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MS21915-5-4 — ADAPTER,STRAIGHT,TUBE TO BOSS

✓ Government record, cited
— · HOSE FITTING
PRODUCT OVERVIEW

MS21915-5-4: ADAPTER,STRAIGHT,TUBE TO BOSS.

The ADAPTER,STRAIGHT,TUBE TO BOSS is a the manufacturer industrial component. Key specifications include material: STEEL COMP 1137 OR STEEL COMP 1141 OR STEEL COMP 4130 OR STEEL COMP 4140 OVERALL, reducer_type: CONCENTRIC, thread_class: 3B FIRST END, connection_type: THREADED INTERNAL BOSS FIRST END, connection_style: GASKET SEAL (BOSS) FIRST END, surface_treatment: CADMIUM OUTSIDE. This part is cataloged in the U.S.

Government catalog under NSN 4730-00-403-4358, 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
MS21915-5-4
NSN: 4730-00-403-4358
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 OR STEEL COMP 4130 OR STEEL COMP 4140 OVERALL
reducer_typeCONCENTRIC
thread_class3B FIRST END
connection_typeTHREADED INTERNAL BOSS FIRST END
connection_styleGASKET SEAL (BOSS) FIRST END
surface_treatmentCADMIUM OUTSIDE
nominal_thread_size0.500 INCHES FIRST END IN
nominal_overall_length1.281 INCHES IN
thread_series_designatorUNIFIED NATIONAL JOINT FINE (UNJF) ALL ENDS
material_document_and_classificationQQ-S-637 FED SPEC 1ST MATERIAL RESPONSE AND QQ-S-637 FED SPEC 2ND MATERIAL RESPONSE AND MIL-S-6758 MIL SPEC 3RD MATERIAL RESPONSE AND MIL-S-5626 MIL SPEC 4TH MATERIAL RESPONSE OVERALL
surface_treatment_document_and_classificationQQ-P-416,TY 1,CL 2 FED SPEC SINGLE TREATMENT RESPONSE INSIDE
NSN4730-00-403-4358
COMPONENT DIAGRAM
HOSE FITTING — THREAD TYPE IS CRITICAL END A: — STRAIGHT END B: — SPECIFICATIONS Thread: — Material: — Pressure: — PN: MS21915-5-4 · 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: QQ-P-416,TY 1,CL 2 FED SPEC SINGLE TREATMENT RESPONSE OUTSIDE
•
CONNECTION STYLE: EXTERNAL SEAT FOR GASKET SEAL (BOSS) SECOND END
•
NOMINAL OVERALL LENGTH: 1.281 INCHES IN
•
CONNECTION TYPE: THREADED INTERNAL BOSS FIRST END
•
MATERIAL DOCUMENT AND CLASSIFICATION: QQ-S-637 FED SPEC 1ST MATERIAL RESPONSE AND QQ-S-637 FED SPEC 2ND MATERIAL RESPONSE AND MIL-S-6758 MIL SPEC 3RD MATERIAL RESPONSE AND MIL-S-5626 MIL SPEC 4TH MATERIAL RESPONSE OVERALL
TECHNICAL CHARACTERISTICS
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONQQ-P-416,TY 1,CL 2 FED SPEC SINGLE TREATMENT RESPONSE OUTSIDE
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONQQ-P-416,TY 1,CL 2 FED SPEC SINGLE TREATMENT RESPONSE INSIDE
CONNECTION STYLEEXTERNAL SEAT FOR GASKET SEAL (BOSS) SECOND END
CONNECTION STYLEGASKET SEAL (BOSS) FIRST END
NOMINAL OVERALL LENGTH1.281 INCHES IN
CONNECTION TYPETHREADED INTERNAL BOSS FIRST END
CONNECTION TYPETHREADED EXTERNAL BOSS SECOND END
MATERIAL DOCUMENT AND CLASSIFICATIONQQ-S-637 FED SPEC 1ST MATERIAL RESPONSE AND QQ-S-637 FED SPEC 2ND MATERIAL RESPONSE AND MIL-S-6758 MIL SPEC 3RD MATERIAL RESPONSE AND MIL-S-5626 MIL SPEC 4TH MATERIAL RESPONSE OVERALL
NOMINAL THREAD SIZE0.438 INCHES SECOND END IN
NOMINAL THREAD SIZE0.500 INCHES FIRST END IN
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
AS18280Reference document
Same NSN cross-reference
Reference document — Secondary reference
AS21915Reference 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 MS21915-5-4?
MS21915-5-4 is a ADAPTER,STRAIGHT,TUBE TO BOSS.
What parts can replace MS21915-5-4?
There are 2 known substitutes for MS21915-5-4: AS18280, AS21915. Substitute compatibility should be verified for your specific system.
What is the NSN for MS21915-5-4?
MS21915-5-4 is cataloged in the U.S. Government catalog under NSN 4730-00-403-4358. 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.