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ER919D10-4 — REDUCER,BOSS

✓ Government record, cited
— · HOSE FITTING
PRODUCT OVERVIEW

ER919D10-4: 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, special_features: WEAPON SYSTEM ESSENTIAL. This part is cataloged in the U.S.

Government catalog under NSN 4730-00-640-5857, 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
ER919D10-4
NSN: 4730-00-640-5857
FSC: 4730 — Hose, Pipe, Tube, Lubrication, and Railing Fittings
CAGE: 79470 — DANA CORP WEATHERHEAD DIV (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
special_featuresWEAPON SYSTEM ESSENTIAL
surface_treatmentANODIZE OVERALL
operating_pressure3000.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS
nominal_thread_size0.438 INCHES SECOND END IN
maximum_operating_temp-65.0 FAHRENHEIT SECOND RESPONSE DEGF
nominal_overall_length1.438 INCHES IN
end_item_identificationUSED ON BOEING VERTOL MODEL CH-47 CARGO TRANSPORT HELICOPTER; HELLICOPTER, CHINOOK, CH-47
NSN4730-00-640-5857
COMPONENT DIAGRAM
HOSE FITTING — THREAD TYPE IS CRITICAL END A: — STRAIGHT END B: — SPECIFICATIONS Thread: — Material: — Pressure: — PN: ER919D10-4 · 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
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: MIL-A-8625,TY 2,CL 2 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL
•
CONNECTION STYLE: EXTERNAL SEAT FOR GASKET SEAL (BOSS) ALL ENDS
•
NOMINAL OVERALL LENGTH: 1.438 INCHES IN
•
CRITICALITY CODE JUSTIFICATION: FEAT
•
CONNECTION TYPE: THREADED EXTERNAL BOSS ALL ENDS
•
MATERIAL DOCUMENT AND CLASSIFICATION: QQ-A-225/6,T6 FED SPEC SINGLE MATERIAL RESPONSE OVERALL
•
OPERATING PRESSURE: 3000.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS
•
NOMINAL THREAD SIZE: 0.438 INCHES SECOND END IN
TECHNICAL CHARACTERISTICS
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONMIL-A-8625,TY 2,CL 2 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL
CONNECTION STYLEEXTERNAL SEAT FOR GASKET SEAL (BOSS) ALL ENDS
NOMINAL OVERALL LENGTH1.438 INCHES IN
CRITICALITY CODE JUSTIFICATIONFEAT
CONNECTION TYPETHREADED EXTERNAL BOSS ALL ENDS
MATERIAL DOCUMENT AND CLASSIFICATIONQQ-A-225/6,T6 FED SPEC SINGLE MATERIAL RESPONSE OVERALL
OPERATING PRESSURE3000.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS
NOMINAL THREAD SIZE0.438 INCHES SECOND END IN
NOMINAL THREAD SIZE0.875 INCHES FIRST END IN
SPECIFICATION/STANDARD DATA96906-MS21916 GOVERNMENT STANDARD
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 2
AS21916Reference document
Same NSN cross-reference
Reference document — Secondary reference
MS21916D10-4Reference document
Same NSN cross-reference
Reference document — Secondary reference
LIFECYCLE
NSN statusActive· U.S. Government catalog
No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is ER919D10-4?
ER919D10-4 is a REDUCER,BOSS.
What parts can replace ER919D10-4?
There are 2 known substitutes for ER919D10-4: AS21916, MS21916D10-4. Substitute compatibility should be verified for your specific system.
What is the NSN for ER919D10-4?
ER919D10-4 is cataloged in the U.S. Government catalog under NSN 4730-00-640-5857. 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.