The tool has a cylindrical sleeve (35) defining a curved path. The support frame (39) for the pivot axis (47) of the bending press (41,53) can fit onto the exterior face of the rod (17) in opposition to a support section of the frame which engages the inner face of the rod. The cylindrical curvature path axis is parallel to the upper surface of the cement (12). The pivot axis is parallel to the surface axis. The height stop (57) is connected to the curvature path.
