I cut up a trashcan full of cardboard into small pieces just to see what happened. It did get a little dull, but it took an ungodly amount of cutting to do it. I decided to move the edge to 20 degrees. That is not easy even with a 12x2.5 inch diamond stone. It is most assuredly hard and very tough. From what little I have done with it the steel looks like it will handle 20 degrees without blinking.
