There have been various threads on holding bowls to finish the bottoms. Here is my solution. I bought the large Mega Jaws from Oneway and liked them for reversing bowls and finishing the bottoms. The problem was the largest dia. bowl I could hold was about 14 1/2" dia, I was turning bowls in the 20 to 24" range on a regular basis. So I decided to expand the jig. I bought some square Aluminum stock from Lowes and set up a jig for my drill press. I drilled and tapped a series of holes to give me a 24" capacity. I sent pictures to Oneway and they where totally disinterested.