Another way is to prestretch the metal with a planishing hammer. Baileigh has a well priced planishing hammer that will do everything you need and comes with a good selection of dies... A planishing hammer with a flat die also works wonders for flatting things out that you've buggered up by hand. It really is one of those... "Why didn't I buy this before?" tools.
http://metal.baileighindustrial.com/...ammer-ph-24a-1
I'm warning you though... sell the bead roller and just walk away. This is how I started down the rabbit hole.... "but I just want to bead roll some firewall and apron panels...."
The bead roller leads to the planishing hammer.... the planishing hammer leads to the english wheel... the english wheel leads to the shrinker/stretcher... This all leads to your 30" 3-in-1 machine not being enough so you sell it at a swap meet and buy 48"-50" Shear and roller, and of course the regular brake isn't good enough when you can buy the magnetic brake.. Somewhere along the line you end up at a Baileigh Industrial class and come home with a power hammer and a plasma table... Lets not forget the band saws, the beverly shear, the power shear, the hand snips, the cleko pins, the hammers, dollies, anvils, dies for the bead roller and the hammers...... And then you have to buy or build stuff to store all of the dies and dollies and anvils....
Hello my name is Sean... and I started metal shaping....