Hi Greenie
I would use the tooltip or a scribing block to get it close to centre but using the clock ensures the work piece is definitely running concentric and leaves nothing to chance by eye. It is amazing how close you can get things by eye as proof in the video. The first side was a total of 0.008” and the other was spot on. But if I hadn’t used this method one set of the flats would have had this error. Check twice cut once