A large force is required to bend stock to an acute angle of one hundred and eighty degrees. Bending apparatus which requires such a large force uses a hydraulic cylinder with an extending ram. An extension of the ram transmits the force to apparatus which bears against the stock and bends it. An acute angle bend presents a problem compared to smaller bends because the force required is large and must be exerted over a long distance. This is difficult to achieve with a cylinder and ram because the long distance requires a long cylinder and ram which are both prone to buckling under such a large force.
While a variety of metal stock benders are known in the art, the ability to bend stock to an acute 180 degree angle has only been provided by Mann et al. U.S. Pat. No. 2,656,872. Mann et al. utilizes a swinging frame which changes the angle and distance of the frame with respect to a forming die. This permits making a large bend by making smaller bends at each location. This apparatus is fairly complex and requires a substantial amount of shop space because of the size of the frame and the size of the arc.