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MS21904D8 — INJECTOR ASSEMBLY,FUEL

✓ Government record, cited
— · HOSE FITTING
PRODUCT OVERVIEW

MS21904D8: INJECTOR ASSEMBLY,FUEL.

The INJECTOR ASSEMBLY,FUEL is a the manufacturer industrial component. Key specifications include material: ALUMINUM ALLOY 7075 OVERALL, flow_angle: 90.0 DEGREES, leg_length: 1.250 INCHES MINIMUM AND 1.297 INCHES MAXIMUM ALL ENDS IN, seat_angle: 12.0 DEGREES ALL ENDS, thread_class: 3A ALL ENDS A, connection_type: THREADED EXTERNAL TUBE ALL ENDS. This part is cataloged in the U.S.

Government catalog under NSN 4730-00-640-5091, 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
MS21904D8
NSN: 4730-00-640-5091
FSC: 4730 — Hose, Pipe, Tube, Lubrication, and Railing Fittings
CAGE: 96906 — MILITARY STANDARDS PROMULGATED BY MILITARY DEPARTMENTS UNDER AUTHORITY OF DEFENSE STANDARDIZATION MANUAL 4120 3-M
SPECIFICATIONS
materialALUMINUM ALLOY 7075 OVERALL
flow_angle90.0 DEGREES
leg_length1.250 INCHES MINIMUM AND 1.297 INCHES MAXIMUM ALL ENDS IN
seat_angle12.0 DEGREES ALL ENDS
thread_class3A ALL ENDS A
connection_typeTHREADED EXTERNAL TUBE ALL ENDS
connection_styleFLARELESS (TUBE) ALL ENDS
surface_treatmentANODIZE OVERALL
nominal_thread_size0.750 INCHES ALL ENDS IN
thread_series_designatorUNIFIED NATIONAL JOINT FINE (UNJF) FIRST END
specification/standard_dataSAE AS21904 PROFESSIONAL/INDUSTRIAL ASSOCIATION STANDARD
material_document_and_classificationQQ-A-225/4,T6 FED SPEC SINGLE MATERIAL RESPONSE OR QQ-A-225/6,T4 FED SPEC SINGLE MATERIAL RESPONSE OVERALL
NSN4730-00-640-5091
COMPONENT DIAGRAM
HOSE FITTING — THREAD TYPE IS CRITICAL END A: — STRAIGHT END B: — SPECIFICATIONS Thread: — Material: — Pressure: — PN: MS21904D8 · 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
•
FLOW ANGLE: 90.0 DEGREES
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: MIL-A-8625,TY 2,CL 2 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL
•
CONNECTION STYLE: FLARELESS (TUBE) ALL ENDS
•
CONNECTION TYPE: THREADED EXTERNAL TUBE ALL ENDS
•
MATERIAL DOCUMENT AND CLASSIFICATION: QQ-A-225/4,T6 FED SPEC SINGLE MATERIAL RESPONSE OR QQ-A-225/6,T4 FED SPEC SINGLE MATERIAL RESPONSE OVERALL
•
NOMINAL OUTSIDE DIAMETER TUBE ACCOMMODATED: 0.500 INCHES ALL ENDS IN
•
LEG LENGTH: 1.250 INCHES MINIMUM AND 1.297 INCHES MAXIMUM ALL ENDS IN
•
NOMINAL THREAD SIZE: 0.750 INCHES ALL ENDS IN
TECHNICAL CHARACTERISTICS
FLOW ANGLE90.0 DEGREES
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONMIL-A-8625,TY 2,CL 2 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL
CONNECTION STYLEFLARELESS (TUBE) ALL ENDS
CONNECTION TYPETHREADED EXTERNAL TUBE ALL ENDS
MATERIAL DOCUMENT AND CLASSIFICATIONQQ-A-225/4,T6 FED SPEC SINGLE MATERIAL RESPONSE OR QQ-A-225/6,T4 FED SPEC SINGLE MATERIAL RESPONSE OVERALL
NOMINAL OUTSIDE DIAMETER TUBE ACCOMMODATED0.500 INCHES ALL ENDS IN
LEG LENGTH1.250 INCHES MINIMUM AND 1.297 INCHES MAXIMUM ALL ENDS IN
NOMINAL THREAD SIZE0.750 INCHES ALL ENDS IN
SEAT ANGLE12.0 DEGREES ALL ENDS
SPECIFICATION/STANDARD DATASAE AS21904 PROFESSIONAL/INDUSTRIAL ASSOCIATION STANDARD
SUBSTITUTES & CROSS-REFERENCES 6
ER821D8Reference document
Same NSN cross-reference
Reference document — Secondary reference
AS18280Reference document
Same NSN cross-reference
Reference document — Secondary reference
AS21904Reference document
Same NSN cross-reference
Reference document — Secondary reference
MS24665-376Reference document
Same NSN cross-reference
Reference document — Advisory reference — outside the item-of-supply concept
MS21904W8Reference document
Same NSN cross-reference
Reference document — Secondary reference
SAE-AS18280Reference document
Same NSN cross-reference
Reference document — Design control — primary reference
LIFECYCLE
NSN statusActive· U.S. Government catalog
No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is MS21904D8?
MS21904D8 is a INJECTOR ASSEMBLY,FUEL.
What parts can replace MS21904D8?
There are 6 known substitutes for MS21904D8: ER821D8, AS18280, AS21904 and 3 more. Substitute compatibility should be verified for your specific system.
What is the NSN for MS21904D8?
MS21904D8 is cataloged in the U.S. Government catalog under NSN 4730-00-640-5091. 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.