A CNC grinding machine process is used to produce the tooth profile on angle and straight faced spur gears. The process uses a pair of grinding wheels (1.1,1.2) that have a tooth profile formed around the periphery. The tip form is accurately sized by a dressing wheel (6) that is moved in a controlled manner in two axes (R,P) as it is rotated. The size and separation distance between the grinding wheels are determined by a measuring element (4) that is moved into contact with the wheels. Simple geometric relationships allows accurate values to be determined. ADVANTAGE - Simplifies wheel position settings.