Create Your Own Custom 20mm Worktop—No CNC Required, A highly accurate means of laying out a pattern of 20mm holes in a work surface, this system makes the task both quick and easy. Thanks to the high precision CNC machining used to perfectly position the registration holes along the two Parf sticks and some classic geometry (the Pythagorean theorem, to be specific), the Parf Guide System produces highly accurate hole positions at near CNC accuracy. With an accurate pattern of 20mm holes and a set of our Bench Dogs, you will be able to make the perfect right angle or 45° cuts with your guide rail and track saw.