Flex Mandrel Mandrel for especially large or freely adjustable radii. The radius can also be changed during use, i.e. it can be narrowed or widened. The middle radius is shown with a marking. Min. radius: 75 mm Max. radius: 165 mm. All bending mandrels and stoppers are designed for tube diameters of 12 or 13 mm and 16 mm. The necessary guidance is always aligned downwards.   Manual