| Definations |
| Nominal
ball diameter - Dw |
|
The
diameter value that is used for the purpose of general identification
of a ball size.
|
| Single
Diameter of a bal l- Dws |
|
The
distance between two parallel planes tangent to the surface of the
ball.
|
| Mean
Diameter of a ball - Dwm |
|
The
arithmetical mean of the largest and the smallest single diameters
of the ball.
|
| Ball
diameter variation - VDws |
|
The
different between the largest and the smallest single diameters of
the ball.
|
| Deviation
from spherical form - tDw |
|
The
greatest radial distance in any radial plane between a sphere circumscribed
around the ball surface and any pointon the ball surface.
|
| Lot |
|
A definite quantity of balls manufactured under conditions which are
presumed uniform and which is considered and identified as an entity.
|
| Lot
Mean Diameter - DwmL |
|
The
arithmetical mean of the mean diameterof the largest ball and that
of the smallest ball in the lot.
|
| Lot
diameter variation - VDWL |
|
The
difference between the mean diameter of the largest ball and that
of the smallest ball in the lot.
|
| Gauge
interval - IG |
|
One
of the intervals into which the deviation of the nominal diameter
of ball is divided.
|
| Ball
Grade |
|
A
specific combination of dimensional, form, and surface roughness tolerances.
A ball grade is designated by a grade number.
|
| Preferred
gauge - S |
|
The
prescribed small amount by which the lot mean diameter should differ
from nominal diameter, this amount being one of an established series
of amounts. Each ball gauge is a whole multiple of the ball precision
grade. The ball gauge, combined with the precision grade and the nominal
ball diameter can be considered the most correct dimensional identification
to pass orders.
|
| Deviation
from ball gauge - ΔS |
|
Difference
between the lot mean diameter and the sum of the nominal ball diameter
and the ball gauge.
|
| Ball
subgauge |
|
The
selected amount of an established series of amounts. It is the closest
one to the real deviation from ball gauge. Each ball sub-gauge is
whole multiple of the interval subgauge fixed for the ball grade.
The ball sub - gauge is used by supplier to specify the lot mean diameter
but must not be used by purchaser to order.
|
| Hardness
|
|
The
measure of resistance to penetration of ball surface or truncated
flat of the ball by a specified indenting shape as determined by specified
methods.
|
| Surface
roughness - Ra |
|
Consist
of all those irregularities which from surface relief and which are
conventionally defined within the area where deviations of form and
waviness are eliminated.
|
