Flat Washer Type B Flat Washer Type Standard Dimensional Standards ASME B18.22.1 Material Steel Material Grade/Class Grade 2 Finish Zinc Plated For Screw Size 1 1/4 in Inside Diameter 1.312 in Outside Diameter 3 1/2 in Maximum Thickness 0.266 in System of Measurement Inch Minimum Thickness 0.234 in Color Silver Inside Diameter Tolerance +/-0.010 in Outside Diameter Tolerance +/-0.010 in Pack Size Small Pack Rockwell Hardness B55 Thickness Tolerance -0.014 in/ +0.005 in