I have done up to a 9x10" plate with a 1 ton arbor press. The thing is you can't do it all at once. I start in one corner and press. Move over 1" (the size of the ram) and press. Rinse and repeat until you've covered the entire area. Yes, yes I know - it's time consuming but unless you want to spend a bunch of money on a hydraulic press, take the time. Additionally, a friend over at salty dog leather is making these add-ons for the arbor press which might help. cheers!