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 3/4 in Inside Diameter 0.781 in Outside Diameter 1 7/16 in Maximum Thickness 0.141 in System of Measurement Inch Minimum Thickness 0.141 in Inside Diameter Tolerance 0.781 to 0.803 in Outside Diameter Tolerance 1.417 in to 1.447 in Pack Size Small Pack Rockwell Hardness 38HRC