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3657-40D — NUT ASSEMBLY,TUBE COUPLING

✓ Government record, cited
— · HOSE FITTING
PRODUCT OVERVIEW

3657-40D: NUT ASSEMBLY,TUBE COUPLING.

The NUT ASSEMBLY,TUBE COUPLING is a the manufacturer industrial component. Key specifications include material: ALUMINUM ALLOY, thread_size: 3-12, thread_class: 2B, overall_length: 0.841 INCHES NOMINAL IN, outside_diameter: 3.145 INCHES NOMINAL IN, style_designator: NUT ASSEMBLY. This part is cataloged in the U.S.

Government catalog under NSN 4730-00-933-0899, 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
3657-40D
NSN: 4730-00-933-0899
FSC: 4730 — Hose, Pipe, Tube, Lubrication, and Railing Fittings
CAGE: 79326 — TRANSDIGM INC DIV ADELWIGGINS GROUP (USA)
SPECIFICATIONS
materialALUMINUM ALLOY
thread_size3-12
thread_class2B
overall_length0.841 INCHES NOMINAL IN
outside_diameter3.145 INCHES NOMINAL IN
style_designatorNUT ASSEMBLY
thread_directionRIGHT-HAND
surface_treatmentANODIZE
screw_thread_series_designatorUN
tube_outside_diameter_for_which_designed2.500 INCHES NOMINAL IN
NSN4730-00-933-0899
COMPONENT DIAGRAM
HOSE FITTING — THREAD TYPE IS CRITICAL END A: — STRAIGHT END B: — SPECIFICATIONS Thread: — Material: — Pressure: — PN: 3657-40D · 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
•
TUBE OUTSIDE DIAMETER FOR WHICH DESIGNED: 2.500 INCHES NOMINAL IN
•
STYLE DESIGNATOR: NUT ASSEMBLY
•
OUTSIDE DIAMETER: 3.145 INCHES NOMINAL IN
•
THREAD DIRECTION: RIGHT-HAND
•
THREAD SIZE: 3-12
•
SCREW THREAD SERIES DESIGNATOR: UN
•
SURFACE TREATMENT: ANODIZE
TECHNICAL CHARACTERISTICS
TUBE OUTSIDE DIAMETER FOR WHICH DESIGNED2.500 INCHES NOMINAL IN
STYLE DESIGNATORNUT ASSEMBLY
OVERALL LENGTH0.841 INCHES NOMINAL IN
OUTSIDE DIAMETER3.145 INCHES NOMINAL IN
THREAD DIRECTIONRIGHT-HAND
THREAD SIZE3-12
SCREW THREAD SERIES DESIGNATORUN
SURFACE TREATMENTANODIZE
THREAD CLASS2B
MATERIALALUMINUM 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
No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is 3657-40D?
3657-40D is a NUT ASSEMBLY,TUBE COUPLING.
What is the NSN for 3657-40D?
3657-40D is cataloged in the U.S. Government catalog under NSN 4730-00-933-0899. 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.