A washer having a centrally located hole with a solid or laminated cross-section and two flat parallel bearing surfaces. The hole must be 75 percent or less than the largest dimension and the bearing surface finish is greater than 32 microinch (0.8 micrometer). The thickness cannot exceed 25 percent of the largest outside dimension. When the largest outside dimension is less than 1/4 inch or 6mm, the thickness must be 0.006 inches (0.15mm) or greater and for items 1/4 inch (6mm) or larger, the thickness must be 0.016 inches (0.4mm) or greater. The maximum tolerance is applied to dimensions and used as a determining factor. Items with separable lamination use shim. For items fabricated from ceramic or electrically rated materials by specification or industry standards use insulator (1), washer. Excludes disk, valve, graphite impregnated and lubricated items.
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National Aeronautics and Space Administration 
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Netherlands 
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NATO Maintenance and Supply Agency Classification: Cotters, cotter-pins, washers and similar articles, of aluminum
NSN 5905-01-024-1822
NSN 6645-01-025-1002
NSN 5895-00-110-5731
NSN 5855-01-612-5116
NSN 5975-01-572-6932
NSN 5905-01-130-3875
NSN 6135-01-599-7563
NSN 6685-01-415-0574
NSN 6220-01-130-2701
NSN 5835-00-187-1481
NSN 5925-01-297-1933
NSN 5975-01-586-6978