The invention relates to a tool holding device comprising a tool holding body for securing, in a fixed manner, a rotary tool comprising a shaft, provided with a clamping section and a receiving opening for the shall of the tool, a coolant feeding device for pressurized fluid, at least one coolant guiding device for guiding the coolant into a clamped tool shaft. The coolant guiding device is designed as at least one flat groove on an inner side of the receiving opening, joining to the front side on a free end of the tool holding body and directly adjacent to the tool shaft in the surroundings of the tool holding device or a coolant storing chamber and or collecting chamber is provided in the region of the free end of the tool holding body, to which the at least one coolant guiding device joins. The coolant storing chamber and or collecting chamber is connected by means of an annular gap to the surroundings of the tool holder device. The coolant storing chamber and/or collecting chamber and the annular gap are defined at least partially by the work shaft.

The invention is directed to a drill system that better uses the power curve of modern machine tools. The drill system uses IC inserts to perform the major hole diameter cutting, and a central drilling system that cuts the remaining minor diameter portion of the hole, and is configured to see less cutting surface footage, due to its position from the rotating center of the tool. A connection between the drill head and a holder body secures the drill head in a manner to effectively absorb lateral drilling forces. The drill system allows for a large diameter deep hole that remains straight throughout to be drilled at higher speed and lighter feed rates thus offering a more productive tool that takes advantage of the power curves and lower thrust capabilities of modern machine tools.

The rotary tool (2) is in particular designed as a modular drill and extends in an axial direction (4) along an axis of rotation (6). It comprises two coupling parts, namely a carrier (10) and a cutting head (12) that is attached to the carrier (10) so as to be exchangeable. A pin receiving means (20) is provided on the carrier (10), into which pin receiving means a coupling pin (40) of the cutting head (12) is introduced in a clamping manner and so as to be reversibly exchangeable. The pin receiving means (20) and the coupling pin (40) have torque sections (30a,b) and clamping sections (32a,b) that correspond to one another. In order to permit simple production, these clamping and torque sections are oriented parallel to the axis of rotation (6). In addition, in order to prevent pulling-out in an axial direction, stop surfaces (38a,b) are provided on the pin receiving means (20) and on the coupling pin (40), said stop surfaces being effective in an axial direction (4) and corresponding to one another. These stop surfaces preferably extend horizontally and therefore perpendicular to the axis of rotation (6).

A drill bit rotatable about a rotation axis is disclosed. The drill bit has a first drill bit portion configured as a cutting portion and has an annular portion connected at one end to one or more cutting elements and, at another end, a first connection device. The drill bit has a second drill bit portion configured as a drilling shank portion and has a cylindrical drill shaft, which on one end has a second connection device. The first and second connection devices in a connected state form a detachable connection, and a force transmission and torque transmission occur from the drill shaft portion to the cutting portion. The cutting portion has a third connection device, and the drill shaft portion has a fourth connection device. The third and fourth connection devices in a connected state form in an axial direction parallel to the axis a form-fitting connection.