Flat Washer Flat Washer Type Standard Dimensional Standards ASTM F844 Material Stainless Steel Material Grade/Class 18-8 Finish NL-19 For Screw Size 3/4 in Inside Diameter 0.781 in Outside Diameter 1 5/8 in Maximum Thickness 0.25 in System of Measurement Inch Minimum Thickness 0.25 in Color Silver Pack Size Small Pack Resistance Properties Corrosion Resistant Rockwell Hardness B70 Thickness Tolerance +/-0.010 in