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3178205-4 — TAILPIECE,UNION

✓ Government record, cited
— · HOSE FITTING
PRODUCT OVERVIEW

3178205-4: TAILPIECE,UNION.

The TAILPIECE,UNION is a the manufacturer industrial component. Key specifications include material: COPPER ALLOY, seat_type: STRAIGHT FACE, overall_length: 0.438 INCHES NOMINAL IN, end_connection_type: BRAZED, union_outside_diameter: 0.531 INCHES NOMINAL IN, tubing_outside_diameter: 0.375 INCHES NOMINAL IN. This part is cataloged in the U.S.

Government catalog under NSN 4730-01-057-8745, 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
3178205-4
NSN: 4730-01-057-8745
FSC: 4730 — Hose, Pipe, Tube, Lubrication, and Railing Fittings
CAGE: 10001 — NAVAIR AND NAVSEA MANAGED ORIGINAL DESIGN ACTIVITY DWG NOT MATERIAL/PARTS SUPPLIER (USA)
SPECIFICATIONS
materialCOPPER ALLOY
seat_typeSTRAIGHT FACE
overall_length0.438 INCHES NOMINAL IN
end_connection_typeBRAZED
union_outside_diameter0.531 INCHES NOMINAL IN
tubing_outside_diameter0.375 INCHES NOMINAL IN
NSN4730-01-057-8745
COMPONENT DIAGRAM
HOSE FITTING — THREAD TYPE IS CRITICAL END A: — STRAIGHT END B: — SPECIFICATIONS Thread: — Material: — Pressure: — PN: 3178205-4 · 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
•
UNION OUTSIDE DIAMETER: 0.531 INCHES NOMINAL IN
•
END CONNECTION TYPE: BRAZED
•
SEAT TYPE: STRAIGHT FACE
•
TUBING OUTSIDE DIAMETER: 0.375 INCHES NOMINAL IN
•
MATERIAL: COPPER ALLOY
TECHNICAL CHARACTERISTICS
UNION OUTSIDE DIAMETER0.531 INCHES NOMINAL IN
END CONNECTION TYPEBRAZED
OVERALL LENGTH0.438 INCHES NOMINAL IN
SEAT TYPESTRAIGHT FACE
TUBING OUTSIDE DIAMETER0.375 INCHES NOMINAL IN
MATERIALCOPPER ALLOY
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)No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is 3178205-4?
3178205-4 is a TAILPIECE,UNION.
What is the NSN for 3178205-4?
3178205-4 is cataloged in the U.S. Government catalog under NSN 4730-01-057-8745. 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.