Grinding a Thumbnail Gouge
The 40 degree solution to sharpening gouges
Wood turner Mike Mahoney details the correct way to grind a bowl or spindle gouge, keeping its distinctive fingernail profile and a cutting edge beveled at a consistent angle along the curved end of the tool. Proper bevel is crucial — in this case, 40 degrees. Mahoney’s freehand method makes use a template on the grinder that enables you to get that important, consistent 40-degree bevel on your gouge.
From Fine Woodworking #187