Abstract: A bending machine for bending longitudinally elongated channel-shaped sheet metal members according to the present invention consists of a frame and a die set including a female die assembly and a male die assembly and drive means for driving the die set to and fro between an open and closed position. The female die assembly consists of two members, one of which is held stationary relative to the frame and the other of which is movable relative to the first for movement towards and away from the male die element. The first member of the female die assembly serves to clamp the channel-shaped member with respect to the male die element and the second member of the female die assembly serves to form corrugations in the elongated channel-shaped members.