A vertical-edge double-step sawtooth cutter for preparing high-quality holes of composite material and thereof hybrid stack structure, and has three parts which are a major cutting edge region A, a minor cutting edge region B and a shank region C. The minor cutting edge region B comprises a step vertical-edge region D and a sawtooth cutting region E. This has the step structure and the sawtooth structure which is distributed in the first step, has a recutting function at the inlet and a reverse cutting function at the outlet in the direction opposite to the main cutting motion. The cutter has the vertical edge structure distributed in the second step, and the angle of the second step is a negative value, thereby realizing chip breaking and crushing, reducing scratch to the upper-layer composite material and metal hole walls.

A drill body and a drill are disclosed. The drill body has a rotational axis and comprises a central chip flute extending along a periphery of the drill body. A central chip flute cross-section has a centre line extending in a plane extending perpendicularly to the rotational axis, and through the rotational axis. The central chip flute cross-section has a depth, as seen along the centre line, and a width as seen perpendicularly to the centre line. The central chip flute cross-section has a maximum depth Dp within a range of Dp=0.75D/2 to Dp=0.90D/2, and a maximum width W within a range of W=0.75D/2 to W=0.90D/2, and wherein the maximum width W extends symmetrically about the centre line.

A drill body and a drill are disclosed. The drill body has a rotational axis and includes a peripheral chip flute extending along a periphery of the drill body. A peripheral chip flute cross-section has a centre line extending in a plane extending perpendicularly to the rotational axis, and through the rotational axis. The peripheral chip flute cross-section has a radially inner side extending perpendicularly to the centre line, and first and second lateral sides connecting to the radially inner side. The radially inner side has a length L1 within a range of L1=0.95D/4 to L1=1.2D/4. Each of the first and second lateral sides has a length LS1, LS2 within a range of D/4 to 1.3D/4. The first and second lateral sides diverge from each other in a direction radially outwards from the radially inner side.

A drill according to an embodiment includes a bar-shaped drill body extending along a rotation axis, a cutting edge located at a front end of the drill body, and a first flute extending spirally from the cutting edge toward a rear end of the drill body. The first flute includes a first region which is located close to the front end and has a helix angle 1, and a second region which is located closer to the rear end than the first region and has a helix angle 2 smaller than the helix angle 1. The second region includes an elongated protruding part along the first flute.

A drill bit for forming a round hole in a workpiece, includes a cylindrical shank having a longitudinally extending fluted portion with opposed first and second ends, and defining a longitudinal axis about which the shank is rotatable. The fluted portion includes opposed helical flutes formed in the cylindrical surface of the fluted portion of the shank and extending longitudinally along and between the first and second ends of the fluted portion. The helical flutes each define a concave surface intersecting with the cylindrical surface of the shank to form opposed flute edges. The first end of the fluted portion includes a cutting tip intersecting the helical flutes, wherein at least one of the flute edges has a concave cross-section extending from the second end toward the first end of the fluted portion.

A drill bit for drilling into masonry or rock includes a drilling head at its forward end, a clamping shank at its rearward end, and a helical conveying portion extending between the drilling head and the shank. The helical conveying portion includes at least two helically extending flutes separated by at least two helically extending webs. The helical conveying portion has a changeover portion, a pre-changeover portion between the drilling head and the changeover portion, and a post-changeover portion between the changeover portion and the shank. In the pre-changeover portion, the flutes have a pre-changeover pitch, the first web has a first pre-changeover web width , and the second web has a second pre-changeover web width . In the post-changeover portion, the flutes have a post-changeover pitch, the first web has a first post-changeover web width , and the second web has a second post-changeover web width . The post-changeover pitch is greater than the pre-changeover pitch, the first post-changeover web width is less than the first pre-changeover web width , and the second post-changeover web width is greater than the second pre-changeover web width .

A rotary tool may include a body, the body may include a cutting edge and a first groove. The first groove may include a first region having a first helix angle, a second region having a second helix angle, a third region having a third helix angle, a fourth region having a fourth helix angle, and a fifth region having a fifth helix angle. The fourth helix angle and the fifth helix angle may each decrease from a side of a first end toward a second end. A decreasing range of a value of the fourth helix angle of the fourth region may be less than a decreasing range of a value of the fifth helix angle of the fifth region. A length of the fourth region may be greater than a length of the fifth region.

A drill bit including a body, a shank, a cutting head, and an external covering. The body has a first end and a second end. The shank is located at the first end. The cutting head is located at the second end. The external covering is separately formed from the body and is located between the first end and the second end of the body. The external covering includes a sleeve. The sleeve has a sleeve body that radially surrounds a portion of the body and a plurality of flutes helically wrapped around the sleeve body.

The drill has a rake face, a flank face, and an outer circumferential surface. The flank face is continuous to the rake face. The outer circumferential surface is continuous to both the rake face and the flank face. A ridgeline between the rake face and the flank face constitutes a cutting edge. A ridgeline between the rake face and the outer circumferential surface constitutes an outer circumferential end. A groove is provided cyclically in the rake face to extend at an angle relative to an axis of the drill, the angle being larger than a helix angle of the drill. The groove has a depth of more than or equal to 1.5 m.

A method for the laser-based generation of a structure on a rake face of a cutting tool is disclosed, where at least one structure is formed by lines that are generated with a mutual spacing of at most 400 m with a laser beam at least in areas within a predetermined contour on at least one rake face of the cutting tool. A course of the lines forming the structure is oriented with respect to a profile of at least one cutting edge of the at least one rake face.