- The fundamental Principle of the Magnetic Bending Machine is that it uses electromagnetic, rather than mechanical, clamping system. The machine consists of a long electromagnet with a steel clamp bar located above it. The sheet metal is clamped between the two by an electromagnet capable of clamping with a force range of between 3-10 tons. Rotating the bending beam then forms the bend. The sheet is bent around the front edge of the clamping bar. They have application in many ways with four various sets clamping bars.