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558405 — WASHER,FLAT

✓ Government record, cited
— · NUT WASHER
PRODUCT OVERVIEW

558405: WASHER,FLAT.

The WASHER,FLAT is a the manufacturer industrial component. Key specifications include length: 1.180 INCHES MINIMUM AND 1.200 INCHES MAXIMUM IN, material: ALUMINUM ALLOY 6061 OVERALL, thickness: 0.050 INCHES MINIMUM AND 0.070 INCHES MAXIMUM IN, hole_diameter: 0.180 INCHES MINIMUM AND 0.200 INCHES MAXIMUM IN, hardness_rating: 49.5 ROCKWELL SUPERFICIAL 30-T MINIMUM, surface_treatment: ANODIZE OVERALL. This part is cataloged in the U.S.

Government catalog under NSN 5310-00-985-3423, 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
558405
NSN: 5310-00-985-3423
FSC: 5310 — Nuts and Washers
CAGE: 73030 — HAMILTON SUNDSTRAND CORPORATION DBA COLLINS AEROSPACE (USA)
SPECIFICATIONS
length1.180 INCHES MINIMUM AND 1.200 INCHES MAXIMUM IN
materialALUMINUM ALLOY 6061 OVERALL
thickness0.050 INCHES MINIMUM AND 0.070 INCHES MAXIMUM IN
hole_diameter0.180 INCHES MINIMUM AND 0.200 INCHES MAXIMUM IN
hardness_rating49.5 ROCKWELL SUPERFICIAL 30-T MINIMUM
surface_treatmentANODIZE OVERALL
width_across_flats0.350 INCHES MINIMUM AND 0.370 INCHES MAXIMUM IN
peripheral_shape_styleRECTANGULAR
center_hole_shape_styleROUND
cross-sectional_shape_styleRECTANGULAR
material_document_and_classificationQQ-A-250/11 FED SPEC SINGLE MATERIAL RESPONSE OVERALL
surface_treatment_document_and_classificationMIL-A-8625 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL
NSN5310-00-985-3423
COMPONENT DIAGRAM
NUT & WASHER — GRADE MATCHING REQUIRED Hex NUT CROSS-SECTION WASHER OD: — SIZE: — MATERIAL: — PN: 558405 · 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
•
WIDTH ACROSS FLATS: 0.350 INCHES MINIMUM AND 0.370 INCHES MAXIMUM IN
•
LENGTH: 1.180 INCHES MINIMUM AND 1.200 INCHES MAXIMUM IN
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: MIL-A-8625 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL
•
HARDNESS RATING: 49.5 ROCKWELL SUPERFICIAL 30-T MINIMUM
•
MATERIAL DOCUMENT AND CLASSIFICATION: QQ-A-250/11 FED SPEC SINGLE MATERIAL RESPONSE OVERALL
•
CROSS-SECTIONAL SHAPE STYLE: RECTANGULAR
•
SURFACE TREATMENT: ANODIZE OVERALL
•
PERIPHERAL SHAPE STYLE: RECTANGULAR
TECHNICAL CHARACTERISTICS
WIDTH ACROSS FLATS0.350 INCHES MINIMUM AND 0.370 INCHES MAXIMUM IN
LENGTH1.180 INCHES MINIMUM AND 1.200 INCHES MAXIMUM IN
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONMIL-A-8625 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL
HARDNESS RATING49.5 ROCKWELL SUPERFICIAL 30-T MINIMUM
MATERIAL DOCUMENT AND CLASSIFICATIONQQ-A-250/11 FED SPEC SINGLE MATERIAL RESPONSE OVERALL
CROSS-SECTIONAL SHAPE STYLERECTANGULAR
SURFACE TREATMENTANODIZE OVERALL
PERIPHERAL SHAPE STYLERECTANGULAR
MATERIALALUMINUM ALLOY 6061 OVERALL
CENTER HOLE SHAPE STYLEROUND
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 558405?
558405 is a WASHER,FLAT.
What is the NSN for 558405?
558405 is cataloged in the U.S. Government catalog under NSN 5310-00-985-3423. 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.