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6566-20-381-3101 — WASHER,SHOULDERED AND RECESSED

✓ Government record, cited
— · NUT WASHER
PRODUCT OVERVIEW

6566-20-381-3101: WASHER,SHOULDERED AND RECESSED.

The WASHER,SHOULDERED AND RECESSED is a the manufacturer industrial component. Key specifications include material: STEEL COMP 630 OVERALL, recess_angle: 85.0 DEGREES MINIMUM AND 95.0 DEGREES MAXIMUM, hole_diameter: 0.192 INCHES MINIMUM AND 0.195 INCHES MAXIMUM IN, surface_finish: 64.0 MICROINCHES ALL SURFACES, recess_diameter: 0.218 INCHES MINIMUM AND 0.234 INCHES MAXIMUM IN, shoulder_height: 0.115 INCHES MINIMUM AND 0.130 INCHES MAXIMUM IN. This part is cataloged in the U.S.

Government catalog under NSN 5310-01-124-1270, 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
6566-20-381-3101
NSN: 5310-01-124-1270
FSC: 5310 — Nuts and Washers
CAGE: 78286 — SIKORSKY AIRCRAFT CORPORATION DBA SIKORSKY AIRCRAFT CORP (USA)
SPECIFICATIONS
materialSTEEL COMP 630 OVERALL
recess_angle85.0 DEGREES MINIMUM AND 95.0 DEGREES MAXIMUM
hole_diameter0.192 INCHES MINIMUM AND 0.195 INCHES MAXIMUM IN
surface_finish64.0 MICROINCHES ALL SURFACES
recess_diameter0.218 INCHES MINIMUM AND 0.234 INCHES MAXIMUM IN
shoulder_height0.115 INCHES MINIMUM AND 0.130 INCHES MAXIMUM IN
outside_diameter0.985 INCHES MINIMUM AND 0.990 INCHES MAXIMUM IN
special_featuresCHAMFER OUTSIDE LEFT CORNER AND OUTSIDE RIGHT CORNER OF FLANGE 0.030 IN. BY 45 DEG IN
style_designatorSHOULDERED AND RECESSED BOTH SIDES
shoulder_diameter0.615 INCHES MINIMUM AND 0.620 INCHES MAXIMUM IN
surface_treatmentPASSIVATE OVERALL
material_thickness0.120 INCHES MINIMUM AND 0.125 INCHES MAXIMUM IN
NSN5310-01-124-1270
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: 6566-20-381-3101 · 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
•
SURFACE FINISH: 64.0 MICROINCHES ALL SURFACES
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: SS8435,FSCM 78286 MFR REF SINGLE TREATMENT RESPONSE OVERALL
•
SHOULDER HEIGHT: 0.115 INCHES MINIMUM AND 0.130 INCHES MAXIMUM IN
•
STYLE DESIGNATOR: SHOULDERED AND RECESSED BOTH SIDES
•
MATERIAL DOCUMENT AND CLASSIFICATION: AMS 5643 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
•
OUTSIDE DIAMETER: 0.985 INCHES MINIMUM AND 0.990 INCHES MAXIMUM IN
•
MATERIAL THICKNESS: 0.120 INCHES MINIMUM AND 0.125 INCHES MAXIMUM IN
•
SHOULDER DIAMETER: 0.615 INCHES MINIMUM AND 0.620 INCHES MAXIMUM IN
TECHNICAL CHARACTERISTICS
SURFACE FINISH64.0 MICROINCHES ALL SURFACES
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONSS8435,FSCM 78286 MFR REF SINGLE TREATMENT RESPONSE OVERALL
SHOULDER HEIGHT0.115 INCHES MINIMUM AND 0.130 INCHES MAXIMUM IN
STYLE DESIGNATORSHOULDERED AND RECESSED BOTH SIDES
MATERIAL DOCUMENT AND CLASSIFICATIONAMS 5643 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
OUTSIDE DIAMETER0.985 INCHES MINIMUM AND 0.990 INCHES MAXIMUM IN
MATERIAL THICKNESS0.120 INCHES MINIMUM AND 0.125 INCHES MAXIMUM IN
SHOULDER DIAMETER0.615 INCHES MINIMUM AND 0.620 INCHES MAXIMUM IN
RECESS DIAMETER0.218 INCHES MINIMUM AND 0.234 INCHES MAXIMUM IN
SPECIAL FEATURESCHAMFER OUTSIDE LEFT CORNER AND OUTSIDE RIGHT CORNER OF FLANGE 0.030 IN. BY 45 DEG IN
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

No substitute or cross-reference records for this part.

LIFECYCLE
NSN statusActive· U.S. Government catalog
Acquisition advice: Normally procured from the manufacturer (OEM)No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is 6566-20-381-3101?
6566-20-381-3101 is a WASHER,SHOULDERED AND RECESSED.
What is the NSN for 6566-20-381-3101?
6566-20-381-3101 is cataloged in the U.S. Government catalog under NSN 5310-01-124-1270. 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.