GRADES AND TOLERANCES (ABMA STD-10)
(2.12) Grade: A specific combination of dimensional form and surface roughness tolerance, A ball grade is designated by a grade number.
(2.4) Ball Diameter Variation: The difference between the largest and the smallest actual single diameter of one ball.
(2.8) Lot Diameter Variation: The difference between the mean diameter of the largest and that of the smallest ball in the lot.
(2.9) Nominal Ball Diameter Tolerance: The maximum allowable deviation of any ball lot mean diameter from the nominal ball diameter.

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

BALL DIAMETER (ABMA STD—10)
(2.1) Nominal Ball Diameter: The diameter value that is used for the purpose of general identification of a ball size; e.g. 1/4”, 6mm,etc.
(2.13) Ball Gage: 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. A ball gage, in combination with the ball grade and nominal ball diameter, should be considered as the most exact ball size specification to be used by a customer for ordering purposes.
(2.11) Specific Diameter: The amount by which the lot mean diameter differs from the nominal diameter, accurate to the container marking increment for that grade. The specific diameter should be marked on the unit container.

HOW BALL DIAMETER IS INDICATED
Example:
Nominal Ball Diameter ………………. 3/8”
Ball Gage …………………………………… 3/8”+.0003
Specific Diameter ……………………… 3/8”+.000325

SURFACE QUALITIES
Surface Roughness: Surface roughness consists of all those irregularities which form surface relief and which are conventionally defined within the area where deviations of form and waviness are eliminated.
Waviness: The more widely spaced circumferential component of surface texture.

HUATONG GROUP BALL
STATEMENT OF STANDARD MEASUREMENT
CONDITIONS:

(Para. 2.2 and 3.5 1.3 ) Diameter: Between two parallel flat carbide gage surfaces under 4 oz. gage force with size corrected to zero gage pressure per AFBMA (ABMA) Std.10.
Deviation from Spherical Form: Determined by rotation of the ball against a linear transducer with less than 4 grams gage force. The resulting polar chart is interpreted using the minimum circumscribed circle method (MCC) per AFBMA (ABMA) Std. 10, Appendix A1.1 and AMS 889.3.
Surface Roughness: Determined by a stylus type instrument with the ball stationary. Compliance with Ra limits specified in AFBMA (AMBA) Std. 10, Table 3 will be interpreted using acutoff of .003 for a ball radii up to .050, .01 for ball radii up to .130 and .03 over .130, with filtration to optimize the number of cutoffs used to calculate the results.