I have some old Z&H literature. It goes like this. Z&H rate the press as the square of the number. 5=25 ton, #7=50 ton, #8 1/2=75ton,
#10=100 ton, #12=150 ton. The tonnage is somewhat(a small fraction) adjustable by stacking hardened plates under the die. The percussion press hits hardest on the last fraction of the drive wheel. Here are some pictures of the machines I have left. I love them like my dogs!My dogs take up less room!
John
Asking price is as follows: Z&H #5-$900, #7-$1,900, #12- $3,500 , Osterwalder 125-$4,000