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SS318-4 — NUT,TUBE COUPLING

✓ Government record, cited
— · HOSE FITTING
PRODUCT OVERVIEW

SS318-4: NUT,TUBE COUPLING.

The NUT,TUBE COUPLING is a the manufacturer industrial component. Key specifications include material: STEEL CORROSION RESISTING OVERALL, thread_class: 2B, thread_series: UNF, thread_direction: RIGHT-HAND, nominal_thread_size: 0.438 INCHES IN, thread_quantity_per_inch: 20. This part is cataloged in the U.S.

Government catalog under NSN 4730-01-649-3593, 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
SS318-4
NSN: 4730-01-649-3593
FSC: 4730 — Hose, Pipe, Tube, Lubrication, and Railing Fittings
CAGE: 22031 — AIR-WAY MANUFACTURING COMPANY (USA)
SPECIFICATIONS
materialSTEEL CORROSION RESISTING OVERALL
thread_class2B
thread_seriesUNF
thread_directionRIGHT-HAND
nominal_thread_size0.438 INCHES IN
thread_quantity_per_inch20
nominal_tube_outside_diameter0.250 INCHES IN
part_name_assigned_by_controlling_agencyTUBE NUT
NSN4730-01-649-3593
COMPONENT DIAGRAM
HOSE FITTING — THREAD TYPE IS CRITICAL END A: — STRAIGHT END B: — SPECIFICATIONS Thread: — Material: — Pressure: — PN: SS318-4 · 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
•
THREAD SERIES: UNF
•
THREAD DIRECTION: RIGHT-HAND
•
NOMINAL THREAD SIZE: 0.438 INCHES IN
•
THREAD CLASS: 2B
•
THREAD QUANTITY PER INCH: 20
•
MATERIAL: STEEL CORROSION RESISTING OVERALL
•
NOMINAL TUBE OUTSIDE DIAMETER: 0.250 INCHES IN
TECHNICAL CHARACTERISTICS
THREAD SERIESUNF
THREAD DIRECTIONRIGHT-HAND
NOMINAL THREAD SIZE0.438 INCHES IN
PART NAME ASSIGNED BY CONTROLLING AGENCYTUBE NUT
THREAD CLASS2B
THREAD QUANTITY PER INCH20
MATERIALSTEEL CORROSION RESISTING OVERALL
NOMINAL TUBE OUTSIDE DIAMETER0.250 INCHES IN
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 SS318-4?
SS318-4 is a NUT,TUBE COUPLING.
What is the NSN for SS318-4?
SS318-4 is cataloged in the U.S. Government catalog under NSN 4730-01-649-3593. 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.