portion 94a of the cam groove 94 by virtue of the rotation of the cam plate 92 relative to the cam roller 96 as heretofore described the left hand end of the first arcuate track portion 94a of the cam groove 94 leads into the bottom end of a second generally radially extending portion 94b of the cam groove 94 and further rotation of the cam plate 92 will cause the cam roller 96 to rise vertically as the second generally radially extending portion 94b of the cam groove 94 moves past the cam roller 96 this vertical rising of the cam roller 96 will cause the second pair of links 58 to rotate in a clockwise direction around the central axis of the central rod 62 thereby causing the central axis of the oscillatable shaft 50 to move clockwise in a circular arc around the central axis of the central rod 62 this clockwise movement of the central axis of the oscillatable shaft 50 will lift the first pair of links 48 so that the point 44c of the hemming tool element 44 will move up and over the top of the now partially folded in flange f of the outer part 0 along a second portion l2 of the path of travel l after the cam roller 96 reaches the uppermost end of the second generally radially extending portion 94b of the cam groove further rotation of the cam plate 92 will cause the cam roller.