Self-Aligning Ball Bearing 1307 Self-aligning ball bearing has two rows of spherical balls, the outer race provides a common concave spherical raceway, while the inner race provides two concave spherical raceways that form an angle with the bearing axis. The curvature center of the outer raceway is consistent with the bearing center. The self-aligning ball bearing is self-adjusted, and it is not affected by non-centering or shaft deformation flexure of shaft and bearing block, so it can compensate the concentricity error caused by these reasons.