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MS21916-4-2R — REDUCER,BOSS

✓ Government record, cited
— · HOSE FITTING
PRODUCT OVERVIEW

MS21916-4-2R: REDUCER,BOSS.

The REDUCER,BOSS is a the manufacturer industrial component. Key specifications include material: STEEL COMP 321 OVERALL, thread_class: 3A ALL ENDS A, connection_type: THREADED EXTERNAL BOSS ALL ENDS, connection_style: EXTERNAL SEAT FOR GASKET SEAL (BOSS) ALL ENDS, nominal_thread_size: 0.4375 INCHES FIRST END IN, nominal_overall_length: 1.094 INCHES IN. This part is cataloged in the U.S.

Government catalog under NSN 4730-01-693-0283, 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
MS21916-4-2R
NSN: 4730-01-693-0283
FSC: 4730 — Hose, Pipe, Tube, Lubrication, and Railing Fittings
CAGE: 0U583 — SAE INTERNATIONAL DBA SAE INTERNATIONAL (USA)
SPECIFICATIONS
materialSTEEL COMP 321 OVERALL
thread_class3A ALL ENDS A
connection_typeTHREADED EXTERNAL BOSS ALL ENDS
connection_styleEXTERNAL SEAT FOR GASKET SEAL (BOSS) ALL ENDS
nominal_thread_size0.4375 INCHES FIRST END IN
nominal_overall_length1.094 INCHES IN
thread_quantity_per_inch20 FIRST END
thread_series_designatorUNIFIED NATIONAL JOINT FINE (UNJF) ALL ENDS
NSN4730-01-693-0283
COMPONENT DIAGRAM
HOSE FITTING — THREAD TYPE IS CRITICAL END A: — STRAIGHT END B: — SPECIFICATIONS Thread: — Material: — Pressure: — PN: MS21916-4-2R · 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: 1.094 INCHES IN
•
CONNECTION TYPE: THREADED EXTERNAL BOSS ALL ENDS
•
NOMINAL THREAD SIZE: 0.4375 INCHES FIRST END IN
•
THREAD CLASS: 3A ALL ENDS A
•
THREAD QUANTITY PER INCH: 24 SECOND END
TECHNICAL CHARACTERISTICS
CONNECTION STYLEEXTERNAL SEAT FOR GASKET SEAL (BOSS) ALL ENDS
NOMINAL OVERALL LENGTH1.094 INCHES IN
CONNECTION TYPETHREADED EXTERNAL BOSS ALL ENDS
NOMINAL THREAD SIZE0.4375 INCHES FIRST END IN
NOMINAL THREAD SIZE0.3125 INCHES SECOND END IN
THREAD CLASS3A ALL ENDS A
THREAD QUANTITY PER INCH24 SECOND END
THREAD QUANTITY PER INCH20 FIRST END
MATERIALSTEEL COMP 321 OVERALL
THREAD SERIES DESIGNATORUNIFIED NATIONAL JOINT FINE (UNJF) ALL ENDS
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 MS21916-4-2R?
MS21916-4-2R is a REDUCER,BOSS.
What is the NSN for MS21916-4-2R?
MS21916-4-2R is cataloged in the U.S. Government catalog under NSN 4730-01-693-0283. 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.