Fender Washer Flat Washer Type Oversized Dimensional Standards ASME B18.22.1 Material Steel Material Grade/Class Grade 2 Finish Zinc Plated For Screw Size 5/16 in Inside Diameter 0.344 in Outside Diameter 1 5/8 in Maximum Thickness 0.08 in System of Measurement Inch Minimum Thickness 0.051 in Color Silver Inside Diameter Tolerance +/-0.010 in Outside Diameter Tolerance +/-0.010 in Pack Size Small Pack Rockwell Hardness B55 Thickness Tolerance +0.005/-0.004 in