A clamping member (1; 101; 201; 301), for clamping an hexalobular recess screw, for example an osteosynthesis screw, the clamping member (1-301) comprising six convex lobes and six concave lobes alternately distributed about a central axis (X1-X301) so that each concave lobe connects two consecutive convex lobes about the central axis (X1-X301), the clamping member (1; 101; 201; 301) being characterized in that : i) the convex lobes comprise: - at least three cylindrical convex lobes (2; 102; 202; 302), each cylindrical convex lobe (2-302) being significantly defined by a respective cylinder portion having an axis (X2-X302) substantially parallel to the central axis (X1-X301), and - at least two conical convex lobes (202.1; 302.1), each conical convex lobe (202.1; 302.1) being significantly defined by a respective cone portion having an axis substantially parallel to the central axis (X1-X301), two respective conical convex lobes (202.1; 302.1) being separated by at least one cylindrical convex lobe (202; 302), and/or in that : ii) the concave lobes comprise: - at least three cylindrical concave lobes (4; 104; 204; 304), each cylindrical concave lobe (4-304) being significantly defined by a respective cylinder portion having an axis (X4-X304) substantially parallel to the central axis (X1-X301), and - at least two conical concave lobes (4.1; 104.1), each conical concave lobe (4.1; 104.1) being significantly defined by a respective cone portion having an axis (X4.1; X104.1) substantially parallel to the central axis (X1-X301), two respective conical concave lobes (4.1; 104.1) being separated by at least one cylindrical concave lobe (4-104). i) the convex lobes comprise: - at least three cylindrical convex lobes (2; 102; 202; 302), each cylindrical convex lobe (2-302) being significantly defined by a respective cylinder portion having an axis (X2-X302) substantially parallel to the central axis (X1-X301), and - at least two conical convex lobes (202.1; 302.1), each conical convex lobe (202.1; 302.1) being significantly defined by a respective cone portion having an axis substantially parallel to the central axis (X1-X301), two respective conical convex lobes (202.1; 302.1) being separated by at least one cylindrical convex lobe (202; 302), - at least three cylindrical convex lobes (2; 102; 202; 302), each cylindrical convex lobe (2-302) being significantly defined by a respective cylinder portion having an axis (X2-X302) substantially parallel to the central axis (X1-X301), and - at least two conical convex lobes (202.1; 302.1), each conical convex lobe (202.1; 302.1) being significantly defined by a respective cone portion having an axis substantially parallel to the central axis (X1-X301), two respective conical convex lobes (202.1; 302.1) being separated by at least one cylindrical convex lobe (202; 302), - at least three cylindrical concave lobes (4; 104; 204; 304), each cylindrical concave lobe (4-304) being significantly defined by a respective cylinder portion having an axis (X4-X304) substantially parallel to the central axis (X1-X301), and - at least two conical concave lobes (4.1; 104.1), each conical concave lobe (4.1; 104.1) being significantly defined by a respective cone portion having an axis (X4.1; X104.1) substantially parallel to the central axis (X1-X301), two respective conical concave lobes (4.1; 104.1) being separated by at least one cylindrical concave lobe (4-104). <EOS>