Abstract: The present invention relates to an expandable shaft (1) for insertion into a core, the expandable shaft have a longitudinal extension and comprising: a profile (4), which extends in the longitudinal direction of the shaft, the profile comprising a plurality of longitudinal grooves; inflatable and expandable chambers which are adapted to be arranged in the grooves; gripping means (3) which are arranged in connection to the expandable chambers, the gripping means being adapted to radial movement between a first position and a second position in view of an expansion of the inflatable and expandable chambers so that the gripping means (3) are movable in a radial direction between a first position and a second position depending on an expansion of the expandable chambers wherein an outer cylindrical tube is arranged outside the profile (4), the outer cylindrical tube comprising a plurality of openings, and wherein the gripping means (3) are aligned with the openings of the tube so that the gripping means can p