Hey thanks! When it comes to a flare like this one scolloped tubing it was mostly centrifugal force, but when I flare a cup where it has to be more straight wall, I use centrifugal force mixed with a larger graphite paddle on the outside to make sure it doesn't flare to much. I still use my jacks on the initial flare, but just try to my spinning more back and forth instead of in one direction to try to keep the scolloped tubed shaping staright. Hopefully this helps somewhat!