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W21AL9-8-20 — WASHER,FLAT

✓ Government record, cited
— · NUT WASHER
PRODUCT OVERVIEW

W21AL9-8-20: WASHER,FLAT.

The WASHER,FLAT is a the manufacturer industrial component. Key specifications include material: ALUMINUM ALLOY 2024 OVERALL, thickness: 0.020 INCHES NOMINAL IN, hole_diameter: 0.140 INCHES NOMINAL IN, overall_diameter: 0.250 INCHES NOMINAL IN, peripheral_shape_style: ROUND, center_hole_shape_style: ROUND. This part is cataloged in the U.S.

Government catalog under NSN 5310-00-660-3181, 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
W21AL9-8-20
NSN: 5310-00-660-3181
FSC: 5310 — Nuts and Washers
CAGE: 43999 — THE BOEING COMPANY DIV LEGACY AM&M (USA)
SPECIFICATIONS
materialALUMINUM ALLOY 2024 OVERALL
thickness0.020 INCHES NOMINAL IN
hole_diameter0.140 INCHES NOMINAL IN
overall_diameter0.250 INCHES NOMINAL IN
peripheral_shape_styleROUND
center_hole_shape_styleROUND
cross-sectional_shape_styleRECTANGULAR
specification/standard_data43999-2W1 MANUFACTURERS STANDARD
material_document_and_classificationQQ-A-362 FED SPEC SINGLE MATERIAL RESPONSE OVERALL
NSN5310-00-660-3181
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: W21AL9-8-20 · 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
•
OVERALL DIAMETER: 0.250 INCHES NOMINAL IN
•
MATERIAL DOCUMENT AND CLASSIFICATION: QQ-A-362 FED SPEC SINGLE MATERIAL RESPONSE OVERALL
•
CROSS-SECTIONAL SHAPE STYLE: RECTANGULAR
•
SPECIFICATION/STANDARD DATA: 43999-2W1 MANUFACTURERS STANDARD
•
PERIPHERAL SHAPE STYLE: ROUND
•
MATERIAL: ALUMINUM ALLOY 2024 OVERALL
•
CENTER HOLE SHAPE STYLE: ROUND
•
HOLE DIAMETER: 0.140 INCHES NOMINAL IN
TECHNICAL CHARACTERISTICS
OVERALL DIAMETER0.250 INCHES NOMINAL IN
MATERIAL DOCUMENT AND CLASSIFICATIONQQ-A-362 FED SPEC SINGLE MATERIAL RESPONSE OVERALL
CROSS-SECTIONAL SHAPE STYLERECTANGULAR
SPECIFICATION/STANDARD DATA43999-2W1 MANUFACTURERS STANDARD
PERIPHERAL SHAPE STYLEROUND
MATERIALALUMINUM ALLOY 2024 OVERALL
CENTER HOLE SHAPE STYLEROUND
HOLE DIAMETER0.140 INCHES NOMINAL IN
THICKNESS0.020 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 W21AL9-8-20?
W21AL9-8-20 is a WASHER,FLAT.
What is the NSN for W21AL9-8-20?
W21AL9-8-20 is cataloged in the U.S. Government catalog under NSN 5310-00-660-3181. 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.