PartsTable
Technical Data Sheet
PartsTable / COMPONENT / MS51818-3S
MS51818-3S ✓ Verified by PartsTable
— · HOSE FITTING
WHAT YOU NEED TO KNOW
PTFE tape on tapered threads (NPT/BSPT) JIC/AN flare connections seal metal-to-metal — no tape
NPT != BSPT — look identical, NOT interchangeable
PRODUCT OVERVIEW

The ADAPTER,STRAIGHT,TUBE TO BOSS is a the manufacturer industrial component. Key specifications include material: STEEL CORROSION RESISTING OVERALL, leg_length: 0.891 INCHES NOMINAL SECOND END IN, seat_angle: 37.0 DEGREES FIRST END, thread_class: 2A SECOND END A, connection_type: THREADED EXTERNAL TUBE FIRST END, connection_style: FLARELESS (TUBE) SECOND END. This product is currently in active production with full OEM support.

This part is cataloged in the Federal Logistics Information System (FLIS) under NSN 4730-01-311-8357, 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
MS51818-3S
NSN: 4730-01-311-8357
FSC: 4730
CAGE: 96906 — MILITARY STANDARDS PROMULGATED BY MILITARY DEPARTMENTS UNDER AUTHORITY OF DEFENSE STANDARDIZATION MANUAL 4120 3-M
SPECIFICATIONS
materialSTEEL CORROSION RESISTING OVERALL
leg_length0.891 INCHES NOMINAL SECOND END IN
seat_angle37.0 DEGREES FIRST END
thread_class2A SECOND END A
connection_typeTHREADED EXTERNAL TUBE FIRST END
connection_styleFLARELESS (TUBE) SECOND END
nominal_thread_size0.438 INCHES FIRST END IN
media_for_which_designedHYDRAULIC FLUID SINGLE RESPONSE
thread_series_designatorUNIFIED NATIONAL JOINT FINE (UNJF) FIRST END
nondefinitive_spec/std_data22D FIGURE
specification/standard_data81343-J514 PROFESSIONAL/INDUSTRIAL ASSOCIATION STANDARD AND 96906-MS51818 GOVERNMENT STANDARD
furnished_items_and_quantity2 TUBE COUPLING NUT W/SLEEVE
NSN4730-01-311-8357
COMPONENT DIAGRAM
HOSE FITTING — THREAD TYPE IS CRITICAL END A: — STRAIGHT END B: — SPECIFICATIONS Thread: — Material: — Pressure: — PN: MS51818-3S · 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
•
THREAD CLASS: 2A FIRST END A
•
NOMINAL OUTSIDE DIAMETER TUBE ACCOMMODATED: 0.250 INCHES SECOND END IN
•
CONNECTION TYPE: THREADED EXTERNAL TUBE FIRST END
•
NOMINAL THREAD SIZE: 0.438 INCHES SECOND END IN
•
LEG LENGTH: 0.891 INCHES NOMINAL FIRST END IN
•
SEAT ANGLE: 37.0 DEGREES FIRST END
TECHNICAL CHARACTERISTICS (FLIS)
THREAD CLASS2A FIRST END A
NOMINAL OUTSIDE DIAMETER TUBE ACCOMMODATED0.250 INCHES SECOND END IN
CONNECTION TYPETHREADED EXTERNAL TUBE FIRST END
NOMINAL THREAD SIZE0.438 INCHES SECOND END IN
CONNECTION TYPETHREADED EXTERNAL TUBE SECOND END
LEG LENGTH0.891 INCHES NOMINAL FIRST END IN
NOMINAL OUTSIDE DIAMETER TUBE ACCOMMODATED0.250 INCHES FIRST END IN
SEAT ANGLE37.0 DEGREES FIRST END
NOMINAL THREAD SIZE0.438 INCHES FIRST END IN
MATERIALSTEEL CORROSION RESISTING OVERALL
VERIFIED SUBSTITUTES & CROSS-REFERENCES 16
C5515X20Interchangeable
interchangeable cross-reference
interchangeable
2503-20-20Interchangeable
interchangeable cross-reference
interchangeable
107A-0091Interchangeable
interchangeable cross-reference
interchangeable
J514 12-12-12 080428SAInterchangeable
interchangeable cross-reference
interchangeable
J514Interchangeable
interchangeable cross-reference
interchangeable
12-R5BU-SSInterchangeable
interchangeable cross-reference
interchangeable
LIFECYCLE
StatusACTIVE
AvailabilityOEM and secondary market
RoHS CompliantEAR99Not HAZMAT
Ready to buy MS51818-3S?
Compare prices from verified sellers on eBay
Buy on eBay →
As an eBay Partner, PartsTable may earn a commission. Your price is not affected.
FREQUENTLY ASKED QUESTIONS
What is MS51818-3S?
MS51818-3S is a ADAPTER,STRAIGHT,TUBE TO BOSS.
What parts can replace MS51818-3S?
There are 16 known substitutes for MS51818-3S: C5515X20, 2503-20-20, 107A-0091 and 13 more. Substitute compatibility should be verified for your specific system.
What is the NSN for MS51818-3S?
MS51818-3S is cataloged in the Federal Logistics Information System (FLIS) under NSN 4730-01-311-8357. This indicates validated use in U.S. government and defense supply chains.
Community Feedback
Comments (0)
No comments yet. Be the first to share what you know.
Leave a Comment
Comments are reviewed before appearing. You will receive an email to verify before your comment appears.

Request a Quote — MS51818-3S

✓ Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
PartsTable Design LLC · partstable.com
Last verified: July 2026