Abutments for sealed bearings
The diameter of the shaft abutment should not exceed da max (→ product tables) at least for the 1 to 2 mm closest to the bearing, to prevent interference with the seal (fig. 2). If the bearings are to be located axially on the shaft by a lock nut, SKF recommends using a KMFE lock nut (fig. 3) or a spacer ring (fig. 4) between the bearing and the lock washer to prevent interference with the seal.