OK... I've preached it for years and years, and have witnessed it a couple of times first hand...
IF YOU ARE GOING TO BUILD/USE A HYDRUALIC PRESS FOR FORGING, DO NOT CHEAP OUT ON BUILDING IT, AND ESPECIALLY DON'T CHEAP ON ON THE CYLINDER... AT LEAST 5" IN DIAMETER, AND BETTER YET.. 6"!!
Why? LINE PRESSURE! The smaller the cylinder diameter, the higher the required pressure to gain tonnage (how hard it actually presses down). Anything over 2500psi is TOO MUCH! Yes, typical hydraulic lines are rated from 3,000 to 4,500 psi.... but that is best case scenario, and not the torturous use and environment that forging presses sees, along with the spikes in pressure that occur simply by the way a forging press is used.
If you want to roll the dice or play the odds... you should look at this before doing so....
https://www.mfcp.com/our-blog/bid/39...ction-injuries
If you screw around and try to build/use a forging press with a small cylinder...its not gona be IF.... it's gona be WHEN. Nuff Said!