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 Air Force 
Dept. of the Navy Classification: Washers other than lock washers, iron or steel
NSN 5990-00-226-1152
NSN 5835-01-190-5192
NSN 6650-01-613-8467
NSN 5985-01-299-8177
NSN 5920-00-975-9834
NSN 5950-01-054-4127
NSN 5895-01-421-4487
NSN 6645-01-106-6369
NSN 2925-01-074-2718
NSN 5996-01-456-0488
NSN 6320-00-483-0451
NSN 6320-01-370-5222