The 7/8ths inch tubing wanted to lift off of the table while I was bending it. Being the resourceful guy that I am I took two pieces of 7/8th inch tubing, spanned it with the straightest thing I had in my shop (a 4 foot level), took two pieces of plywood and screwed them down over top of the level to hold it down. As you can see, I slid the tubing I was working on underneath of the jig I made. No lifting, problem solved. Not pretty... but I'm not here to make nice looking jigs.