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MS21916D20-4 — REDUCER,BOSS

✓ Government record, cited
— · HOSE FITTING
PRODUCT OVERVIEW

MS21916D20-4: REDUCER,BOSS.

The REDUCER,BOSS is a the manufacturer industrial component. Key specifications include material: ALUMINUM ALLOY 2024 OVERALL, reducer_type: CONCENTRIC, thread_class: 3A ALL ENDS A, connection_type: THREADED EXTERNAL BOSS ALL ENDS, connection_style: EXTERNAL SEAT FOR GASKET SEAL (BOSS) ALL ENDS, surface_treatment: ANODIZE OVERALL. This part is cataloged in the U.S.

Government catalog under NSN 4730-00-555-8013, 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
MS21916D20-4
NSN: 4730-00-555-8013
FSC: 4730 — Hose, Pipe, Tube, Lubrication, and Railing Fittings
CAGE: 0U583 — SAE INTERNATIONAL DBA SAE INTERNATIONAL (USA)
SPECIFICATIONS
materialALUMINUM ALLOY 2024 OVERALL
reducer_typeCONCENTRIC
thread_class3A ALL ENDS A
connection_typeTHREADED EXTERNAL BOSS ALL ENDS
connection_styleEXTERNAL SEAT FOR GASKET SEAL (BOSS) ALL ENDS
surface_treatmentANODIZE OVERALL
nominal_thread_size1.625 INCHES FIRST END IN
nominal_overall_length1.531 INCHES IN
end_item_identificationAIRCRAFT FLUID SYSTEMS
thread_quantity_per_inch12 FIRST END
thread_series_designatorUNIFIED NATIONAL JOINT (UNJ) FIRST END
specification/standard_data96906-MS21916 GOVERNMENT STANDARD
NSN4730-00-555-8013
COMPONENT DIAGRAM
HOSE FITTING — THREAD TYPE IS CRITICAL END A: — STRAIGHT END B: — SPECIFICATIONS Thread: — Material: — Pressure: — PN: MS21916D20-4 · 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
•
CONNECTION STYLE: EXTERNAL SEAT FOR GASKET SEAL (BOSS) ALL ENDS
•
NOMINAL OVERALL LENGTH: 1.531 INCHES IN
•
CONNECTION TYPE: THREADED EXTERNAL BOSS ALL ENDS
•
MATERIAL DOCUMENT AND CLASSIFICATION: QQ-A-225/6,T6 FED SPEC SINGLE MATERIAL RESPONSE OVERALL
•
NOMINAL THREAD SIZE: 1.625 INCHES FIRST END IN
•
SPECIFICATION/STANDARD DATA: 96906-MS21916 GOVERNMENT STANDARD
•
SURFACE TREATMENT: ANODIZE OVERALL
TECHNICAL CHARACTERISTICS
CONNECTION STYLEEXTERNAL SEAT FOR GASKET SEAL (BOSS) ALL ENDS
NOMINAL OVERALL LENGTH1.531 INCHES IN
CONNECTION TYPETHREADED EXTERNAL BOSS ALL ENDS
MATERIAL DOCUMENT AND CLASSIFICATIONQQ-A-225/6,T6 FED SPEC SINGLE MATERIAL RESPONSE OVERALL
NOMINAL THREAD SIZE1.625 INCHES FIRST END IN
NOMINAL THREAD SIZE0.438 INCHES SECOND END IN
SPECIFICATION/STANDARD DATA96906-MS21916 GOVERNMENT STANDARD
SURFACE TREATMENTANODIZE OVERALL
THREAD CLASS3A ALL ENDS A
END ITEM IDENTIFICATIONAIRCRAFT FLUID SYSTEMS
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: Normally procured from the manufacturer (OEM)No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is MS21916D20-4?
MS21916D20-4 is a REDUCER,BOSS.
What parts can replace MS21916D20-4?
There is 1 known substitute for MS21916D20-4: SAE-AS18280. Substitute compatibility should be verified for your specific system.
What is the NSN for MS21916D20-4?
MS21916D20-4 is cataloged in the U.S. Government catalog under NSN 4730-00-555-8013. 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.