Step drill

1. A step drill comprising a shaft section extending along a longitudinal axis of the step drill and a cutting section with a cutting tip, the cutting section having a chip-breaking geometry comprising a concavely curved surface configured such that ribbon chips are broken on the concavely curved surface during rotation of the step drill, wherein the chip-breaking geometry is disposed on a reaming step of the step drill, wherein the chip-breaking geometry comprises a depression in a surface of a flute, and wherein the depression has an arcuate contour when viewed from the cutting tip in a plan view of the step drill.

2. The step drill according to claim 1 , wherein the chip-breaking geometry further comprises at least one flat surface.

3. The step drill according to claim 1 , wherein the concavely curved surface comprises a plurality of curved sections.

4. The step drill according to claim 3 , wherein at least two of the plurality of curved sections have a different radius of curvature.

5. The step drill according to claim 1 , wherein the step drill has a plurality of flutes, each flute having the chip-breaking geometry.

6. The step drill according to claim 1 , wherein the chip-breaking geometry is spaced apart from the cutting tip in the longitudinal direction of the step drill.

7. The step drill according to claim 1 , wherein the flute extends helically along a longitudinal direction of the step drill, and wherein, when viewing the step drill from the side, the depression extends along a helical outer edge of the flute.

8. The step drill according to claim 1 , wherein the depression has a flat section, which is adjoined by the concavely curved surface.

9. The step drill according to claim 1 , wherein the chip-breaking geometry extends beyond the reaming step of the step drill.