1018 Carbon Steel Ball Material Carbon Steel Material Grade 1018 Ball Bearing Grade 500 Ball Weight 1.05 g Outside Diameter 1/4 in Rockwell Hardness C60 to C67 Mechanical Finish Polished Machinability Not Rated Standards ABMA ANSI Outside Diameter Tolerance +/-0.002 in Brinell Hardness 640 Application Bearings Industrial Shape Ball System of Measurement Inch Package Quantity 250