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MS21902-2 — UNION,TUBE

✓ Government record, cited
— · HOSE FITTING
PRODUCT OVERVIEW

MS21902-2: UNION,TUBE.

The UNION,TUBE is a the manufacturer industrial component. Key specifications include material: STEEL COMP 1137 OR STEEL COMP 1141 OVERALL, thread_class: 3A ALL ENDS A, connection_type: THREADED EXTERNAL BOSS ALL ENDS, connection_style: EXTERNAL SEAT FOR GASKET SEAL (BOSS) ALL ENDS, style_designator: FLARELESS W/ CENTER WRENCHING FACILITY, surface_treatment: CADMIUM AND CHROMATE OVERALL. This part is cataloged in the U.S.

Government catalog under NSN 4730-00-203-7490, 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
MS21902-2
NSN: 4730-00-203-7490
FSC: 4730 — Hose, Pipe, Tube, Lubrication, and Railing Fittings
CAGE: 0U583 — SAE INTERNATIONAL DBA SAE INTERNATIONAL (USA)
SPECIFICATIONS
materialSTEEL COMP 1137 OR STEEL COMP 1141 OVERALL
thread_class3A ALL ENDS A
connection_typeTHREADED EXTERNAL BOSS ALL ENDS
connection_styleEXTERNAL SEAT FOR GASKET SEAL (BOSS) ALL ENDS
style_designatorFLARELESS W/ CENTER WRENCHING FACILITY
surface_treatmentCADMIUM AND CHROMATE OVERALL
nominal_thread_size0.312 INCHES ALL ENDS IN
maximum_operating_temp225.0 FAHRENHEIT FIRST RESPONSE DEGF
nominal_overall_length1.062 INCHES IN
end_item_identification2350-01-031-8851
media_for_which_designedOXYGEN, GASEOUS THIRD RESPONSE
thread_series_designatorUNIFIED NATIONAL JOINT FINE (UNJF) ALL ENDS
NSN4730-00-203-7490
COMPONENT DIAGRAM
HOSE FITTING — THREAD TYPE IS CRITICAL END A: — STRAIGHT END B: — SPECIFICATIONS Thread: — Material: — Pressure: — PN: MS21902-2 · 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
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: QQ-P-416,TY 2,CL 1 FED SPEC 1ST TREATMENT RESPONSE OVERALL
•
CONNECTION STYLE: EXTERNAL SEAT FOR GASKET SEAL (BOSS) ALL ENDS
•
NOMINAL OVERALL LENGTH: 1.062 INCHES IN
•
CONNECTION TYPE: THREADED EXTERNAL BOSS ALL ENDS
•
STYLE DESIGNATOR: FLARELESS W/ CENTER WRENCHING FACILITY
•
MATERIAL DOCUMENT AND CLASSIFICATION: 66,AISI/SAE 1137 OR 1141 FED STD SINGLE MATERIAL RESPONSE OVERALL
•
REDUCED PASSAGE NOMINAL INSIDE DIAMETER: 0.062 INCHES ALL ENDS IN
•
NOMINAL THREAD SIZE: 0.312 INCHES ALL ENDS IN
TECHNICAL CHARACTERISTICS
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONQQ-P-416,TY 2,CL 1 FED SPEC 1ST TREATMENT RESPONSE OVERALL
CONNECTION STYLEEXTERNAL SEAT FOR GASKET SEAL (BOSS) ALL ENDS
NOMINAL OVERALL LENGTH1.062 INCHES IN
CONNECTION TYPETHREADED EXTERNAL BOSS ALL ENDS
STYLE DESIGNATORFLARELESS W/ CENTER WRENCHING FACILITY
MATERIAL DOCUMENT AND CLASSIFICATION66,AISI/SAE 1137 OR 1141 FED STD SINGLE MATERIAL RESPONSE OVERALL
REDUCED PASSAGE NOMINAL INSIDE DIAMETER0.062 INCHES ALL ENDS IN
NOMINAL THREAD SIZE0.312 INCHES ALL ENDS IN
SPECIFICATION/STANDARD DATA96906-MS21902 GOVERNMENT STANDARD
MAXIMUM OPERATING TEMP225.0 FAHRENHEIT FIRST RESPONSE DEGF
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
SAE-AS18280Reference document
Same NSN cross-reference
Reference document — Design control — primary reference
LIFECYCLE
NSN statusActive· U.S. Government catalog
Acquisition advice: Terminal item — stock exhausted; no further procurementNo demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is MS21902-2?
MS21902-2 is a UNION,TUBE.
What parts can replace MS21902-2?
There is 1 known substitute for MS21902-2: SAE-AS18280. Substitute compatibility should be verified for your specific system.
What is the NSN for MS21902-2?
MS21902-2 is cataloged in the U.S. Government catalog under NSN 4730-00-203-7490. This indicates validated use in U.S. government and defense supply chains.
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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.