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831749-403 — COUPLING,BOSS

✓ Government record, cited
— · HOSE FITTING
PRODUCT OVERVIEW

831749-403: COUPLING,BOSS.

The COUPLING,BOSS is a the manufacturer industrial component. Key specifications include thread_class: 3A ALL ENDS A, connection_type: THREADED EXTERNAL BOSS ALL ENDS, connection_style: FLARED W/ GASKET SEAL (BOSS) ALL ENDS, special_features: U/O CREW ESCAPE OF B1B ACFT, style_designator: PLAIN, nominal_thread_size: 0.4375 INCHES ALL ENDS IN. This part is cataloged in the U.S.

Government catalog under NSN 4730-01-233-2108, indicating validated use in U.S. government and defense logistics supply chains. Available through authorized enterprise resellers and TPM (Third Party Maintenance) channels.

Verify compatibility with your specific system configuration before ordering.

WHERE IT FITS
831749-403
NSN: 4730-01-233-2108
FSC: 4730 — Hose, Pipe, Tube, Lubrication, and Railing Fittings
CAGE: 92824 — MAG AEROSPACE INDUSTRIES INC.,DBA MONOGRAMSYSTEMS DBA MONOGRAM SYSTEMS (USA)
SPECIFICATIONS
thread_class3A ALL ENDS A
connection_typeTHREADED EXTERNAL BOSS ALL ENDS
connection_styleFLARED W/ GASKET SEAL (BOSS) ALL ENDS
special_featuresU/O CREW ESCAPE OF B1B ACFT
style_designatorPLAIN
nominal_thread_size0.4375 INCHES ALL ENDS IN
nominal_overall_length3.487 INCHES IN
thread_series_designatorUNIFIED NATIONAL JOINT FINE (UNJF) ALL ENDS
NSN4730-01-233-2108
COMPONENT DIAGRAM
HOSE FITTING — THREAD TYPE IS CRITICAL END A: — STRAIGHT END B: — SPECIFICATIONS Thread: — Material: — Pressure: — PN: 831749-403 · OEM ⚠ VERIFY BEFORE ORDERING NPT ≠ BSPT — tapered threads look identical but are NOT interchangeable. Wrong thread = leak. JIC (37°) ≠ AN (37°) ≠ SAE 45° — flare angles must match exactly. Measure thread pitch with gauge — visual identification is unreliable ✓ BROKER TIP Always use thread sealant (PTFE tape or pipe compound) on tapered threads (NPT/BSPT). JIC/AN flare fittings seal metal-to-metal — never use tape on flare connections PARTSTABLE TECHNICAL DRAWING — NOT TO SCALE
KEY FEATURES
•
CONNECTION STYLE: FLARED W/ GASKET SEAL (BOSS) ALL ENDS
•
NOMINAL OVERALL LENGTH: 3.487 INCHES IN
•
CONNECTION TYPE: THREADED EXTERNAL BOSS ALL ENDS
•
STYLE DESIGNATOR: PLAIN
•
NOMINAL THREAD SIZE: 0.4375 INCHES ALL ENDS IN
•
THREAD CLASS: 3A ALL ENDS A
•
THREAD SERIES DESIGNATOR: UNIFIED NATIONAL JOINT FINE (UNJF) ALL ENDS
TECHNICAL CHARACTERISTICS
CONNECTION STYLEFLARED W/ GASKET SEAL (BOSS) ALL ENDS
NOMINAL OVERALL LENGTH3.487 INCHES IN
CONNECTION TYPETHREADED EXTERNAL BOSS ALL ENDS
STYLE DESIGNATORPLAIN
NOMINAL THREAD SIZE0.4375 INCHES ALL ENDS IN
SPECIAL FEATURESU/O CREW ESCAPE OF B1B ACFT
THREAD CLASS3A ALL ENDS A
THREAD SERIES DESIGNATORUNIFIED NATIONAL JOINT FINE (UNJF) ALL ENDS
OTHER ITEMS IN FSC 4730 — Hose, Pipe, Tube, Lubrication, and Railing Fittings
Items in the same Federal Supply class. No interchangeability or substitution relationship is implied.
4730-00-000-1895 4730-00-000-4289 4730-00-000-4445 4730-00-000-8373 4730-00-000-8897 4730-00-001-0007 4730-00-001-0008
SUBSTITUTES & CROSS-REFERENCES

No substitute or cross-reference records for this part.

LIFECYCLE
NSN statusActive· U.S. Government catalog
Acquisition advice: Normally procured from the manufacturer (OEM)Demilitarization required — critical (Q)
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FREQUENTLY ASKED QUESTIONS
What is 831749-403?
831749-403 is a COUPLING,BOSS.
What is the NSN for 831749-403?
831749-403 is cataloged in the U.S. Government catalog under NSN 4730-01-233-2108. This indicates validated use in U.S. government and defense supply chains.
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✓ PartsTable — the parts reference. Every fact cited to its source.
PartsTable Design LLC · partstable.com
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.
PartsTable commercial catalog: edition Unified commercial catalog snapshot through 2026-09-28, edition date not on file, retrieved 2026-09-28.