Abstract

1. A tool holder for drilling machines, drilling devices as well as drills and drill sets.2. The tool holder, which is developed as a multi-jaw chuck, has a cylindrical bore 326 into which, with maximum opening of the holder, the jaws 322 engage, or the driver of each jaw has an end surface 416 which faces the hollow space of the holder and is interrupted by an axially extending rib 320.The drilling device has a tool holder developed as multi-jaw chuck and a drill whose chucking shank is guided axially in the hollow space of the holder and has grooves for the engagement of radially inner parts of the jaws of the multi-jaw chuck.In its chucking shank the drill has axially extending grooves for the engagement of the jaws of a multi-jaw chuck, within the bottom of which grooves, or at least in one of them, there is a trough which terminates at a distance from the rear end surface and is connected with said end surface by an introduction groove whose cross section is smaller than the cross section of the groove.The drill set consists of drills having chucking shanks of different thickness. The thicker chucking shanks have at least two axially extending grooves for the engagement of the jaws and the thinner shanks have resting surfaces 416, not coaxial to their axis, for the resting against the jaws 322 of a multi-jaw chuck.3. FIG. 6.