A drill/driver chuck has a cylindrical member (2) with a central axial bore (4). A plurality of further bores (6) slanted with respect to the axis of the cylindrical member (4). A jaw actuator (10) is coupled to each jaw (8) and moves them within their respective bores (6). The jaw actuator (10) has a conical shape with the walls of the cone having a plurality of slots (12) formed therein to co-operate with each respective jaw (8).