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Ball Grades

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.

Individual Balls

BALL GRADE VARIATION OF BALL DIAMETER
(0.000001 IN.)
DEVIATION FROM SPHERICAL FORM
(0.000001 IN.)
SURFACE ROUGHNESS RA MAX.
STEEL CERAMIC STEEL CERAMIC
G3A 3C 3 3 0.40 0.15
G5A 5C 5 5 0.56 0.20
G10A 10C 10 10 0.80 0.25
G16A 16C 16 16 1.00 0.35
G24A 24C 24 24 2.60 0.50

Lots

BALL GRADE
STEEL CERAMIC DEVIATION FROM BALL LOT DIAMETER (0.000001 IN.)
G3A 3C 5
G5A 5C 10
G10A 10C 20
G16A 16C 32
G24A 24C 48