Twist drill
AssigneeKennametal Inc.
InventorsBernhard W. Borschert, Jerome C. Hanna, Tilo Krieg, Larry R. Meenan, Michael D. Shultz
Life of this patent
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Abstract
A twist drill including a cutting tip having a front flank face, a substantially cylindrical tool body extending rearwardly from the cutting tip, and a shank. The tool body includes a rotational axis therethrough and at least one flute formed on an outer peripheral surface thereof and extending to the front flank face. The at least one flute includes a first helical portion opening to the front flank face and a second helical portion extending from the rear end of the first helical portion toward the rear portion of the tool body. The second helical portion twists in a direction opposite of the first helical portion.
Claims20
A twist drill comprising:
- a cutting tip including a front flank face, a substantially cylindrical tool body extending rearwardly from the cutting tip, and a shank;
- the tool body having a rotational axis therethrough and including at least one flute formed on an outer peripheral surface thereof and extending to the front flank face;
- wherein the at least one flute includes a first helical portion opening to the front flank face and a second helical portion extending from the rear end of the first helical portion and a third helical portion extending from the rear of the second helical portion toward the rear portion of the tool body, wherein the second helical portion twists in a direction opposite of the first helical portion and wherein the third helical portion twists in a direction opposite of the second helical portion.
Dependencies are inferred from the claim text.