Hydraulic Press
A surplus 3.5" x 6" hydraulic cylinder coupled with a surplus hand pump will give around 20 tons or more.  Pump delivers pressure on both strokes.
The Cylinder is on a carriage that moves left or right on rollerblade wheels.  A bottle with about 20 PSI of air puts pressure on the bottom side of the piston, making it self-retracting.
The business end of the ram accepts various adaptors.  The one shown  takes 3/8" square drive sockets.

The work platform is not adjustable.  I just stack appropriate metal or wood to change the work height.

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