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PartsTable / COMPONENT / MS51987-399
MS51987-399 ✓ 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

The PIN,SPRING is a the manufacturer industrial component. Key specifications include diameter: 0.125 INCHES NOMINAL IN, material: STEEL COMP 302 OVERALL, overall_length: 0.625 INCHES NOMINAL IN, style_designator: COILED, expanded_diameter: 0.131 INCHES MINIMUM AND 0.139 INCHES MAXIMUM IN, surface_treatment: PASSIVATE OVERALL. This product is currently in active production with full OEM support.

This part is cataloged in the Federal Logistics Information System (FLIS) under NSN 5315-01-173-3808, 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
MS51987-399
NSN: 5315-01-173-3808
FSC: 5315
CAGE: 96906 — MILITARY STANDARDS PROMULGATED BY MILITARY DEPARTMENTS UNDER AUTHORITY OF DEFENSE STANDARDIZATION MANUAL 4120 3-M
SPECIFICATIONS
diameter0.125 INCHES NOMINAL IN
materialSTEEL COMP 302 OVERALL
overall_length0.625 INCHES NOMINAL IN
style_designatorCOILED
expanded_diameter0.131 INCHES MINIMUM AND 0.139 INCHES MAXIMUM IN
surface_treatmentPASSIVATE OVERALL
material_document_and_classification66 FED STD SINGLE MATERIAL RESPONSE OVERALL
surface_treatment_document_and_classificationQQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
NSN5315-01-173-3808
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: MS51987-399 · 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
•
STYLE DESIGNATOR: COILED
•
SURFACE TREATMENT: PASSIVATE OVERALL
•
MATERIAL DOCUMENT AND CLASSIFICATION: 66 FED STD SINGLE MATERIAL RESPONSE OVERALL
•
MATERIAL: STEEL COMP 302 OVERALL
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: QQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
•
DIAMETER: 0.125 INCHES NOMINAL IN
•
EXPANDED DIAMETER: 0.131 INCHES MINIMUM AND 0.139 INCHES MAXIMUM IN
TECHNICAL CHARACTERISTICS (FLIS)
STYLE DESIGNATORCOILED
SURFACE TREATMENTPASSIVATE OVERALL
MATERIAL DOCUMENT AND CLASSIFICATION66 FED STD SINGLE MATERIAL RESPONSE OVERALL
MATERIALSTEEL COMP 302 OVERALL
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONQQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
OVERALL LENGTH0.625 INCHES NOMINAL IN
DIAMETER0.125 INCHES NOMINAL IN
EXPANDED DIAMETER0.131 INCHES MINIMUM AND 0.139 INCHES MAXIMUM IN
VERIFIED SUBSTITUTES & CROSS-REFERENCES 11
MIL-P10971EInterchangeable
interchangeable cross-reference
interchangeable
NAS1407N7M13Interchangeable
interchangeable cross-reference
interchangeable
NAS561-3-20Interchangeable
interchangeable cross-reference
interchangeable
125-0500MDPInterchangeable
interchangeable cross-reference
interchangeable
21128-00345Interchangeable
interchangeable cross-reference
interchangeable
MS51923-288Interchangeable
interchangeable cross-reference
interchangeable
LIFECYCLE
StatusACTIVE
AvailabilityOEM and secondary market
RoHS CompliantEAR99Not HAZMAT
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FREQUENTLY ASKED QUESTIONS
What is MS51987-399?
MS51987-399 is a PIN,SPRING.
What parts can replace MS51987-399?
There are 11 known substitutes for MS51987-399: MIL-P10971E, NAS1407N7M13, NAS561-3-20 and 8 more. Substitute compatibility should be verified for your specific system.
What is the NSN for MS51987-399?
MS51987-399 is cataloged in the Federal Logistics Information System (FLIS) under NSN 5315-01-173-3808. This indicates validated use in U.S. government and defense supply chains.
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✓ Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
PartsTable Design LLC · partstable.com
Last verified: July 2026