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.
Dept. of the Navy 
Canada 
Italy 
Turkey Classification: Gaskets, washers and other seals, of vulcanized rubber other than hard rubber
NSN 4140-01-168-7685
NSN 6135-01-116-3385
NSN 6135-01-454-9408
NSN 5855-01-597-8638
NSN 6145-01-442-8143
NSN 5905-01-429-1240
NSN 5965-01-052-3765
NSN 5895-01-481-4261
NSN 6135-01-518-9813
NSN 2925-01-658-4470
NSN 2925-00-853-5039
NSN 6650-01-148-1841