Semi-ground 3000 Series bearings are designed for adaptation to a majority of precision bearing applications. Careful heat treatment provides a uniform and exact degree of hardness for maximum life. The 3000 Series bearings are precision ground to close tolerances on the O.D. (Outside Diameter) with exceptional care given to the ball grooves. The bore is semi-ground. A ball retainer, or separator, is used to increase the range of allowable speeds by reducing ball-to-ball contact friction. RBC Nice Bearings is a subsidiary of RBC Bearings. RBC Bearings has been providing bearing solutions to our customers since 1919. A publicly-traded company (NASDAQ: ROLL), RBC currently has 23 manufacturing facilities worldwide, with 18 located in the USA.