Glossary of Ball Terms
The ball grade (G) is a specific combination of dimensional,
form, surface roughness and sorting tolerance for balls. For
example, the level of sphericity, expressed in millionths of
an inch, e.g., a Grade 10 ball must be round or spherical within
10 millionths of an inch. The grade designation also dictates
the other tolerances, per the chart shown below. Click here for
a link to our ball grades page.
Variation of Ball Diameter (VDws)
Tthe difference between the largest and the smallest
of the single diameters of a ball.
Variation of Ball Lot Diameter (VDwL)
The difference between the mean diameters of the largest
ball and smallest ball in a ball lot.
Definite quantity of balls manufactured under conditions
presumed uniform and which is considered as an entity.
Deviation from Spherical Form
The difference between the largest and smallest diameters
measurable on a single ball. Also referred to as roundness or
Surface Roughness (Ra)
Surface irregularities with relatively small spacings,
which usually include irregularities resulting from the method
of manufacture being used and/or other influences.