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NAS591-6H — INVERTED NUT,TUBE COUPLING

✓ Government record, cited
— · HOSE FITTING
PRODUCT OVERVIEW

NAS591-6H: INVERTED NUT,TUBE COUPLING.

The INVERTED NUT,TUBE COUPLING is a the manufacturer industrial component. Key specifications include material: ALUMINUM ALLOY 2024, thread_size: 9/16-18, thread_class: 3A A, overall_length: 0.490 INCHES MINIMUM AND 0.510 INCHES MAXIMUM IN, special_features: W/THREE DRILLED SAFETY WIRE HOLES, style_designator: INVERTED NUT, TUBE, FLARE. This part is cataloged in the U.S.

Government catalog under NSN 4730-01-142-8181, 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
NAS591-6H
NSN: 4730-01-142-8181
FSC: 4730 — Hose, Pipe, Tube, Lubrication, and Railing Fittings
CAGE: 80205 — NATIONAL AEROSPACE STANDARDS COMMITTEE AEROSPACE INDUSTRIES ASSOCIATION OF AMERICA INC NOT FOR RFQ OR SOLICITATION USE (USA)
SPECIFICATIONS
materialALUMINUM ALLOY 2024
thread_size9/16-18
thread_class3A A
overall_length0.490 INCHES MINIMUM AND 0.510 INCHES MAXIMUM IN
special_featuresW/THREE DRILLED SAFETY WIRE HOLES
style_designatorINVERTED NUT, TUBE, FLARE
thread_directionRIGHT-HAND
seat_angle_in_deg33.0
surface_treatmentANODIZE
fabrication_methodBAR STOCK, MACHINED OR ROD STOCK, MACHINED
width_across_flats0.678 INCHES MINIMUM AND 0.698 INCHES MAXIMUM IN
casehardening_indicatorNOT CASEHARDENED
NSN4730-01-142-8181
COMPONENT DIAGRAM
HOSE FITTING — THREAD TYPE IS CRITICAL END A: — STRAIGHT END B: — SPECIFICATIONS Thread: — Material: — Pressure: — PN: NAS591-6H · 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
•
WIDTH ACROSS FLATS: 0.678 INCHES MINIMUM AND 0.698 INCHES MAXIMUM IN
•
SEAT ANGLE IN DEG: 33.0
•
TUBE OUTSIDE DIAMETER FOR WHICH DESIGNED: 0.375 INCHES NOMINAL IN
•
STYLE DESIGNATOR: INVERTED NUT, TUBE, FLARE
•
MATERIAL DOCUMENT AND CLASSIFICATION: QQ-A-225/6, ALLOY 2024, T851 FED SPEC SINGLE MATERIAL RESPONSE
•
THREAD DIRECTION: RIGHT-HAND
•
CASEHARDENING INDICATOR: NOT CASEHARDENED
TECHNICAL CHARACTERISTICS
WIDTH ACROSS FLATS0.678 INCHES MINIMUM AND 0.698 INCHES MAXIMUM IN
SEAT ANGLE IN DEG33.0
TUBE OUTSIDE DIAMETER FOR WHICH DESIGNED0.375 INCHES NOMINAL IN
STYLE DESIGNATORINVERTED NUT, TUBE, FLARE
MATERIAL DOCUMENT AND CLASSIFICATIONQQ-A-225/6, ALLOY 2024, T851 FED SPEC SINGLE MATERIAL RESPONSE
OVERALL LENGTH0.490 INCHES MINIMUM AND 0.510 INCHES MAXIMUM IN
THREAD DIRECTIONRIGHT-HAND
CASEHARDENING INDICATORNOT CASEHARDENED
THREAD SIZE9/16-18
SPECIAL FEATURESW/THREE DRILLED SAFETY WIRE HOLES
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 NAS591-6H?
NAS591-6H is a INVERTED NUT,TUBE COUPLING.
What is the NSN for NAS591-6H?
NAS591-6H is cataloged in the U.S. Government catalog under NSN 4730-01-142-8181. 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.