PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

STD176Nut,tube Coupling

Textron Lycoming Inc Williamsport Plant · NSN 4730-00-278-5453 · FSC 4730 · No Item Name Available
Verified by PartsTable
NSN 4730-00-278-5453 — this item is cataloged by the U.S. Government under National Stock Number 4730-00-278-5453. Primary manufacturer part number: STD176.
Features
  • Nut,tube Coupling — FSC 4730
  • Thread Class: 3B
  • Material: COPPER ALLOY OVERALL
  • Nominal Thread Size: 0.312 INCHES IN
  • Width Across Flats: 0.371 INCHES MINIMUM AND 0.378 INCHES MAXIMUM IN
  • Thread Series: UNEF
  • Smallest Inside Diameter: 0.173 INCHES MINIMUM AND 0.177 INCHES MAXIMUM IN
  • Nut Style: TUBE COUPLING
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 4730-00-278-5453, 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 Textron Lycoming Inc Williamsport Plant. Government technical data includes 12 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 10 commercial cross-references from 7 manufacturers, enabling identification through both NSN and commercial part number lookups. 12 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Cancelled.

Technical Specifications
ParameterValue
NSN4730-00-278-5453
Primary Part NumberSTD176
Item NameNut,tube Coupling
FSC / FSG4730 / 47 — No Item Name Available
ManufacturerTextron Lycoming Inc Williamsport Plant
StatusCANCELLED
Thread Class3B
MaterialCOPPER ALLOY OVERALL
Nominal Thread Size0.312 INCHES IN
Width Across Flats0.371 INCHES MINIMUM AND 0.378 INCHES MAXIMUM IN
Thread SeriesUNEF
Smallest Inside Diameter0.173 INCHES MINIMUM AND 0.177 INCHES MAXIMUM IN
Nut StyleTUBE COUPLING
Thread Quantity Per Inch32
Nominal Tube Outside Diameter0.125 INCHES IN
Thread DirectionRIGHT-HAND
Length to Shoulder0.281 INCHES NOMINAL IN
Nut Height0.423 INCHES MINIMUM AND 0.453 INCHES MAXIMUM IN
Lifecycle & Compliance
Acquisition StatusCANCELLED
HAZMATNo
Verified Substitutes 12
2910-00-123-0078S9394-2 INTERCHANGEABLE
Carburetor,float
Lincoln Electric Holdings Inc
4730-00-203-4681 INTERCHANGEABLE
Adapter,straight,pipe to Tube
4730-00-277-6403 INTERCHANGEABLE
Adapter,straight,pipe to Tube
4730-00-278-0830 INTERCHANGEABLE
Ferrule,brazing,tube Fitting
4730-00-278-083274962 INTERCHANGEABLE
Ferrule,brazing,tube Fitting
Pratt & Whitney Canada Corp Div Pratt & Whitney Canada Corp.
4730-00-278-0833 INTERCHANGEABLE
Ferrule,brazing,tube Fitting
4730-00-278-0837 INTERCHANGEABLE
Ferrule,brazing,tube Fitting
4730-00-278-5449 INTERCHANGEABLE
Nut,tube Coupling
4730-00-287-1128 INTERCHANGEABLE
Adapter,straight,pipe to Tube
4730-00-287-1130 INTERCHANGEABLE
Adapter,straight,pipe to Tube
Cross-Reference Index
Part NumberManufacturer
STD176 Textron Lycoming Inc Williamsport Plant (USA)
AN805-2 Power Industries Inc (USA)
AN805-2 Textron Lycoming Inc Williamsport Plant (USA)
MIL-F-6001 Military Standards Promulgated by Military Departments Under Authority of Defense Standardization Manual 4120 3-M
MIL-DTL-6001 Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M
AN805-2 Aeronautical Standards Group Dept of Navy and Air Force (USA)
5165169 U S Army Tank Automotive Command Amsta-Im-Mm (USA)
AN805-2 Franklin Engine Co Inc (USA)
12890 Franklin Engine Co Inc (USA)
0589 Power Industries Inc (USA)
Related Parts
2910-00-123-0078INTERCHANGEABLE
CARBURETOR,FLOAT
S9394-2
4730-00-203-4681INTERCHANGEABLE
ADAPTER,STRAIGHT,PIPE TO TUBE
4730-00-277-6403INTERCHANGEABLE
ADAPTER,STRAIGHT,PIPE TO TUBE
4730-00-278-0830INTERCHANGEABLE
FERRULE,BRAZING,TUBE FITTING
4730-00-278-0832INTERCHANGEABLE
FERRULE,BRAZING,TUBE FITTING
74962
4730-00-278-0833INTERCHANGEABLE
FERRULE,BRAZING,TUBE FITTING
4730-00-278-0837INTERCHANGEABLE
FERRULE,BRAZING,TUBE FITTING
4730-00-278-5449INTERCHANGEABLE
NUT,TUBE COUPLING
4730-00-287-1128INTERCHANGEABLE
ADAPTER,STRAIGHT,PIPE TO TUBE
4730-00-287-1130INTERCHANGEABLE
ADAPTER,STRAIGHT,PIPE TO TUBE
4730-00-287-1131INTERCHANGEABLE
ADAPTER,STRAIGHT,PIPE TO TUBE
4730-00-287-1132INTERCHANGEABLE
ADAPTER,STRAIGHT,PIPE TO TUBE

Frequently Asked Questions

What is NSN 4730-00-278-5453?

NSN 4730-00-278-5453 is a Nut,tube Coupling, manufactured by Textron Lycoming Inc Williamsport Plant, classified under FSC 4730 (No Item Name Available). Status: cancelled.

What are the part numbers for NSN 4730-00-278-5453?

NSN 4730-00-278-5453 has 10 cross-referenced part numbers: STD176 (Textron Lycoming Inc Williamsport Plant), AN805-2 (Power Industries Inc), AN805-2 (Textron Lycoming Inc Williamsport Plant), MIL-F-6001 (Military Standards Promulgated by Military Departments Under Authority of Defense Standardization Manual 4120 3-M), MIL-DTL-6001 (Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M) and 5 more.

What NSN replaces 4730-00-278-5453?

There are 12 known substitutes for 4730-00-278-5453: 2910-00-123-0078, 4730-00-203-4681, 4730-00-277-6403 and 9 more. Verify interchangeability with system specifications before substitution.

What are the specifications of STD176?

Key specifications for STD176: Thread Class: 3B; Material: COPPER ALLOY OVERALL; Nominal Thread Size: 0.312 INCHES IN; Width Across Flats: 0.371 INCHES MINIMUM AND 0.378 INCHES MAXIMUM IN. 12 total characteristics are documented in the Federal Logistics Information System.

Is NSN 4730-00-278-5453 still in active supply?

NSN 4730-00-278-5453 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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