The present invention relates to a device for fastening two elements to one another, comprising a rod-like member having opposite ends which are aligned on a common longitudinal axis (X-X) and a threaded portion formed in the region of a first end. A characteristic of the rod-like member is that it comprises a tapered portion formed in the external wall of the rod-like member, the tapered portion having the vertex of its taper facing towards the threaded portion and a taper angle (α), measured relative to the longitudinal axis (X-X), that is within a range variable between 2° and 6°.