Drill Bits Convenient And Reliable

In the case of a drilling operation for concrete or the like, it is possible to alleviate the sudden change of the drilling state and to stabilize the drilling operation, and the drilling efficiency is not reduced even when the chip is produced.

And a blade portion having a substantially radially arranged cutting edge portion having at least two main cutting edge portions and at least two cutting portions between the main cutting edge portion and the main cutting edge portion in the circumferential direction And the main cutting edge includes a main cutting edge as a cutting edge, the inner end of the main cutting edge is located at the center of rotation, and the outer end thereof is located at the outer edge of the rotation locus of the cutting edge.

Wherein the secondary cutting edge portion has a secondary cutting edge as a cutting edge whose outer end is located at a position offset from the rotation center toward the outer diameter side and the outer end thereof is located outside the rotation locus of the cutting edge portion from the rotation center side The position of the edge.

A drill bit having a plurality of cutting edges disposed at the front end of the drill bit and a shaft-shaped drill body provided on the proximal end side of the cutting blade portion and having a shank formed at the base end portion thereof,

Wherein the cutting edge portion has a cutting edge formed by protruding toward the distal end side from the joining edge of the cutting surface and the back surface, the cutting edge being arranged substantially radially from the side of the rotational center of the drill,

Wherein the cutting edge portion has at least two main cutting edges and a main cutting edge portion arranged in the circumferential direction and a main cutting portion which is arranged in the circumferential direction Between the blade portions, at least two secondary cutting edges;

Wherein the main cutting edge has a main cutting edge as a cutting edge, the inner end of the main cutting edge is located at the center of rotation, and the outer end is located at the outer edge of the rotation locus of the cutting edge portion, And the outer end of the secondary cutting edge is located at a position deviated from the rotation center toward the outer diameter side and the outer end is located at a position deviated from the outer edge of the rotation locus of the cutting edge portion toward the rotation center side.

Applicable to the installation and dismantling of various drill bits. Installation and removal of convenient and reliable.

⒈ drill installation

Slowly put the drill box body, the drill box box of the four legs corresponding to the drill into the four holes, according to the drill bit size selection of the corresponding drill box core board, put the drill box core board into the drill box body and then Install the drill groove corresponding to the tip of the drill box core plate, the drill bit into the drill box, the drill card is placed on the turntable heart. And then turn on the drill pipe nut.

⒉ drill demolition

Lifting the drill pipe (with drill bit), the drill box, such as ① bar requirements and the turntable connection, lifting the drill pipe slowly to the drill groove and the core of the core box corresponding to the core, the drill bit stuck in the drill box, ,drill.