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MS51988-3 — NUT,SELF-LOCKING,EXTENDED WASHER

✓ Government record, cited
— · NUT WASHER
PRODUCT OVERVIEW

MS51988-3: NUT,SELF-LOCKING,EXTENDED WASHER.

NUT,SELF-LOCKING,EXTENDED WASHER. Key specifications include material: STEEL OVERALL, nut_style: HEXAGON, lubrication: DRY FILM LUBRICANT, thread_class: 2B, thread_series: UNIFIED NATIONAL COARSE (UNC), overall_height: 0.300 INCHES MAXIMUM IN. This part is cataloged in the U.S.

Government catalog under NSN 5310-00-159-1577, 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
MS51988-3
NSN: 5310-00-159-1577
FSC: 5310 — Nuts and Washers
CAGE: 96906 — MILITARY STANDARDS PROMULGATED BY MILITARY DEPARTMENTS UNDER AUTHORITY OF DEFENSE STANDARDIZATION MANUAL 4120 3-M
SPECIFICATIONS
materialSTEEL OVERALL
nut_styleHEXAGON
lubricationDRY FILM LUBRICANT
thread_class2B
thread_seriesUNIFIED NATIONAL COARSE (UNC)
overall_height0.300 INCHES MAXIMUM IN
hardness_rating24.0 ROCKWELL C MINIMUM AND 32.0 ROCKWELL C MAXIMUM
locking_featurePREVAILING TORQUE ALL METAL DESIGN
thread_directionRIGHT-HAND
washer_thickness0.040 INCHES MINIMUM AND 0.060 INCHES MAXIMUM IN
surface_treatmentCADMIUM AND CHROMATE OVERALL
width_across_flats0.4280 INCHES MINIMUM AND 0.4385 INCHES MAXIMUM IN
NSN5310-00-159-1577
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: MS51988-3 · 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
KEY FEATURES
•
LUBRICATION: DRY FILM LUBRICANT
•
WASHER OUTSIDE DIAMETER: 0.560 INCHES MAXIMUM IN
•
WIDTH ACROSS FLATS: 0.4280 INCHES MINIMUM AND 0.4385 INCHES MAXIMUM IN
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: QQ-P-416,TY 2,CL 3 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
•
THREAD SERIES: UNIFIED NATIONAL COARSE (UNC)
•
HARDNESS RATING: 24.0 ROCKWELL C MINIMUM AND 32.0 ROCKWELL C MAXIMUM
•
WASHER THICKNESS: 0.040 INCHES MINIMUM AND 0.060 INCHES MAXIMUM IN
TECHNICAL CHARACTERISTICS
LUBRICATIONDRY FILM LUBRICANT
OVERALL HEIGHT0.300 INCHES MAXIMUM IN
WASHER OUTSIDE DIAMETER0.560 INCHES MAXIMUM IN
WIDTH ACROSS FLATS0.4280 INCHES MINIMUM AND 0.4385 INCHES MAXIMUM IN
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONQQ-P-416,TY 2,CL 3 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
THREAD SERIESUNIFIED NATIONAL COARSE (UNC)
HARDNESS RATING24.0 ROCKWELL C MINIMUM AND 32.0 ROCKWELL C MAXIMUM
WASHER THICKNESS0.040 INCHES MINIMUM AND 0.060 INCHES MAXIMUM IN
THREAD DIRECTIONRIGHT-HAND
NOMINAL THREAD SIZE0.250 INCHES IN
SUBSTITUTES & CROSS-REFERENCES 1
MIL-N-45913Reference document
Same NSN cross-reference
Reference document — Identification reference
LIFECYCLE
NSN statusCancelled· U.S. Government catalog
No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is MS51988-3?
MS51988-3 is a NUT,SELF-LOCKING,EXTENDED WASHER.
What parts can replace MS51988-3?
There is 1 known substitute for MS51988-3: MIL-N-45913. Substitute compatibility should be verified for your specific system.
What is the NSN for MS51988-3?
MS51988-3 is cataloged in the U.S. Government catalog under NSN 5310-00-159-1577. This indicates validated use in U.S. government and defense supply chains.
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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.