A twist drill and an exchangeable head for a twist drill, the twist drill extending along a central axis of rotation and having a front end formed as a drill point with two cutting edges and at least two clearance surfaces. Two helical chip flutes conduct chips away from the cutting edges. Each cutting edge extends in a transition between the clearance surfaces. One of the chip flutes extends from an inner position adjacent to the central axis to a peripheral envelope surface and has a main portion closest to the peripheral envelope surface. Each chip flute is delimited by a side surface including a main rake face, which extends rearward from the main portion of the cutting edge. The cutting edges are contained in an imaginary conical surface, such that the twist drill is operable to generate a bottom profile having the shape of an inverted cone.

One aspect of the invention provides a cutting tool used for peripheral cutting operations, comprising: a plurality of peripheral cutting edges, and a plurality of flutes disposed between the peripheral cutting edges, wherein each of the flutes includes at least one surface, and at least one depression recessed into the at least one flute surface, wherein each of the depressions defines a depression interior configured to trap cooling liquid during operation of the cutting tool, and wherein at least one of the depressions is dimensioned and disposed to enhance heat dissipation at least one of the peripheral cutting edges.

A long twist drill includes a shank and a drill body having a drill tip (16). The twist drill has a length L and an outer diameter D, and has a cemented carbide or high speed steel substrate and a coating of at least one layer. The quota L/D is at least 16. The twist drill has two cutting segments at the tip and two flutes chip. The twist drill is provided with holes for fluid opening in the tip. The twist drill has an axial web thinning angle GAA, which is 40 to 50°. The twist drill further has a web that back tapers such that a web diameter gets smaller in a direction away from the tip towards the shank within an axial distance.

A long twist drill includes a shank and a drill body having a drill tip (16). The twist drill has a length L and an outer diameter D, and has a cemented carbide or high speed steel substrate and a coating of at least one layer. The quota L/D is at least 16. The twist drill has two cutting segments at the tip and two flutes chip. The twist drill is provided with holes for fluid opening in the tip. The twist drill has an axial web thinning angle GAA, which is 40 to 50°. The twist drill further has a web that back tapers such that a web diameter gets smaller in a direction away from the tip towards the shank within an axial distance.

An insert holder includes a cutting portion and a shank portion. The insert holder further includes a cavity which includes a cavity chamber and a plurality of cavity through recesses which serve to reduce the weight of the insert holder. The plurality of cavity through recesses open out to the cavity chamber and to the periphery of the shank portion. A cutting tool is provided having a cutting insert releasably attached to the insert holder.

A cutting tool part includes a cutting portion. The cutting tool part further includes a plurality of guide pads projecting radially outwards from the cutting portion. At least the cutting portion and the plurality of guide pads are made through additive manufacturing, the plurality of guide pads being integrally formed with the cutting portion in a unitary one-piece construction. A rotary cutting tool is provided having a cutting insert releasably attached to the cutting tool part.

The outer peripheral surface is provided with a first margin contiguous to each of the cutting edge and the flank face, and a second margin that is located on the rear side with respect to the first margin in a rotation direction and that is separated from each of the flank face and the thinning face. An outer peripheral portion of the first margin and an outer peripheral portion of the second margin have respective back tapers having the same angle. In a direction parallel to the axial line, a distance between a front end of the first margin and a front end of the second margin is more than or equal to 3 mm and less than or equal to 5 mm.

The outer peripheral surface is provided with a first margin contiguous to each of the cutting edge and the flank face, and a second margin that is located on the rear side with respect to the first margin in a rotation direction and that is separated from each of the flank face and the thinning face. An outer peripheral portion of the first margin and an outer peripheral portion of the second margin have respective back tapers having the same angle. In a direction parallel to the axial line, a distance between a front end of the first margin and a front end of the second margin is more than or equal to 3 mm and less than or equal to 5 mm.

The invention relates to a method for producing a dental drill that has a shank (1) and a work section. The shank contains a centrally arranged, continuous first channel (3). The work section contains one or more continuous, spiral-shaped further channels (4a, 4b). The first channel and the further channels open into a common chamber (5) connecting the shank and the work section. The shank is sintered with the work section in order to form a one-piece, sintered component that encloses the chamber connecting the shank and the work section.

The invention relates to a method for producing a dental drill that has a shank (1) and a work section. The shank contains a centrally arranged, continuous first channel (3). The work section contains one or more continuous, spiral-shaped further channels (4a, 4b). The first channel and the further channels open into a common chamber (5) connecting the shank and the work section. The shank is sintered with the work section in order to form a one-piece, sintered component that encloses the chamber connecting the shank and the work section.