If you want to go to the orginal post of this information check:ChevyNomad said:Oak Park had a very good guide. I'll see if I can attatch them. I've never tried to include or attach a picture in the forum before.
Take one half the guide diameter and subtract one half of the bit diameter.
That is the distance from the guide bushing to the final cut edge.
Hope this helps
If you use the search function there is a lot more information in the forum. I also posted some of my table in the gallery area if they are of interest to you.