Twist drill
AssigneeWalter AG
InventorsSiegfried Rogalla, Stefan Thoma
Life of this patent
Estimating the term…
Abstract
A twist drill has a shaft and a flute portion, which extends between a drill tip and the shaft and has at least two flutes, which run helically around it at an angle of twist, are separated from one another by two webs and have a land extending between the flutes on the circumference of the flute portion. In order to provide a twist drill that has the features mentioned at the beginning, has better lubrication of the round bevels, less wear, improved guidance and improved concentricity, at least two round bevels that are spaced apart from one another are provided on each land and extend on the land at an angle of inclination in relation to the drill axis that is greater than the angle of twist but less than 90°.
Claims15
A twist drill comprising a shank and a flute portion which extends between a drill tip and the shank and has at least two flutes which peripherally extend helically at a twist angle and which are separated from each other by two webs and have a land extending at a periphery of the flute portion between the flutes,
- wherein provided on each land are at least two respective mutually spaced margins which extend on the land at an angle of inclination relative to a drill axis, that is larger than the twist angle but less than 90°,
- wherein the twist angle and the angle of inclination are measured from the drill axis in the same direction, and
- wherein the diameter of the flute portion, defined by the margins, starting from the drill tip, continuously narrows within a distance (A) from the drill tip towards the shank.
A twist drill, comprising:
- a shank;
- and
- a flute portion,
- wherein the flute portion extends between a drill tip and the shank and has at least two flutes, which peripherally extend helically at a twist angle and which are separated from each other by two webs and have a land extending at a periphery of the flute portion between the flutes,
- wherein each land includes at least two respective mutually spaced margins that extend on the land at an angle of inclination relative to a drill axis that is larger than the twist angle but less than 90°,
- wherein the twist angle and the angle of inclination are measured from the drill axis in the same direction, and
- wherein the diameter of the flute portion, defined by the margins, starting from the drill tip, continuously narrows within a distance (A) from the drill tip towards the shank.
Dependencies are inferred from the claim text.