SAE Washer Flat Washer Type SAE Dimensional Standards ASME B18.22.1 Type A Narrow SAE Standard Material Steel Material Grade/Class Grade 2 Finish Black Oxide For Screw Size 3/8 in Inside Diameter 0.406 in Outside Diameter 13/16 in Maximum Thickness 0.063 in System of Measurement Inch Minimum Thickness 0.063 in Pack Size Bulk Pack Rockwell Hardness 38HRC Thickness Tolerance +/-0.015 in Package Quantity 7000