PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

MS21921W4Nut,tube Coupling

Sae International Dba Sae International · NSN 4730-00-222-8636 · FSC 4730 · No Item Name Available
Verified by PartsTable
NSN 4730-00-222-8636 — this item is cataloged by the U.S. Government under National Stock Number 4730-00-222-8636. Primary manufacturer part number: MS21921W4.
Features
  • Nut,tube Coupling — FSC 4730
  • Material: ALUMINUM ALLOY 7075 OVERALL
  • Seat Angle: 45.00 DEGREES NOMINAL
  • Nut Height: 0.719 INCHES NOMINAL IN
  • Thread Quantity Per Inch: 20
  • Surface Treatment: ANODIZE OVERALL
  • Nominal Tube Outside Diameter: 0.250 INCHES IN
  • Length to Shoulder: 0.547 INCHES NOMINAL IN
Applications
  • Structural fastening and assembly
  • Equipment mounting
  • Panel and housing attachment
  • Fluid conveyance
  • Hydraulic system plumbing
General Description

The Nut,tube Coupling, cataloged under National Stock Number 4730-00-222-8636, 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 15 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 10 commercial cross-references from 3 manufacturers, enabling identification through both NSN and commercial part number lookups. 3 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Active.

Technical Specifications
ParameterValue
NSN4730-00-222-8636
Primary Part NumberMS21921W4
Item NameNut,tube Coupling
FSC / FSG4730 / 47 — No Item Name Available
ManufacturerSae International Dba Sae International
StatusACTIVE
MaterialALUMINUM ALLOY 7075 OVERALL
Seat Angle45.00 DEGREES NOMINAL
Nut Height0.719 INCHES NOMINAL IN
Thread Quantity Per Inch20
Surface TreatmentANODIZE OVERALL
Nominal Tube Outside Diameter0.250 INCHES IN
Length to Shoulder0.547 INCHES NOMINAL IN
Nominal Thread Size0.438 INCHES IN
Nut StyleTUBE COUPLING
Smallest Inside Diameter0.300 INCHES NOMINAL IN
Width Across Flats0.562 INCHES NOMINAL IN
Thread SeriesUNIFIED NATIONAL JOINT FINE (UNJF)
Thread DirectionRIGHT-HAND
Material Document and ClassificationQQ-A-225/9,T73 FED SPEC SINGLE MATERIAL RESPONSE OVERALL
Thread Class3B
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 3
4730-00-554-8015 INTERCHANGEABLE
Nut,tube Coupling
4730-00-555-8203AS21921-4D INTERCHANGEABLE
Nut,tube Coupling
Sae International Dba Sae International
4730-01-667-6443MS21921-4W INTERCHANGEABLE
Nut,tube Coupling
Sae International Dba Sae International
Cross-Reference Index
Part NumberManufacturer
SAE-AS18280 Sae International Dba Sae International (USA)
MS21921W4 Military Standards Promulgated by Military Departments Under Authority of Defense Standardization Manual 4120 3-M
MS21921D4 Military Standards Promulgated by Military Departments Under Authority of Defense Standardization Manual 4120 3-M
AS21921 Society of Automotive Engineers Inc (USA)
MS21921W4 PRIMARY Sae International Dba Sae International (USA)
MS21921-4W Military Standards Promulgated by Military Departments Under Authority of Defense Standardization Manual 4120 3-M
AS18280 Society of Automotive Engineers Inc (USA)
AS21921 Sae International Dba Sae International (USA)
AS18280 Sae International Dba Sae International (USA)
MS21921W4 Society of Automotive Engineers Inc (USA)
Related Parts
4730-00-554-8015INTERCHANGEABLE
NUT,TUBE COUPLING
4730-00-555-8203INTERCHANGEABLE
NUT,TUBE COUPLING
AS21921-4D
4730-01-667-6443INTERCHANGEABLE
NUT,TUBE COUPLING
MS21921-4W

Frequently Asked Questions

What is NSN 4730-00-222-8636?

NSN 4730-00-222-8636 is a Nut,tube Coupling, manufactured by Sae International Dba Sae International, classified under FSC 4730 (No Item Name Available). Status: active.

What are the part numbers for NSN 4730-00-222-8636?

NSN 4730-00-222-8636 has 10 cross-referenced part numbers: SAE-AS18280 (Sae International Dba Sae International), MS21921W4 (Military Standards Promulgated by Military Departments Under Authority of Defense Standardization Manual 4120 3-M), MS21921D4 (Military Standards Promulgated by Military Departments Under Authority of Defense Standardization Manual 4120 3-M), AS21921 (Society of Automotive Engineers Inc), MS21921W4 (Sae International Dba Sae International) and 5 more.

What NSN replaces 4730-00-222-8636?

There are 3 known substitutes for 4730-00-222-8636: 4730-00-554-8015, 4730-00-555-8203, 4730-01-667-6443. Verify interchangeability with system specifications before substitution.

What are the specifications of MS21921W4?

Key specifications for MS21921W4: Material: ALUMINUM ALLOY 7075 OVERALL; Seat Angle: 45.00 DEGREES NOMINAL; Nut Height: 0.719 INCHES NOMINAL IN; Thread Quantity Per Inch: 20. 15 total characteristics are documented in the Federal Logistics Information System.

Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
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