Description says that it will accept UP TO 20 gauge mild steel. Thats only .039" or just over 1/32" thick. Maybe a really, really thin cracker crust? I dunno'.
The rolls will open much wider then that, that is the machines capacity in terms of the thickness of metal it can form. It would need to be more robust to form a heavier gauge, like say 16 gauge mild steel.
The only problem using this as a dough sheeter is the third roller in the back. That's the important part for it's intended purpose but will just get in the way for use as a sheeter. I'm sure it can be removed, but to spend a couple hundred bucks on a sheeter and then have to modify it.....