I was inspired to make a Center Finder
as I did not want to drive 20 miles or pay extra bucks for a store-bought model.
Upon doing a search, I found https://www.instructables.com/id/Make-a-Center-Finder/
posted by Phil B.
I just like to minimize my time working with metal, so I built a drawing, used MDF
(can you imagine?) and cut the pieces out at TechShop in San Jose - www.techshop.ws.
Above, you see what the completed finder looks like...