There is a chart on the machine that tells you what the tonnage requirements are for a particular piece of metal. For instance, if you use the rule of 8 X the material thickness for the die opening, you can work ¼” steel plate at 15.4 tons per foot. If you want to brake a 1/8″ sheet, it would require ½ of the 15.4 tons or 7.7 tons.