Howmet Global Fastening Systems Inc Div Torrance Operations (USA) |
| SAE-AS18280 | Sae International Dba Sae International (USA) |
| 118-21600-230-4 | Danfoss Power Solutions II, Llc (USA) |
| MS21921D4 | Military Standards Promulgated by Military Departments Under Authority of Defense Standardization Manual 4120 3-M |
| 118-21600-230-4 | Dana Corp Weatherhead Div (USA) |
| ER817-4D | Lockheed Martin Corporation Div Lockheed Martin Aeronautics Company (USA) |
NSN 4730-00-555-8203 is a Nut,tube Coupling, manufactured by Sae International Dba Sae International, classified under FSC 4730 (No Item Name Available). Status: active.
NSN 4730-00-555-8203 has 22 cross-referenced part numbers: AS21921-4D (Society of Automotive Engineers Inc), AS18280 (Society of Automotive Engineers Inc), MS21921-4D (Society of Automotive Engineers Inc), 156/15 (Wellman Group), AS21921 (Sae International Dba Sae International) and 17 more.
There are 8 known substitutes for 4730-00-555-8203: 4730-00-222-8636, 3030-00-481-3634, 6145-00-548-2424 and 5 more. Verify interchangeability with system specifications before substitution.
Key specifications for MS21921-4D: Thread Class: 3B; Nominal Thread Size: 0.438 INCHES IN; Criticality Code Justification: FEAT; Material: ALUMINUM ALLOY 2014 OR ALUMINUM ALLOY 2024 OVERALL. 20 total characteristics are documented in the Federal Logistics Information System.