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1818216 — WASHER,FLAT

✓ Government record, cited
— · NUT WASHER
PRODUCT OVERVIEW

1818216: WASHER,FLAT.

The WASHER,FLAT is a the manufacturer industrial component. Key specifications include width: 0.400 INCHES NOMINAL IN, material: STEEL COMP 301 OVERALL, thickness: 0.090 INCHES NOMINAL IN, hole_diameter: 0.210 INCHES NOMINAL IN, surface_treatment: PASSIVATE OVERALL, peripheral_shape_style: ELLIPTICAL. This part is cataloged in the U.S.

Government catalog under NSN 5310-01-285-4361, 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
1818216
NSN: 5310-01-285-4361
FSC: 5310 — Nuts and Washers
CAGE: 03956 — NORTHROP GRUMMAN SYSTEMS CORPORATION (USA)
SPECIFICATIONS
width0.400 INCHES NOMINAL IN
materialSTEEL COMP 301 OVERALL
thickness0.090 INCHES NOMINAL IN
hole_diameter0.210 INCHES NOMINAL IN
surface_treatmentPASSIVATE OVERALL
peripheral_shape_styleELLIPTICAL
center_hole_shape_styleROUND
cross-sectional_shape_styleRECTANGULAR
material_document_and_classificationMIL-S-5059,CL 301 MIL SPEC SINGLE MATERIAL RESPONSE OVERALL
surface_treatment_document_and_classificationQQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
NSN5310-01-285-4361
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: 1818216 · 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 TREATMENT DOCUMENT AND CLASSIFICATION: QQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
•
MATERIAL DOCUMENT AND CLASSIFICATION: MIL-S-5059,CL 301 MIL SPEC SINGLE MATERIAL RESPONSE OVERALL
•
CROSS-SECTIONAL SHAPE STYLE: RECTANGULAR
•
SURFACE TREATMENT: PASSIVATE OVERALL
•
PERIPHERAL SHAPE STYLE: ELLIPTICAL
•
WIDTH: 0.400 INCHES NOMINAL IN
•
MATERIAL: STEEL COMP 301 OVERALL
•
CENTER HOLE SHAPE STYLE: ROUND
TECHNICAL CHARACTERISTICS
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONQQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
MATERIAL DOCUMENT AND CLASSIFICATIONMIL-S-5059,CL 301 MIL SPEC SINGLE MATERIAL RESPONSE OVERALL
CROSS-SECTIONAL SHAPE STYLERECTANGULAR
SURFACE TREATMENTPASSIVATE OVERALL
PERIPHERAL SHAPE STYLEELLIPTICAL
WIDTH0.400 INCHES NOMINAL IN
MATERIALSTEEL COMP 301 OVERALL
CENTER HOLE SHAPE STYLEROUND
HOLE DIAMETER0.210 INCHES NOMINAL IN
THICKNESS0.090 INCHES NOMINAL 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
No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is 1818216?
1818216 is a WASHER,FLAT.
What is the NSN for 1818216?
1818216 is cataloged in the U.S. Government catalog under NSN 5310-01-285-4361. 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.