PartsTable
Technical Data Sheet
Download PDF

ST2121-04 — NUT,TUBE COUPLING

✓ Government record, cited
— · HOSE FITTING
PRODUCT OVERVIEW

ST2121-04: NUT,TUBE COUPLING.

The NUT,TUBE COUPLING is a the manufacturer industrial component. Key specifications include end_item_identification: KC-46 AIRCRAFT, reference_number_differentiating_characteristics: ITEM IS FAA CERTIFIED. This part is cataloged in the U.S.

Government catalog under NSN 4730-00-367-8100, 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
ST2121-04
NSN: 4730-00-367-8100
NIINs: 003678100, 016694777
FSC: 4730 — Hose, Pipe, Tube, Lubrication, and Railing Fittings
CAGE: 77445 — RTX CORPORATION DBA PRATT & WHITNEY DIV PRATT &WHITNEY (USA)
SPECIFICATIONS
end_item_identificationKC-46 AIRCRAFT
reference_number_differentiating_characteristicsITEM IS FAA CERTIFIED
NSN4730-00-367-8100
COMPONENT DIAGRAM
HOSE FITTING — THREAD TYPE IS CRITICAL END A: — STRAIGHT END B: — SPECIFICATIONS Thread: — Material: — Pressure: — PN: ST2121-04 · 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: 0.553 INCHES MINIMUM AND 0.564 INCHES MAXIMUM IN
•
THREAD SERIES: UNIFIED NATIONAL JOINT FINE (UNJF)
•
HOLE CONFIGURATION STYLE: CONFIGURATION B
•
MATERIAL DOCUMENT AND CLASSIFICATION: AMS5646 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
•
THREAD DIRECTION: RIGHT-HAND
•
NOMINAL THREAD SIZE: 0.438 INCHES IN
•
NUT HEIGHT: 0.600 INCHES MINIMUM AND 0.620 INCHES MAXIMUM IN
•
DRILLED HOLE DIAMETER: 0.057 INCHES MINIMUM AND 0.062 INCHES MAXIMUM IN
TECHNICAL CHARACTERISTICS
WIDTH ACROSS FLATS0.553 INCHES MINIMUM AND 0.564 INCHES MAXIMUM IN
THREAD SERIESUNIFIED NATIONAL JOINT FINE (UNJF)
HOLE CONFIGURATION STYLECONFIGURATION B
MATERIAL DOCUMENT AND CLASSIFICATIONAMS5646 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
THREAD DIRECTIONRIGHT-HAND
NOMINAL THREAD SIZE0.438 INCHES IN
NUT HEIGHT0.600 INCHES MINIMUM AND 0.620 INCHES MAXIMUM IN
DRILLED HOLE DIAMETER0.057 INCHES MINIMUM AND 0.062 INCHES MAXIMUM IN
NUT STYLETUBE COUPLING
THREAD CLASS3B
SUBSTITUTES & CROSS-REFERENCES 1
4730PL0741555Reference document
Same NSN cross-reference
Reference document — Informative reference only
LIFECYCLE
NSN statusActive· U.S. Government catalog
Acquisition advice: Normally procured from the manufacturer (OEM)No demilitarization required
Ready to buy ST2121-04?
Compare prices from verified sellers on eBay
Buy on eBay →
As an eBay Partner, PartsTable may earn a commission. Your price is not affected.
FREQUENTLY ASKED QUESTIONS
What is ST2121-04?
ST2121-04 is a NUT,TUBE COUPLING.
What parts can replace ST2121-04?
There is 1 known substitute for ST2121-04: 4730PL0741555. Substitute compatibility should be verified for your specific system.
What is the NSN for ST2121-04?
ST2121-04 is cataloged in the U.S. Government catalog under NSN 4730-00-367-8100. This indicates validated use in U.S. government and defense supply chains.
Community Feedback
Leave a Comment
Comments are reviewed before appearing. You will receive an email to verify before your comment appears.

Request a Quote — ST2121-04

✓ 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.