V-parting tools are laid down on the outside bevel and moved along the sharpening stone, similar to paring chisels. It is important that pressure is only applied to the bevel, so that the bevel angle does not change. You must also make sure that you remove the same amount of material on both sides to ensure consistent blade geometry. Use a multiform stone for honing the inside as shown above. If the edges of this stone are not sharp enough, you can work on the sharpening stone first.
During sharpening of the V-tool, a small projection (nose) often forms in the middle of the cutting edge, because the blade is thicker in this angle than on the side walls. To prevent the unwanted projection, you should therefore round off the angle slightly before sharpening.