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 7/8 in Inside Diameter 0.938 in Outside Diameter 1 5/8 in Maximum Thickness 0.156 in System of Measurement Inch Minimum Thickness 0.156 in Inside Diameter Tolerance 0.939 to 0.965 in Outside Diameter Tolerance 1.614 in to 1.644 in Pack Size Small Pack Rockwell Hardness 38HRC