PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

MS21937-4LPacking Nut

Sae International Dba Sae International · NSN 4730-00-821-0189 · FSC 4730 · No Item Name Available
Verified by PartsTable
NSN 4730-00-821-0189 — this item is cataloged by the U.S. Government under National Stock Number 4730-00-821-0189. Primary manufacturer part number: MS21937-4L.
Features
  • Packing Nut — FSC 4730
  • Thread Direction: RIGHT-HAND
  • Screw Thread Location: INTERNAL
  • Specification/standard Data: 81343-SAE AS21937 MANUFACTURERS STANDARD
  • Width Across Flats: 1.000 INCHES NOMINAL IN
  • Major Unthreaded Outside Diameter: 0.687 INCHES NOMINAL IN
  • Style Designator: HEXAGON, INTERNAL THREAD, SHOULDERED
  • Length to Shoulder: 0.344 INCHES NOMINAL IN
Applications
  • Structural fastening and assembly
  • Equipment mounting
  • Panel and housing attachment
  • Applications requiring Aluminum Alloy 7075 construction
General Description

The Packing Nut, cataloged under National Stock Number 4730-00-821-0189, 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 18 commercial cross-references from 14 manufacturers, enabling identification through both NSN and commercial part number lookups. 3 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Cancelled.

Technical Specifications
ParameterValue
NSN4730-00-821-0189
Primary Part NumberMS21937-4L
Item NamePacking Nut
FSC / FSG4730 / 47 — No Item Name Available
ManufacturerSae International Dba Sae International
StatusCANCELLED
Thread DirectionRIGHT-HAND
Screw Thread LocationINTERNAL
Specification/standard Data81343-SAE AS21937 MANUFACTURERS STANDARD
Width Across Flats1.000 INCHES NOMINAL IN
Major Unthreaded Outside Diameter0.687 INCHES NOMINAL IN
Style DesignatorHEXAGON, INTERNAL THREAD, SHOULDERED
Length to Shoulder0.344 INCHES NOMINAL IN
MaterialALUMINUM ALLOY 7075
Thread Length0.250 INCHES NOMINAL IN
Screw Thread Series DesignatorUNF
Thread Size7/16IN-20 IN
Largest Inside Diameter0.562 INCHES NOMINAL IN
Unthreaded Portion Length0.156 INCHES NOMINAL IN
Casehardening IndicatorNOT CASEHARDENED
Thread Class3B
Lifecycle & Compliance
Acquisition StatusCANCELLED
HAZMATNo
Verified Substitutes 3
4730-00-433-2974MS21937-5H INTERCHANGEABLE
Packing Nut
Precision Form Rivet Inc
4730-00-541-2173MS21937W8H INTERCHANGEABLE
Packing Nut
Sae International Dba Sae International
4730-00-684-0564MS21937W4H INTERCHANGEABLE
Packing Nut
Sae International Dba Sae International
Cross-Reference Index
Part NumberManufacturer
AS18280 Sae International Dba Sae International (USA)
MS21937-4L Chicago Pneumatic Tool Co (USA)
AS21937 Sae International Dba Sae International (USA)
MS21937-4L Parker Hannifin Corp Stratoflex Div Aircraft Fittings Opn (USA)
MS21937-4L Military Standards Promulgated by Military Departments Under Authority of Defense Standardization Manual 4120 3-M
MS21937-4L Eaton Aeroquip Llc Dba Jackson North 1 Div Fluid and Electrical Distribution (USA)
MS21937-4L Collins Engineering Corp (USA)
AS18280 Society of Automotive Engineers Inc (USA)
AS21937 Society of Automotive Engineers Inc (USA)
MS21937-4L Parker-Hannifin Corporation Dba Pneutronics Div Corporate Headquarters (USA)
MS21937-4L Danfoss Power Solutions II, Llc (USA)
SAE-AS18280 Sae International Dba Sae International (USA)
MS21937-4L PRIMARY Sae International Dba Sae International (USA)
MS21937-4L Faber Enterprises, Inc. Div Faber Enterprise Inc (USA)
MS21937-4L Satair A/s (DNK)
MS21937-4L Safran Aerosystems Ex Safran Aerotechnics Rlm (FRA)
MS21937-4L Globe Aerospace Inc (USA)
105-01495 Dana Corp Weatherhead Div (USA)
Related Parts
4730-00-433-2974INTERCHANGEABLE
PACKING NUT
MS21937-5H
4730-00-541-2173INTERCHANGEABLE
PACKING NUT
MS21937W8H
4730-00-684-0564INTERCHANGEABLE
PACKING NUT
MS21937W4H

Frequently Asked Questions

What is NSN 4730-00-821-0189?

NSN 4730-00-821-0189 is a Packing Nut, manufactured by Sae International Dba Sae International, classified under FSC 4730 (No Item Name Available). Status: cancelled.

What are the part numbers for NSN 4730-00-821-0189?

NSN 4730-00-821-0189 has 18 cross-referenced part numbers: AS18280 (Sae International Dba Sae International), MS21937-4L (Chicago Pneumatic Tool Co), AS21937 (Sae International Dba Sae International), MS21937-4L (Parker Hannifin Corp Stratoflex Div Aircraft Fittings Opn), MS21937-4L (Military Standards Promulgated by Military Departments Under Authority of Defense Standardization Manual 4120 3-M) and 13 more.

What NSN replaces 4730-00-821-0189?

There are 3 known substitutes for 4730-00-821-0189: 4730-00-433-2974, 4730-00-541-2173, 4730-00-684-0564. Verify interchangeability with system specifications before substitution.

What are the specifications of MS21937-4L?

Key specifications for MS21937-4L: Thread Direction: RIGHT-HAND; Screw Thread Location: INTERNAL; Specification/standard Data: 81343-SAE AS21937 MANUFACTURERS STANDARD; Width Across Flats: 1.000 INCHES NOMINAL IN. 16 total characteristics are documented in the Federal Logistics Information System.

Is NSN 4730-00-821-0189 still in active supply?

NSN 4730-00-821-0189 is currently cancelled. Check with the Defense Logistics Agency for current availability and authorized substitutes.

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