[route56wingnut]

My solution to a long lasting version of this is to bore a hole in a bar stock piece not all the way through so as to have the end of the chisel bit fits tight in it. Now weld this to a thin wall piece of tubing either round or square depending on the product you choose to use for your forming . I also weld a nut so to use a set screw to pinch against the insert. Streck Tools also has a similar tool that is made of a composit material that has a hole for a chisel bit in it. I drove the bit out the end and started ruining the panel I was trying to form . After doing this to multiple pieces and having Streck nicely replace at no cost I finally contacted their Tech guy and he asked what I was using for a hammer source and of course proudly stated I was using Snap Ons bad boy These are way too powerful for this process as well as most rivet guns as their piston is too heavy and not needed for flow forming. I looked in the back of the droor for an old cheap muffler gun and that was the answer