The invention relates to a rotatable tool for chip removing machining, of the type that comprises a basic body (1), e.g. a drill shank, and an exchangeable loose top (2). Between these there is a coupling, which includes a male part (12) on the loose top, and a groove (4) in the basic body. By means of a slot (5), two deflectable legs (6) are defined, which form a jaw for receiving and clamping of the male part (12). According to the invention, the maximal width (W) of the jaw upon deflection of the legs (6) is larger than the maximal breadth (B) of a wedge portion (15) included in the male part. Furthermore, the angles of inclination ( alpha , beta ) of flank surfaces (18) on the male part and side surfaces (25) in the groove, are equally large in order to guarantee surface contact between said surfaces, when the legs (6) resiliently are tightened against the male part. <IMAGE>