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AT520 — WASHER,LOCK

✓ Government record, cited
— · NUT WASHER
PRODUCT OVERVIEW

AT520: WASHER,LOCK.

The WASHER,LOCK is a the manufacturer industrial component. Key specifications include material: STEEL OVERALL, hole_diameter: 0.409 INCHES NOMINAL IN, outside_diameter: 0.528 INCHES NOMINAL IN, style_designator: GIRDER SECTION, surface_treatment: ZINC AND CHROMATE OVERALL, material_thickness: 0.039 INCHES NOMINAL IN. This part is cataloged in the U.S.

Government catalog under NSN 5310-01-379-4178, 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
AT520
NSN: 5310-01-379-4178
FSC: 5310 — Nuts and Washers
CAGE: 63426 — NKK SWITCHES OF AMERICA INC (USA)
SPECIFICATIONS
materialSTEEL OVERALL
hole_diameter0.409 INCHES NOMINAL IN
outside_diameter0.528 INCHES NOMINAL IN
style_designatorGIRDER SECTION
surface_treatmentZINC AND CHROMATE OVERALL
material_thickness0.039 INCHES NOMINAL IN
NSN5310-01-379-4178
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: AT520 · 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: GIRDER SECTION
•
OUTSIDE DIAMETER: 0.528 INCHES NOMINAL IN
•
MATERIAL THICKNESS: 0.039 INCHES NOMINAL IN
•
SURFACE TREATMENT: ZINC AND CHROMATE OVERALL
•
MATERIAL: STEEL OVERALL
•
HOLE DIAMETER: 0.409 INCHES NOMINAL IN
TECHNICAL CHARACTERISTICS
STYLE DESIGNATORGIRDER SECTION
OUTSIDE DIAMETER0.528 INCHES NOMINAL IN
MATERIAL THICKNESS0.039 INCHES NOMINAL IN
SURFACE TREATMENTZINC AND CHROMATE OVERALL
MATERIALSTEEL OVERALL
HOLE DIAMETER0.409 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
Acquisition advice: Normally procured from the manufacturer (OEM)No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is AT520?
AT520 is a WASHER,LOCK.
What is the NSN for AT520?
AT520 is cataloged in the U.S. Government catalog under NSN 5310-01-379-4178. 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.