I am trying to figure out how these 7 ton splitters get 7 tons. They mostly all say they have a pump pressure of 2320psi. Its hard to find other specs on them, but several say the diameter of the ram is 1 5/8 This puts the area at 2.07 so the force is only 4809lbs. What am I missing? Even if I go with the outside diameter of the cylinder of 2 5/8 I only get 12549lbs. Still not 7 ton. Thanks.