**GRADE
**
**
Grade
**
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.
**
**
**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.
**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 sphericity.
**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.
**
Grades (AFBMA) / Tolerances Chrome
and Stainless Steel Balls** |