I have a beautiful burl cap whose maximum dimension is exactly the maximum diameter my lathe can handle. In fact I may have to grease one of the tips to get it to side across the ways. I don't want to cut anything off the edge, because I will lose the natural edge in that spot, and I want it continuous around the entire edge. How do I measure an odd shaped blank, and find the exact center? I can get close by measuring multiple spans, and dividing by 2, but because of the tight tolerances, I need to be more exact. Surely somebody has figured out a way to find the exact center. I'll try and get a pic uploaded as soon as possible. TIA for your help.