Metal brakes and bending machines form folds, creases, or curves in sheet metal or angle, bar, and tube stock. Sheet metal brakes bend flat workpieces by folding them against a beam or pressing them into a die. They are commonly used to crease the edges of large sheets and form boxes, pans, and trays. Angle, bar, and tube benders form curves in metal angle, bar, and tube stock. They are commonly used to bend metal for frames, railings, vehicle roll cages, and electrical conduit or hydraulic lines. Lockformers pass sheet metal through a series of rollers to bend the sheets' edges into lock seams for joining sheets together. They are commonly used to assemble HVAC ducts.