Patent ID: 7226254

Claim:
A rod-shaped tool of sintered material for machining a workpiece, with a rod centre axis, a shank region and a chip chamber region adjoining the shank region in the direction of the rod centre axis; wherein the tool has, in the chip chamber region, at least one chip chamber at the outer side and encircling the rod centre axis and, there is no chip chamber in the shank region; wherein the chip chamber has a minimum spacing from the rod centre axis; characterised in that the tool has a closed centre recess which is material-free in the region of the rod centre axis, extends over the shank region and as far as into the chip chamber region, and the closed centre recess has a non-circular cross-section in the chip chamber region and, in the chip chamber region ( 5 ), has a maximum spacing from the rod centre axis ( 1 ) which is at least as large as the minimum spacing.