Turning the oval bowl on a VOD is tricky and I was having trouble getting the bottom oval to be exactly in line with the top oval. The bowl has to be in the exact position when you take it off the chuck and place it in a donut chuck to finish the bottom. If the ovals are out even by 1 degree the bowl will appear to twist, its tricky to explain. I made a jig to hold the bowl in the exact position and this is the first bowl I tested it on.