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6566-40-631-4101 — WASHER,RECESSED

✓ Government record, cited
— · NUT WASHER
PRODUCT OVERVIEW

6566-40-631-4101: WASHER,RECESSED.

The WASHER,RECESSED is a the manufacturer industrial component. Key specifications include material: STEEL COMP 630 OVERALL, hole_diameter: 0.280 INCHES MINIMUM AND 0.290 INCHES MAXIMUM IN, outside_diameter: 0.780 INCHES NOMINAL IN, style_designator: RECESSED BOTH SIDES, top_recess_angle: 60.0 DEGREES NOMINAL, surface_treatment: PASSIVATE OVERALL. This part is cataloged in the U.S.

Government catalog under NSN 5310-01-124-3105, 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
6566-40-631-4101
NSN: 5310-01-124-3105
FSC: 5310 — Nuts and Washers
CAGE: 78286 — SIKORSKY AIRCRAFT CORPORATION DBA SIKORSKY AIRCRAFT CORP (USA)
SPECIFICATIONS
materialSTEEL COMP 630 OVERALL
hole_diameter0.280 INCHES MINIMUM AND 0.290 INCHES MAXIMUM IN
outside_diameter0.780 INCHES NOMINAL IN
style_designatorRECESSED BOTH SIDES
top_recess_angle60.0 DEGREES NOMINAL
surface_treatmentPASSIVATE OVERALL
material_thickness0.120 INCHES MINIMUM AND 0.125 INCHES MAXIMUM IN
bottom_recess_angle60.0 DEGREES NOMINAL
top_recess_diameter0.3146 INCHES MINIMUM AND 0.3246 INCHES MAXIMUM IN
bottom_recess_diameter0.3146 INCHES MINIMUM AND 0.3246 INCHES MAXIMUM IN
material_document_and_classificationAMS 5643 ASSN STD SINGLE MATERIAL RESPONSE OR AMS 5622 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
surface_treatment_document_and_classificationSS8435,FSCM 78286 MFR REF SINGLE TREATMENT RESPONSE OVERALL
NSN5310-01-124-3105
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: 6566-40-631-4101 · 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
•
TOP RECESS DIAMETER: 0.3146 INCHES MINIMUM AND 0.3246 INCHES MAXIMUM IN
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: SS8435,FSCM 78286 MFR REF SINGLE TREATMENT RESPONSE OVERALL
•
BOTTOM RECESS DIAMETER: 0.3146 INCHES MINIMUM AND 0.3246 INCHES MAXIMUM IN
•
TOP RECESS ANGLE: 60.0 DEGREES NOMINAL
•
STYLE DESIGNATOR: RECESSED BOTH SIDES
•
MATERIAL DOCUMENT AND CLASSIFICATION: AMS 5643 ASSN STD SINGLE MATERIAL RESPONSE OR AMS 5622 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
•
OUTSIDE DIAMETER: 0.780 INCHES NOMINAL IN
•
MATERIAL THICKNESS: 0.120 INCHES MINIMUM AND 0.125 INCHES MAXIMUM IN
TECHNICAL CHARACTERISTICS
TOP RECESS DIAMETER0.3146 INCHES MINIMUM AND 0.3246 INCHES MAXIMUM IN
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONSS8435,FSCM 78286 MFR REF SINGLE TREATMENT RESPONSE OVERALL
BOTTOM RECESS DIAMETER0.3146 INCHES MINIMUM AND 0.3246 INCHES MAXIMUM IN
TOP RECESS ANGLE60.0 DEGREES NOMINAL
STYLE DESIGNATORRECESSED BOTH SIDES
MATERIAL DOCUMENT AND CLASSIFICATIONAMS 5643 ASSN STD SINGLE MATERIAL RESPONSE OR AMS 5622 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
OUTSIDE DIAMETER0.780 INCHES NOMINAL IN
MATERIAL THICKNESS0.120 INCHES MINIMUM AND 0.125 INCHES MAXIMUM IN
BOTTOM RECESS ANGLE60.0 DEGREES NOMINAL
SURFACE TREATMENTPASSIVATE OVERALL
OTHER ITEMS IN FSC 5310 — Nuts and Washers
Items in the same Federal Supply class. No interchangeability or substitution relationship is implied.
5310-00-000-0040 5310-00-000-0077 5310-00-000-0079 5310-00-000-1146 5310-00-000-3815 5310-00-000-4532 5310-00-000-4540
SUBSTITUTES & CROSS-REFERENCES 2
65664-06314Reference document
Same NSN cross-reference
Reference document — Drawing number reference only
64-06314-101Reference document
Same NSN cross-reference
Reference document — Secondary reference
LIFECYCLE
NSN statusActive· U.S. Government catalog
Acquisition advice: Insurance item — stocked against contingency demandNo demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is 6566-40-631-4101?
6566-40-631-4101 is a WASHER,RECESSED.
What parts can replace 6566-40-631-4101?
There are 2 known substitutes for 6566-40-631-4101: 65664-06314, 64-06314-101. Substitute compatibility should be verified for your specific system.
What is the NSN for 6566-40-631-4101?
6566-40-631-4101 is cataloged in the U.S. Government catalog under NSN 5310-01-124-3105. 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.