Balls are manufactured to the precision requirements noted in ANSI/ABMA Std. 10A for steel balls and ASTM F2094 for ceramic balls. These standards require that balls meet the limits for ball diameter, spherical form and roughness noted below for each grade level. Lower grade numbers denote more precise balls, which help to improve accuracy, reduce running torque, lengthen lube life and reduce noise. With few exceptions, NHBB manufactures its precision bearings with grade 10A and 10C balls or better.
|BALL GRADE||VARIATION OF BALL DIAMETER
|DEVIATION FROM SPHERICAL FORM
|SURFACE ROUGHNESS RA MAX.|
|STEEL||CERAMIC||DEVIATION FROM BALL LOT DIAMETER (0.000001 IN.)|