Semi Precision Balls

semi-precision balls are used in a wide variety of applications where the higher tolerances and cost of precision balls is not necessary. Balls are defined by grade: The lower the number of the grade, the more precision to which the ball is manufactured. The typical distinction between a precision ball and a semi-precision ball is between grades 50 and 100, wherein grades 50 and below are considered precision balls and grades 100 and above are semi-precision.

Surface Integrity is defined as the surface smoothness and freedom from defects such as flats, pits, soft spots and cuts. Semi-precision balls must be free of such defects when inspected without magnification.

Size is the mean diameter, measured between two parallel planes on the ball surface. Tolerances for semi-precision balls are A 0.0005 (grade 100) up to A 0.005 (grade 1000).