Here's a very simple but effective setup for a multi-purposehydraulic press. The cylinder is a 20 ton Enerpac. It's sold asa "portapower" type tool. The pump, which I highly recommend,has a pressure gauge, 5 gallon reservoir and costs (if memoryserves) around $350 US.

The framing top & bottom are 2" x 4" bars, the sides, 3" x 4.31#/ft channel. The guides are leftover steelbushings welded half round to the press plunger plate and ride over the (2) 1"ø bolts (leaf spring bolts from a dump truck).The cylinder rod top (red) is threaded and I used a cap from another portapower jack to connect the cylinder to the frame top by welding.The gap between the bushings and the bolts is approx. 1/16".

Although the pump is double acting, the cylinder isn't, hence the return springs. I've used this little press extensively for the last 5 years for all kinds of forming work, you can see the press brake dies. Using this setup, I have bent 3/8" x 6"bars 90º with no problem.