The Tormek AngleMaster has two functions: you can use it to set the edge angle before sharpening or to measure the existing angle of a specific tool.

The edge angle can be set from 10° to 75°. The AngleMaster is designed to work on any grindstone diameter from 250 mm or 10" down to 150 mm or 6", so you can achieve an exact setting even as the stone wears.