a) A smooth roller of nominal diameter 65 mm and of nominal length 410 mm.
b) A smooth forming board of nominal internal area 270 mm x 500 mm and constructed with a lip of height 5 ± 0,2 mm and of nominal width 10 mm.
c) A bending machine, so constructed that it clamps each end of a test piece and, while oscillating at a constant frequency in the range 125-150 cycles per minute, guides the test piece in such a way that one side is bent at an angle of 90° about a mandrel of radius 15 mm (see Fig.1).