I knew that sharping s110v would be tough, but wow that tough! Thought I had a good start to reprofiling my knife but I was very humbled by my over confidence, it looked good, was scary sharp for a short time but that was it. I'm using an edgepro but is seems that it is going to be a long, long process, using just the stones that came with the unit. Worked awesome on my other knives, it took them to a new level of sharpness. Any suggestions on what stones or techniques to use on harder steels?