That IS a good tool, and shows a lot of thought in it's creation.
I believe that David is the "Compleat Handyman" by all the nifty tools he creates. Grand handywork, always.
I must have a simpler mind, because I am trying to come up with a way to make that tool without a lathe. Perhaps a pivoting bar with a sliding stylus - set the radius on the bar and tighten a set screw when you have the radius correct. That would provide the scribed circle, if you used a centerpiece of the correct diameter for your particular bore. I see that Mr. Rase is using separate punch holes on the various radii.
There remains the angular separation between the dots, but that could be solved with a protractor, OR you could line up with a land or a groove. Even David's nice tool doesn't do that for you.
Our wonderful Mr. Rase is keeping my mind fertile! Many thanks.