Precision Balls

Precision balls are used in critical aeronautical bearings, guidance system balls for space and military applications, precision valves, automotive bearings and other applications where higher precision is necessary. Precision balls are defined by grade and they have tight tolerances and better surface finish. Abbott precision balls are available in Grade 3 to Grade 50 and available in the following materials: 300 series, 440C (DFARS, VIM/VAR, NON-DFARS), CHROME (DFARS, VIM/VAR, NON DFARS), M50, BG42, M4, TUNGSTEN CARBIDE, SILCON NITRATE, ALUMINA OXIDE and other materials upon request. Abbott conforms to both ABMA and ISO 3290 standards, which dictate the specific parameters associated with the grade of the ball.


The better the grade of the ball the closer to a perfect sphere a ball is made. Sphericity of a ball is critical for precision bearings, gyros and valve applications. The normal range of sphericity for precision balls is from grade 3 at +/-0.000003 to grade 50 +/- 0.00005.

Surface Integrity

or Tribology of a ball is critical to the surface-to-surface and/or surface-to-lubricant circumstances. Precision balls are required to have a better surface finish to ensure that the coefficient of wear is such that the ball has limited surface defects effecting the rotation of the ball as it passes through the bearing or other application. The better the surface finish, the less “noise” from vibration during bearing rotation. Surface finish can also be critical to providing a tight valve seal.


the better the grade of ball, the tighter the ball diameter tolerance: For example, an eighth-inch grade 3 ball has a diameter tolerance of ±0.00003, whereas an eighth-inch grade 200 semi-precision ball has a diameter tolerance of ±0.001. Diameter is critical for quiet bearings.