

A specific combination of
dimensional form and surface roughness
tolerance. A ball grade is designated by a grade
number.   


The diameter value that is used
for the purpose of general identification of a
ball size. Measured by two parallel plane
tangent to the surface of the
ball.   


The arithmetical mean of the
largest and the smallest single diameter of the
ball.   


The arithmetical mean of the
mean diameter of the largest ball and that of
the smallest balls in the lot. Lot is the
definite quantity of ball manufactured under
uniformed
condition.   


The difference between the mean
diameter of the largest ball and that of the
smallest ball in the
lot.   


The maximum allowable deviation
of any ball mean diameter from the nominal ball
diameter   
Deviation from
Spherical Form  
 

The greatest radial distance in
any radial plane between a sphere circumscribed
around the ball surface and any point on the
ball
surface.   


Surface roughness consists of
all those irregularities such as crack, cuts and
dent, which surface relief. And it is
conventionally defined within the area where
deviation of form are
eliminated.   


The measure of resistance to
penetration of the ball surface or truncated
flat of the ball by a specific indenting
shape.   


The distance measured radially
from the surface of the ball to the point where
the ball hardness becomes HRC 50. This term is
applicable to case hardened ball
only.   