Abstract: There is disclosed an improved cutting tool having a body provided with a threaded borehole, a clamping bolt and a recess, and which is provided with a supporting surface and at least one lateral supporting surface for supporting an indexable cutting insert. The insert is provided with a center hole for receiving the clamping bolt which has a rotationally symmetrical shaped portion for engaging the center hole thereof. The upper end of the clamping bolt has the form approximately of a clipped ball and the lower end is screwable into the threaded borehole of the tool body with the center portion thereof supported on the tool body; the borehole of the tool body being provided with two coaxial upper and lower cylindrical sections of different diameters extending perpendicular to the surface supporting the cutting insert.