Skew Cutter – High Speed Steel The Robert Sorby Skew Cutter is excellent for getting into those tight corners when a clean square edge is required. This cutter is one of 14 that support a range of tools and offer incredible flexibility to the turner. Sharpening: Use a diamond file or honing stone flat across the top face. To gain best results and increase the longevity of the cutter this simple procedure should be done little and often. Sharpening can be achieved with the cutter mounted on the tool. Alternatively use the 472 cutter holder to reshape the profile on the Robert Sorby ProEdge or on a grinding wheel.