I just used my New SB250 stone. What Jeff said was true. I had to find out for myself. Next time I will listen to Jeff. It did a nice job on knifes. But not as good as the White stone. On my chipper blades did better than the white stone.But you do have to use the grading stone more. The SB250 is a much harder stone for sure and will probably last longer. The white stone is going to be the all around stone for me.