Abstract: Backing and clamping chuck jaw part (110, 120), respectively, arranged to engage with each other such that respective contact surfaces (113, 123) a rearranged to come into contact with each other so as to together form a chuck jaw (100) for a chuck (10). The invention is characterized in that the backing chuck jaw part is manufactured from a harder metal material than a metal material from which the clamping chuck jaw part is manufactured, in that a the backing chuck jaw part comprises a convex structure (126), and in that the convex structure is arranged to engage with a corresponding concave structure (116) of the clamping chuck jaw part so that the said concave structure is permanently deformed as a result of an engagement between said structures resulting from the chuck jaw parts first being arranged in a contacting orientation and thereafter being pressed together into an engagement orientation, in which contact is established between said contact surfaces.