20 MM Used to cut a flexible water pipe, but the mountain of flex was crushed at the time of cutting. I did the next shoulder operation, but the mountain was crushed, so I could not make a brim without clean. Since it is only one mountain to hit the roller part at the time of cutting, it seems that the force is overloaded and the mountain is crushed. If you let the roller part a little longer, I think that the force will not disperse and collapse to other mountains.