Abstract: A device for fastening includes a threaded rod, a nut that can be screwed on the rod and elements for locking the nut in rotation in relation to the threaded rod including an intermediary ring mounted between a skirt of the nut and an end of the threaded rod, this ring including rotational coupling elements with the end of the threaded rod and rotational coupling elements with the skirt of the nut. The nut is elastically deformable to tightening during the screwing on the threaded rod.