Abstract: The present invention relates to a step drill bit, characterized in that the step drill bit has a hole processing portion and at least two flutes extending on the hole processing portion, the hole processing portion comprising step sections, each step section and the at least two flutes forming at least two cutting edges distributed in a circumferential direction of the step section, wherein, the at least two cutting edges on at least one of the step sections at least comprise a first cutting edge and a second cutting edge, wherein the first cutting edge and the second cutting edge are respectively constructed in at least two-segment style, and therefore respectively include at least two cutting edge segments, wherein the first cutting edge and the second cutting edge are at least partially different from each other in the structure of their cutting edge segments, or one cutting edge of the first cutting edge and the second cutting edge is formed in one-segment style, while the other cutting edge is formed in

Abstract: The present invention provides a twist drill. A cone portion is provided at a front end of the operating portion, and an exterior surface of the operating portion is provided with a spiral flute for shunting cutting chips. The exterior surface of the cone portion is provided with a plurality of composite cutting blade groups which are sequentially enlarged in diameter from the front end to the rear end of the cone portion. The cone portion is provided with a top blade on the tip. In use, the top blade is used for positioning, and the cutting process is carried out by the top blade and the composite cutting blade groups.

Abstract: The present invention provides a twist drill. A cone portion is provided at a front end of the operating portion, and an exterior surface of the operating portion is provided with a spiral flute for shunting cutting chips. The exterior surface of the cone portion is provided with a plurality of composite cutting blade groups which are sequentially enlarged in diameter from the front end to the rear end of the cone portion. The cone portion is provided with a top blade on the tip. In use, the top blade is used for positioning, and the cutting process is carried out by the top blade and the composite cutting blade groups.

Abstract: The present invention provides a twist drill. A cone portion is provided at a front end of the operating portion, and an exterior surface of the operating portion is provided with a spiral flute for shunting cutting chips. The exterior surface of the cone portion is provided with a plurality of composite cutting blade groups which are sequentially enlarged in diameter from the front end to the rear end of the cone portion. The cone portion is provided with a top blade on the tip. In use, the top blade is used for positioning, and the cutting process is carried out by the top blade and the composite cutting blade groups.

Abstract: The present invention provides a twist drill. A cone portion is provided at a front end of the operating portion, and an exterior surface of the operating portion is provided with a spiral flute for shunting cutting chips. The exterior surface of the cone portion is provided with a plurality of composite cutting blade groups which are sequentially enlarged in diameter from the front end to the rear end of the cone portion. The cone portion is provided with a top blade on the tip. In use, the top blade is used for positioning, and the cutting process is carried out by the top blade and the composite cutting blade groups.

Abstract: The present invention provides a twist drill. A cone portion is provided at a front end of the operating portion, and an exterior surface of the operating portion is provided with a spiral flute for shunting cutting chips. The exterior surface of the cone portion is provided with a plurality of composite cutting blade groups which are sequentially enlarged in diameter from the front end to the rear end of the cone portion. The cone portion is provided with a top blade on the tip. In use, the top blade is used for positioning, and the cutting process is carried out by the top blade and the composite cutting blade groups.

Abstract: The present invention provides a twist drill. A cone portion is provided at a front end of the operating portion, and an exterior surface of the operating portion is provided with a spiral flute for shunting cutting chips. The exterior surface of the cone portion is provided with a plurality of composite cutting blade groups which are sequentially enlarged in diameter from the front end to the rear end of the cone portion. The cone portion is provided with a top blade on the tip. In use, the top blade is used for positioning, and the cutting process is carried out by the top blade and the composite cutting blade groups.

Abstract: An efficient twist drill fir layered drilling comprises a drill bit body, wherein the drill bit body comprises a shank portion and an operation portion; the shank portion is connected with the operation portion; the operation portion has a cutting portion at a front end thereof; a plurality of flutes distributed in parallel and at intervals are symmetrically arranged along a flank surface of the cutting portion; the flutes divide main cutting blades into a plurality of first cutting blades and second cutting blades; and connecting lines of the first cutting blades and the second cutting blades form a step-like structure. During drilling, a drill bit of the twist drill requires a decreased drilling force, produces less cutting heat, is positioned easily and has improved processing efficiency so that a processed circular hole has high precision and few burrs at an edge where the drill bit exits.

Abstract: The present disclosure relates to a rotary burs with variable pitch. The file is made up of a cutter head (1) and a cutter handle (2). The cutter head is connected with the cutter handle. Multiple groups of cutter teeth are distributed on the cutter head. Each group of cutter teeth can be mixed cutter teeth, and can also be a single cutter tooth. The mixed cutter teeth are respectively a group of cutter teeth composed of a large tooth (3), a medium tooth (4) and a fine tooth (5) sequentially arranged, and can also be a group of mixed cutter teeth formed by combining any two of a large tooth, a medium tooth and a fine tooth.

Abstract: A highly efficient, anti-vibration, durable rotating file with variable pitch comprises a cutter head (1) and a cutter handle (2), wherein the cutter head is connected with the cutter handle; multiple groups of cutter teeth are distributed on the cutter head; each group of cutter teeth can be mixed cutter teeth, and can also be a single cutter tooth; and the mixed cutter teeth are respectively a group of cutter teeth composed of a large tooth (3), a medium tooth (4) and a fine tooth (5) sequentially arranged, and can also be a group of mixed cutter teeth formed by combining any two of a large tooth, a medium tooth and a fine tooth.