Adapter for holding a tool in a collet chuck

An adapter for holding a tool in a collet chuck, the adapter having an external taper to accommodate the adapter in the collet chuck, wherein the adapter has a thread for fastening of the tool, wherein a plurality of shape-mated elements for preventing rotation of the adapter during fastening of the tool is arranged on an outer surface of the external taper, wherein the shape-mated elements are arranged at or near a midline of the external taper such that conical portions of the outer surface of the external taper run above and below the shape-mated elements for contact on a corresponding internal taper in a chuck body of the collet chuck, wherein the shape-mated elements are designed as key surfaces distributed over the outer surface of the external taper, and wherein a distribution channel running at a level of the key surfaces is arranged on the outer surface of the external taper.

A combination of a collet chuck and an adapter for coupling a tool to the collet chuck, wherein

• the collet chuck comprises a chuck body with an internal taper;
• and
• the adapter comprises an external taper to accommodate the adapter in the collet chuck, an internal thread for fastening of the tool, and a plurality of shape-mated elements for preventing rotation of the adapter during fastening of the tool, the plurality of shape-mated elements radially spaced from the internal thread and arranged on an outer surface of the external taper with the shape-mated elements arranged at or near a midline of the external taper such that conical portions of the outer surface of the external taper run above and below the shape-mated elements for contact on the internal taper in the chuck body of the collet chuck.