Drill for chip removing machining
A drill for chip removing machining, including a front tip including at least one cutting edge and a chip flute. The chip flute is countersunk in an envelope surface of a body of the drill and extends rearwardly from the cutting edge. The chip flute is generally defined by a cross-section-wise concavely vaulted surface located between first and second longitudinal borders, the first longitudinal border extending from an area of a peripheral end of the cutting edge. The chip flute is deeper in an area of the first longitudinal border than in an area of the second longitudinal border such that a curve defining the cross-sectional shape of the flute surface has a radius of curvature that is smallest in the vicinity of the first longitudinal border and that increases towards the second longitudinal border. The flute surface transforms into a planar chip surface, which in turn transforms into the cutting edge.
1. A drill for chip removing machining, comprising:
a front tip including at least one cutting edge and a chip flute, the chip flute being countersunk in an envelope surface of a body of the drill and extending rearwardly from the cutting edge, the chip flute being generally defined by a cross-section-wise concavely vaulted surface located between first and second longitudinal borders, the first longitudinal border extending from an area of a peripheral end of the cutting edge,
wherein the chip flute is deeper in an area of the first longitudinal border than in an area of the second longitudinal border such that a curve defining the cross-sectional shape of the flute surface has a radius of curvature that is smallest in the vicinity of the first longitudinal border and that increases towards the second longitudinal border, and
wherein the flute surface transforms into a planar chip surface, which in turn transforms into the cutting edge.
2. The drill according to claim 1 , wherein the flute surface adjacent the first longitudinal border and the envelope surface of the drill body form an angle (α)≧90°.
3. The drill according to claim 2 , wherein the angle (α)≦120°.
4. The drill according to claim 1 , wherein the chip surface extends in a plane that is parallel with a center axis of the drill body.
5. The drill according to claim 2 , wherein the chip surface extends in a plane that is parallel with a center axis of the drill body.
6. The drill according to claim 3 , wherein the chip surface extends in a plane that is parallel with a center axis of the drill body.
7. The drill according to claim 1 , wherein the chip surface extends in a plane forming an acute angle (β)≦25° with a center axis of the drill body.
8. The drill according to claim 7 , wherein 5°≦(β)≦15°.
9. The drill according to claim 2 , wherein the chip surface extends in a plane forming an acute angle (β)≦25° with a center axis of the drill body.
10. The drill according to claim 9 , wherein 5°≦(β)≦15°.
11. The drill according to claim 3 , wherein the chip surface extends in a plane forming an acute angle (β)≦25° with a center axis of the drill body.
12. The drill according to claim 11 , wherein 5°≦(β)≦15°.