This is from a post I did some time ago on another form some time ago. I work for a hydraulic company and have spent most of my career designing hydraulic systems for Steel mills and Potash mines. So when I decided to build a press for making damascus it was simply a matter of scrounging up the right parts. Well, it wasn’t to long and a scrap 6-inch cylinder appeared that had 18 inches of good usable tubing for the cylinder barrel and soon after that a 3-inch piece of chrome shafting was available for the cylinder rod. So all that was left to do was to machine all these pieces make the piston and head assembly and supply a few pieces of heavy plate. By the end of summer I had a 6-inch bore, 3-inch rod and a 10-inch stroke hydraulic cylinder that was rated for 5000 PSI. Designing the Press The criteria for the press design: -It had to be rigid so there would be no sideways or twisting movement while pressing, either in the frame or the cylinder -The press had to be capable of withstanding 45 tons of force -The dies had to be rigidly fixed and easily removable -The unit would have to operate on 115 volt single phase power and still be fast enough to get the job done , because I had no access to a larger power supply. -The complete press would be compact and transportable The structure of the press was made from three pieces of 2x2x3/16 HSS steel. The pieces were all welded together and the cylinder mounted to a piece of 1-inch plate. The press measures 50 inches high and is 14 inches wide. I would estimate the press to weight at about 600-800 pounds. The hydraulic power unit I had was from a hose-crimping machine. The pump is a two-stage unit that puts out 3 GPM @ 0 PSI and .6 GPM @ 4700 PSI, using a 1 HP 115-volt electric motor. There was not nearly enough flow to operate the 6-inch bore cylinder fast enough. So a hydraulic circuit was designed using a Regeneration Circuit that I had used many times before on customer applications where you want the cylinder to move very fast until it contacts the work piece and then achieves maximum pressing force. This is how REGENERATION works. The regeneration is accomplished by taking the flow out of the rod end of the cylinder and adding it back into the cap end of the cylinder as the cylinder extends. This means effectively that the cylinder velocity is a function of the cylinder rod, in this case 3 inch diameter. By using some added valving and check valves the cylinder will rapid advance and then be able to achieve maximum pressing force. When the cylinder is advancing toward the steel billet to be pressed it is moving at the same rate as a 12 GPM pump would move it but only using a 3 GPM pump. This increase in flow is dependent upon the rod and piston ratios. At 1200 PSI the remote operated sequence valve is shifted through the pilot line and diverts the rod flow back to the reservoir instead of into the cap end of the cylinder giving full system pressure on the cylinder. When this happens you are already exerting 33,900 pounds of force on the steel billet. As the cylinder continues to compress the billet a maximum pressure of 3200 PSI is reached producing 90,432 pounds of force to squeeze the billet (limited by the relief valve setting on the control valve). To date we have pressed about 200 billets of Damascus steel with the press and it has lived up to the design specifications that I wanted. The press is compact, stable, the dies are easily interchangeable, speed it not a problem. A couple of years ago I modified the press with a larger hydraulic unit because I wanted to make a rolling mill adddition to the press and need a pump with more flow. I have just re designed the power unit and the hydraulic circuit on my forging press. The press has a 6 inch bore cylinder with a 3 inch rod and is operated with a 5 GPM pump and a regeneration circuit for faster speed. The system pressure is set at 2500 psi which gives you 70,000 pounds of force out of the cylinder.