Precision Ball Grading Standards

At Wulian yiheballs measure precision balls by the following grading standards:

Grade – The grade is a measure of the degree of precision of the ball with respect to key functional characteristics. A lower number indicates a more precise metal ball. For example, a grade 10 ball is more precise than a grade 1000 ball.

Diameter – Available in both inch and metric; ranging from 0.8mm to 19.05mm

Sphericity – The higher sphericity means how close a precision ball is to being a perfect sphere. Also called roundness.

Surface Roughness – The quality of a ball’s surface finish. 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.

in my factory Small balls size : 1mm 1.2mm 1.3mm 1.4mm 1.5mm 1/16''  1.7mm 1.8mm 2.mm 3/32'' 2.5mm 3mm 1/8''  (aisi304 aisi316 aisi 440c aisi420c Gcr15 )