Sharpening chisels for morticing machines doesn't get much easier than this. Fit the multi-flute conical reamer with the appropriate size pilot piece, just a few turns removes a tiny amount of metal from the chisel's internal bevel. Using the fine diamond honing stone included with the kit touches up the outer faces of the chisel by removing any burrs thrown up by the reamer, it's as simple as that. A sharp chisel cuts cleaner and is far less prone to burning and, of course, puts far less strain on the morticing machine. It leaves the internal faces of the mortice smoother and cleaner making for a better fitting joint. This Axminster mortice chisel sharpening kit will fit most Taiwanese and Japanese mortice chisels metric and imperial sizes up to 12mm/1/2". N.B. Touch up the chisels auger at the same time using a simple triangular needle or saw file.