My hubby, who is now retired, used to have a contract engineering business. He designed and built special machinery for many different companies. He also did modifications and upgrades to already existing machinery to improve function and increase productivity. One of the more heavy duty machines that he recently worked on was a progressive stamp and metal forming machine that made parts for a garage door manufacturer. It had a hydraulic power unit that was powerful enough to break heavy duty structural parts of the machine but it was not properly controlled. He solved the problem by adding multiple limit switches to the die that would stop the hydraulic cylinders from overloading the structure. Although he is now retired, we still have leftovers on some stuff that he used on some of his projects like heavy duty slides and many other hardware supplies.