Flat Washer Flat Washer Type Standard Dimensional Standards ASME B18.22.1 Material Steel Material Grade/Class Class 8.8 Finish Black Oxide For Screw Size 5/8 in Outside Diameter 1 3/8 in Maximum Thickness 0.125 in System of Measurement Inch Minimum Thickness 0.125 in Color Clear Inside Diameter Tolerance 0.651-0.671 Made in North America No Manufacturer Location Globally Sourced Material Quality Standards ASTM A-325 Maximum Temperature 350 Degrees C