Hi I can't find the web site any more it was an American desert race car fab shop but I did save the drawings.
I made the frame out of 50 x50 x 5mm wall, the plates are 10mm, the punch and die are just bright steel bar stock and the jack is a 12 ton of fleebay and I put the 2 plates in the die for 6mm, I did have a chart for tonnage required depending on the width of the Die but you can find them on the net.
If you make it as the plans it will make up to 60 deg folds.
I'm on the look out for a narrower die for thin stuff now.
Simon/