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PartsTable / COMPONENT / MS21042-4
MS21042-4 ✓ Verified by PartsTable
— · NUT WASHER
WHAT YOU NEED TO KNOW
Match nut grade to bolt grade for full strength Lock nuts prevent loosening under vibration
Don't mix grades — weakens the joint
PRODUCT OVERVIEW

NUT,SELF-LOCKING,EXTENDED WASHER. Key specifications include material: STEEL CORROSION RESISTING OVERALL, nut_style: HEXAGON, thread_series: UNIFIED NATIONAL JOINT FINE (UNJF), overall_height: 0.204 INCHES MINIMUM AND 0.219 INCHES MAXIMUM IN, locking_feature: PREVAILING TORQUE ALL METAL DESIGN, thread_direction: RIGHT-HAND. This part is cataloged in the Federal Logistics Information System (FLIS) under NSN 5310-00-807-1468, 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
MS21042-4
NSN: 5310-00-807-1468
FSC: 5310
CAGE: A0126 — LEONARDO SPA HELICOPTERS DIVISION - PRODUCTION SITE (ITA)
SPECIFICATIONS
materialSTEEL CORROSION RESISTING OVERALL
nut_styleHEXAGON
thread_seriesUNIFIED NATIONAL JOINT FINE (UNJF)
overall_height0.204 INCHES MINIMUM AND 0.219 INCHES MAXIMUM IN
locking_featurePREVAILING TORQUE ALL METAL DESIGN
thread_directionRIGHT-HAND
washer_thickness0.019 INCHES MINIMUM IN
width_across_flats0.304 INCHES MINIMUM AND 0.316 INCHES MAXIMUM IN
nominal_thread_size0.250 INCHES IN
end_item_identification4910-01-539-6129
washer_outside_diameter0.420 INCHES MAXIMUM IN
thread_quantity_per_inch28
NSN5310-00-807-1468
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: MS21042-4 · OEM ⚠ VERIFY BEFORE ORDERING Grade matters for torque spec — don't mix grades. A Grade 5 nut on a Grade 8 bolt weakens the joint. Lock nuts, wing nuts, and castle nuts are NOT interchangeable with standard hex ✓ BROKER TIP Match nut to bolt thread class and material. Stainless bolt + zinc nut = galvanic corrosion. Always verify finish matches (plain, zinc, hot-dip galvanized) PARTSTABLE TECHNICAL DRAWING — NOT TO SCALE
VERIFIED SUBSTITUTES & CROSS-REFERENCES 25
EMR1A1Interchangeable
interchangeable cross-reference
interchangeable
6-62902Interchangeable
interchangeable cross-reference
interchangeable
MS20364-428CInterchangeable
interchangeable cross-reference
interchangeable
80127ADXInterchangeable
interchangeable cross-reference
interchangeable
80127Interchangeable
interchangeable cross-reference
interchangeable
97-048Interchangeable
interchangeable cross-reference
interchangeable
LIFECYCLE
StatusCANCELLED
Availability—
RoHS CompliantEAR99Not HAZMAT
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FREQUENTLY ASKED QUESTIONS
What is MS21042-4?
MS21042-4 is a NUT,SELF-LOCKING,EXTENDED WASHER.
What parts can replace MS21042-4?
There are 25 known substitutes for MS21042-4: EMR1A1, 6-62902, MS20364-428C and 22 more. Substitute compatibility should be verified for your specific system.
Is MS21042-4 still available?
MS21042-4 is currently cancelled.
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✓ Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
PartsTable Design LLC · partstable.com
Last verified: July 2026