The one ton has a slightly larger opening capacity, making it accomodate a slimline without modification. The half-ton needs some work to make this happen.
Otherwise, a half ton is certainly enough pressure to crack any pen you make!!![][][][]
I hae the 1/2 ton. Used it off and on until I built one. It works fine for most kits. If you bolt it down to a base, you can remove the plate and have more room for longer stuff!
It sounds like it might be where you get one. I have the ½ ton from HF, bolt it down and when you do a longer pen just turn the plate and it gives you more length.
Bob
I don't know if mine is 1/2 or 1 ton.. there is enough room on the plate to press most parts, but have to move the plate to insert transmissions.. I had to modify it slightly by putting a block of hardwood with a formica top between the toes of the press (under the plate) so I don't damage anything while I press the transmission.