Abstract: A cutting tool, such as a turning tool, includes a clamping holder with a recess in one of its surfaces, a cutting bit insertable into the recess, and a clamping shoe secured to the clamping holder by a clamping bolt. The clamping shoe has a projecting member engageable within a depression located in the surface of the cutting bit for securing the cutting bit in the recess of the clamping holder. The depression is defined in the surface of the cutting bit by a closed line formed in part by convexly curved first lines and by second lines interconnecting the ends of the first lines. The depression, as viewed in plan, has an oblong or star-shaped configuration. The lines defining such configuration can be convex, concave or rectilinear. The surface of the depression within the closed line is formed by a radius centered at points located outwardly from the surface of the cutting bit containing the depression. Accordingly, the length of the radius is greater than the depth of the depression.