I have a 1/4" shank Rockler three wing slot cutting bit that cuts a 1/2" deep with the 7/8" bearing that came with it. Does anyone know offhand what size bearing it takes and whether the bearing can be replaced with a larger one? I'd like to have a 3/8" depth of cut and be able to use it without a fence on a curved piece of wood. Please let me know, thanks!