Abstract: A method for cold expansion of a hole formed in a work piece. The method comprises providing a body comprising at least a cylindrically shaped part having an inner hole in axial direction of the body. The body further comprises along its circumferential direction a plurality of members which are movable in radial direction of the body, such that the outer diameter of the cylindrical part of the body can be changed.

Abstract: A method for cold expansion of a hole formed in a work piece. The method comprises providing a body comprising at least a cylindrically shaped part having an inner hole in axial direction of the body. The body further comprises along its circumferential direction a plurality of members which are movable in radial direction of the body, such that the outer diameter of the cylindrical part of the body can be changed.

Abstract: A tool (10) for cold expansion of holes comprises a body (14) which has at least a cylindrically shaped part (16) having an inner hole (24) in axial direction of the body (14). The body (14) comprises along the circumferential direction a plurality of members (18, 18a, 18b, 18c) which are movable in radial direction of the body (14), such that the outer diameter of the cylindrically shaped part (16) of the body (14) can be changed. Furthermore a core (26, 26c) is provided which is insertable into the inner hole (24), wherein at least one of the core (26, 26c) and the inner hole (24) comprises a portion (28) of changing diameter and the inner hole (24) and the core (26, 26c) get into contact with each other upon insertion of the core, such that in dependency of the depth of the insertion of the core (26, 26c) into the inner hole (24) in axial direction the members (18, 18a, 18b, 18c) move radially outwardly and the outer diameter of the cylindrically shaped part (16) of the body (14) increases.