A drill bit comprises a cutter rod (1) having a tip with two cutting blades (5, 5 ') located on a main plane (C-C), and the cutting blade (5, 5 ') having a short central cutting edge oriented on a common second plane (E-E). The blade forms a point-shaped central cutting edge for entering the workpiece and from this aligning the drill bit. On the cutter rod, two chip removing slots (6, 6 ') are arranged, and the chip removing slots (6, 6 ') extend from the tip to the end. On any section along the knife bar, the chip removal groove is located in a position opposite to each other in radial direction on the pipe plane, and the pipe plane extends 90° with the common blade belt plane (F-F) of the two blade belts on both sides of the pipe, and the knife rod has the maximum rigidity in this plane. The orientation of the second plane (E-E) of the central cutting edge is approximately 90° from the main rigidity direction (F-F) of the belt plane or the bottom of the tool.
A drill bit that, in drilling concrete, etc., mitigates sudden changes in drilling status, stabilizes drilling operations, and does not reduce drilling efficiency even when large chips are produced.
It is roughly the cutting edge of radial configuration, with at least two main cutting edge, and the distribution in circumferential direction described main cutting blade and the main cutting edge between, at least two vice cutting blade, described the main cutting blade have as its main cutting edge and cutting edge within the main cutting edge side is located in the center of rotation, the rotation of the outer side is located at the cutting edge of the outside part of the trajectory.
The secondary cutting edge has a secondary cutting edge as its cutting edge. The inner end of the secondary cutting edge is located at a part deviating from the rotation center to the outer diameter side, and the outer end is located at a position deviating from the outer edge of the rotation track of the cutting edge to the rotation center side.
The utility model relates to a drill having a plurality of cutting edges arranged at the front end of a drill bit and an axial drill body with a shank arranged on one side of the base end of the cutting edge;
The cutting edge is provided with a cutting edge formed by protruding the front end side of the joint edge between the cutting surface and the rear clearance surface. The cutting edge is arranged in a roughly radial shape from the lateral outside diameter side of the rotation center of the drill bit;
The cutting edge is characterized in that the cutting edge has at least two principal cutting edges and at least two secondary cutting edges arranged between the principal cutting edge and the principal cutting edge in the circumferential direction.
Described main cutting blade has as its cutting edge of the main cutting edge, described the main cutting edge within the terminal is located in the center of rotation, the rotation of the outer side is located at the cutting edge of the outside part of the trajectory, vice cutting blade is described as a cutting edge cutting edge, described vice cutting edge within the client is located in the part of the lateral deviation from the center of rotation to diameter, is located in the outer end from the rotation of the cutting blade is path to the center of rotation to the outer side of the location of the deviation.