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NAS594-20 — INVERTED NUT,TUBE COUPLING

✓ Government record, cited
— · HOSE FITTING
PRODUCT OVERVIEW

NAS594-20: INVERTED NUT,TUBE COUPLING.

The INVERTED NUT,TUBE COUPLING is a the manufacturer industrial component. Key specifications include material: STEEL COMP 431, thread_size: 1.625-12, thread_class: 3A A, overall_length: 0.844 INCHES NOMINAL IN, strength_rating: ERR-060, style_designator: INVERTED NUT, TUBE, FLARE. This part is cataloged in the U.S.

Government catalog under NSN 4730-00-540-6300, 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
NAS594-20
NSN: 4730-00-540-6300
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
materialSTEEL COMP 431
thread_size1.625-12
thread_class3A A
overall_length0.844 INCHES NOMINAL IN
strength_ratingERR-060
style_designatorINVERTED NUT, TUBE, FLARE
thread_directionRIGHT-HAND
seat_angle_in_deg33.0
surface_treatmentPASSIVATE
fabrication_methodBAR STOCK, MACHINED
width_across_flats1.375 INCHES NOMINAL IN
casehardening_indicatorNOT CASEHARDENED
NSN4730-00-540-6300
COMPONENT DIAGRAM
HOSE FITTING — THREAD TYPE IS CRITICAL END A: — STRAIGHT END B: — SPECIFICATIONS Thread: — Material: — Pressure: — PN: NAS594-20 · 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: 1.375 INCHES NOMINAL IN
•
MATERIAL HARDNESS RATING: 20.0 ROCKWELL C MINIMUM AND 32.0 ROCKWELL C MAXIMUM
•
SEAT ANGLE IN DEG: 33.0
•
STRENGTH RATING: ERR-060
•
TUBE OUTSIDE DIAMETER FOR WHICH DESIGNED: 1.250 INCHES NOMINAL IN
•
STYLE DESIGNATOR: INVERTED NUT, TUBE, FLARE
•
MATERIAL DOCUMENT AND CLASSIFICATION: MIL-S-18732, COND HT-200 MIL SPEC SINGLE MATERIAL RESPONSE
TECHNICAL CHARACTERISTICS
WIDTH ACROSS FLATS1.375 INCHES NOMINAL IN
MATERIAL HARDNESS RATING20.0 ROCKWELL C MINIMUM AND 32.0 ROCKWELL C MAXIMUM
SEAT ANGLE IN DEG33.0
STRENGTH RATINGERR-060
TUBE OUTSIDE DIAMETER FOR WHICH DESIGNED1.250 INCHES NOMINAL IN
STYLE DESIGNATORINVERTED NUT, TUBE, FLARE
MATERIAL DOCUMENT AND CLASSIFICATIONMIL-S-18732, COND HT-200 MIL SPEC SINGLE MATERIAL RESPONSE
OVERALL LENGTH0.844 INCHES NOMINAL IN
THREAD DIRECTIONRIGHT-HAND
CASEHARDENING INDICATORNOT CASEHARDENED
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 1
NAS597Reference document
Same NSN cross-reference
Reference document — Design control — primary reference
LIFECYCLE
NSN statusActive· U.S. Government catalog
Acquisition advice: Insurance item — stocked against contingency demandNo demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is NAS594-20?
NAS594-20 is a INVERTED NUT,TUBE COUPLING.
What parts can replace NAS594-20?
There is 1 known substitute for NAS594-20: NAS597. Substitute compatibility should be verified for your specific system.
What is the NSN for NAS594-20?
NAS594-20 is cataloged in the U.S. Government catalog under NSN 4730-00-540-6300. 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.