MEKATRONICSEZ-PRESS Sr. This one-of-a-kind book press is the prototype of the production 1,500 lb. production model. Made of steel and aluminum, it consists of a platen, suspended by constant force springs, counterbalanced to “float” in midair, so that a few ounces of force will move it in either direction. When pushed in contact with books to be pressed, the platen is locked to the posts. Depending on the desired pressing force, two to four effortless quarter-turns of a ratchet wrench can produce a pressing force of up to 3,000 lbs.