Slotting Cutter Arbors include a B5 bearing for 1/2" depth of cut. Use the following for different cut depths.
B20 bearing for 9/16" depth of cut
B25 bearing for 3/8" depth of cut
B26 bearing for 1/4" depth of cut
B27 bearing for 5/8" depth of cut
All of our router bits are made by the award winning Whiteside Machine Company.