First of all a shank is round like on a bowl gouge and a tang is flat on scrapers and skews. Why is the shank on all bowl and spindle gouges are turned down to a common fractional size? This is because high quality tool steel is sold .015 oversize so the shank needs to be turned down to a common size to fit all the aftermarket handles and so a common drill bit can be used to bore a wood handle. Example; a 1/2 diameter tool will have a shank that measures .500 What is the shank length? On the 3/8 and ½ diameter tools the shank is 2 inches long. The 5/8 and ¾ diameter tools are 2-1/2 inches in length. The 1-1/4 inch SRG have a ¾ inch diameter shank that is 2-1/2 inches long.   All tangs are 2 inches long. On the 1/2 and 3/4 inch scrapers and skews the tang will fit in a 1/2 inch nose. The larger scrapers and skews will fit in a 5/8 nose.