PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

21738-3Tee,boss

Rockwell Collins Inc · NSN 4730-00-201-9591 · FSC 4730 · No Item Name Available
Verified by PartsTable
NSN 4730-00-201-9591 — this item is cataloged by the U.S. Government under National Stock Number 4730-00-201-9591. Primary manufacturer part number: 21738-3.
Features
  • Tee,boss — FSC 4730
  • Material Document and Classification: QQ-A-225/8,T651 FED SPEC SINGLE MATERIAL RESPONSE OVERALL
  • Connection Type: THREADED INTERNAL BOSS ALL ENDS
  • Leg Length: 0.683 INCHES NOMINAL SECOND END IN
  • Material: ALUMINUM ALLOY 6061 OVERALL
  • Thread Class: 2B ALL ENDS
  • Surface Treatment Document and Classification: MIL-A-8625,TYPE 2,CLASS 2 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL
  • Material: ALUMINUM ALLOY 6061 OVERALL
Applications
  • Applications requiring Aluminum Alloy 6061 Overall construction
General Description

The Tee,boss, cataloged under National Stock Number 4730-00-201-9591, 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 Rockwell Collins Inc. Government technical data includes 20 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 4 commercial cross-references from 3 manufacturers, enabling identification through both NSN and commercial part number lookups. 11 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Cancelled.

Technical Specifications
ParameterValue
NSN4730-00-201-9591
Primary Part Number21738-3
Item NameTee,boss
FSC / FSG4730 / 47 — No Item Name Available
ManufacturerRockwell Collins Inc
StatusCANCELLED
Material Document and ClassificationQQ-A-225/8,T651 FED SPEC SINGLE MATERIAL RESPONSE OVERALL
Connection TypeTHREADED INTERNAL BOSS ALL ENDS
Leg Length0.683 INCHES NOMINAL SECOND END IN
MaterialALUMINUM ALLOY 6061 OVERALL
Thread Class2B ALL ENDS
Surface Treatment Document and ClassificationMIL-A-8625,TYPE 2,CLASS 2 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL
MaterialALUMINUM ALLOY 6061 OVERALL
Surface TreatmentANODIZE OVERALL
Thread Series DesignatorUNF ALL ENDS
Nominal Thread Size0.250 INCHES ALL ENDS IN
Material Document and ClassificationQQ-A-225/8,T651 FED SPEC SINGLE MATERIAL RESPONSE OVERALL
Surface Treatment Document and ClassificationMIL-A-8625,TYPE 2,CLASS 2 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL
Connection StyleGASKET SEAL (BOSS) ALL ENDS
Media for Which DesignedFLUID SINGLE RESPONSE
Nominal Thread Size0.250 INCHES ALL ENDS IN
Media for Which DesignedFLUID SINGLE RESPONSE
Leg Length0.967 INCHES NOMINAL FIRST END IN
Surface TreatmentANODIZE OVERALL
Thread Series DesignatorUNF ALL ENDS
Leg Length0.863 INCHES MINIMUM AND 0.873 INCHES MAXIMUM THIRD END IN
Lifecycle & Compliance
Acquisition StatusCANCELLED
HAZMATNo
Verified Substitutes 11
5895-00-051-475821738 INTERCHANGEABLE
Duplexer
L3 Technologies, Inc. Div Communication Systems-East
5930-00-091-9254203974-1 INTERCHANGEABLE
Switch,thermostatic
Honeywell International Inc. Div Aerospace - Torrance
4320-00-116-3636Y501830208 INTERCHANGEABLE
Governor,pump,pressure Regulatin
Leslie Controls, Inc. Dba Leslie Controls Inc
3040-00-163-108099121738 INTERCHANGEABLE
Lever,manual Control
Alfa Laval Inc
5325-00-174-985510SA0227 INTERCHANGEABLE
Ring,retaining
Volvo Trucks North America, Inc. Dba (foreign Parent Is Volvo Lastvagnar Ab, Goteborg, Sweden.)
4330-00-212-722531A8188 INTERCHANGEABLE
Cleaner Element
Magnetic Technologies Corp Div Ogallala Electronics Division
4310-01-073-551221738 INTERCHANGEABLE
Rod and Piston Asse
American Bristol Industries Inc.
4730-01-170-531921738-3 INTERCHANGEABLE
Tee,boss
Rockwell Collins Inc
5340-01-252-334521738 INTERCHANGEABLE
Plate,mounting
Parker Hannifin Corporation Div Hydraulic Systems Division
3040-01-478-09463522879 INTERCHANGEABLE
Shaft,shouldered
Cummins Inc.
Cross-Reference Index
Part NumberManufacturer
A51K9035-1 Northrop Grumman Systems Corporation (USA)
21738 Rockwell Collins Inc (USA)
A51K9035-1 Northrop Grumman Systems Corporation Dba Northrop Grumman Systems Corp Div Northrop Grumman Aeronautics Systems (USA)
21738-3 PRIMARY Rockwell Collins Inc (USA)
Related Parts
5895-00-051-4758INTERCHANGEABLE
DUPLEXER
21738
5930-00-091-9254INTERCHANGEABLE
SWITCH,THERMOSTATIC
203974-1
4320-00-116-3636INTERCHANGEABLE
GOVERNOR,PUMP,PRESSURE REGULATIN
Y501830208
3040-00-163-1080INTERCHANGEABLE
LEVER,MANUAL CONTROL
99121738
5325-00-174-9855INTERCHANGEABLE
RING,RETAINING
10SA0227
4330-00-212-7225INTERCHANGEABLE
CLEANER ELEMENT
31A8188
4310-01-073-5512INTERCHANGEABLE
ROD AND PISTON ASSE
21738
4730-01-170-5319INTERCHANGEABLE
TEE,BOSS
21738-3
5340-01-252-3345INTERCHANGEABLE
PLATE,MOUNTING
21738
3040-01-478-0946INTERCHANGEABLE
SHAFT,SHOULDERED
3522879
7010-01-616-6516INTERCHANGEABLE
UAC-IS MEYER RANGE
217383

Frequently Asked Questions

What is NSN 4730-00-201-9591?

NSN 4730-00-201-9591 is a Tee,boss, manufactured by Rockwell Collins Inc, classified under FSC 4730 (No Item Name Available). Status: cancelled.

What are the part numbers for NSN 4730-00-201-9591?

NSN 4730-00-201-9591 has 4 cross-referenced part numbers: A51K9035-1 (Northrop Grumman Systems Corporation), 21738 (Rockwell Collins Inc), A51K9035-1 (Northrop Grumman Systems Corporation Dba Northrop Grumman Systems Corp Div Northrop Grumman Aeronautics Systems), 21738-3 (Rockwell Collins Inc).

What NSN replaces 4730-00-201-9591?

There are 11 known substitutes for 4730-00-201-9591: 5895-00-051-4758, 5930-00-091-9254, 4320-00-116-3636 and 8 more. Verify interchangeability with system specifications before substitution.

What are the specifications of 21738-3?

Key specifications for 21738-3: Material Document and Classification: QQ-A-225/8,T651 FED SPEC SINGLE MATERIAL RESPONSE OVERALL; Connection Type: THREADED INTERNAL BOSS ALL ENDS; Leg Length: 0.683 INCHES NOMINAL SECOND END IN; Material: ALUMINUM ALLOY 6061 OVERALL. 22 total characteristics are documented in the Federal Logistics Information System.

Is NSN 4730-00-201-9591 still in active supply?

NSN 4730-00-201-9591 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.
PartsTable Design LLC · partstable.com