Has anyone used the MKII to sharpen chisels? My chisels keep turning in the jig so that the blade is no longer square to the jig. I have tightened the thing up but the chisels still move. I am thinking of making is little block with a groove in it to keep the chisel square to the jig. Am I doing something wrong here? I have used this jig to sharpen my plane blades and it worked great but for chisels it seems to be have trouble holding them tight. Any help would be greatly appreciated.