A cutting tool comprising at least one blade arranged at an axial cutting head end of a tool carrier. The tool carrier comprises a chip-removal space that receives material chips removed by the blade. In some embodiments, the blade is adjacent to a chip passage feeding into the chip-removal space, which passage is limited by a radial chip gap partially limited by the blade and from there by a first and second passage surface, the first passage surface a continuation of the chip surface of the blade, the second passage surface running at an angle and widening relative to same, and is closed and limited at least in an axial sub-section facing the cutting head end, all around by a peripheral wall as a third passage surface, wherein at least one coolant channel is formed within the peripheral wall, which is provided to guide coolant to the cutting head end.

A step drill bit includes a body with a plurality of cylindrical steps of increasing diameter from a front end toward a rear end, a flute extending from the front end toward the rear end, and cutting edges at junctions between each step and the flute. A cutting insert with a hardness greater than the hardness of the body is coupled to the front end portion and at least partially defines a cutting head portion. The cutting head portion includes a center cutting tip, a cutting edge extending radially outward from the cutting tip, a rake face extending from the cutting edge toward the rear end portion, a relief face extending from the cutting edge in a circumferential direction opposite a rotational cutting direction of the drill bit, and a chip clearing recess in communication with the flute, with the rake face facing the chip clearing recess.

A cutting section (11) which is connectable to a drill shaft section via a releasable connecting device. The cutting section includes a first open tubular element (14) which is in the form of a first hollow cylinder having a first waved, trapezoidal or zigzag-shaped cross-sectional area, a second closed tubular element (15) which is in the form of a second hollow cylinder having a circular ring-shaped cross-sectional area, and one or more drill segments (16) which are connected to the first open tubular element (14) and to the second closed tubular element (15).

A drill (1) is provided with a body (10) and a head (30). The body (10) is formed of cemented carbide, and the head (30) is formed of PCD. Spiral coolant passages (17, 18) are provided inside the body (10). Oil holes (25, 26) are provided in a body-side joint surface of the body (10). The oil holes (25, 26) are outlets of the coolant passages (17, 18). Coolant passages (37, 38) provided inside the head (30) extend from oil holes (45, 46) provided at a tip (31) toward a rear end (32). A head-side joint surface of the head (30) is joined to the body-side joint surface. Two oil holes are provided in the head-side joint surface. The two oil holes are inlets of the coolant passages (37, 38), and communicate with the oil holes (25, 26) in the body-side joint surface.

A surface coated cutting tool comprises: a tool substrate and a coating layer on a surface of the tool substrate; wherein the coating layer comprises a lower layer, an intermediate layer, and an upper layer, in sequence from the tool substrate toward the surface of the tool. The lower layer comprises an A layer having an average composition represented by formula: (Al.sub.1-xCr.sub.x)N, where x is 0.20 to 0.60; the intermediate layer comprises a B layer having an average composition represented by formula: (Al.sub.1-a-bCr.sub.aSi.sub.b)N, where a is 0.20 to 0.60 and b is 0.01 to 0.20; and the upper layer comprises a C layer having an average composition represented by formula: (Ti.sub.1-α-βSi.sub.αW.sub.β)N where α is 0.01 to 0.20 and β is 0.01 to 0.10; and the upper layer has a repeated variation in W level with an average interval of 1 nm to 100 nm between adjacent local maxima and minima.

According to one implementation, a drill includes: a body without a back taper and a cutting edge part. The body has a flow path of a cutting oil. The flow path is branched to first and second flow paths inside the body. The cutting edge part has a first supply port that supplies the cutting oil toward a workpiece. The first supply port is an outlet of the first flow path. The body has a second supply port that supplies the cutting oil to a clearance between the body and a bush for positioning the body. The second supply port is an outlet of the second flow path. The second flow path has a pressure loss by which the cutting oil is not scattered from the second supply port in a radial direction of the body but exuded from the second supply port.

A drill includes a drill body having a longitudinal axis, a front end, and a frontend portion and at least one flute in the front end portion. A cutting insert is mounted to the drill body in each flute of the at least one flute at the front end of the drill body. The at least one flute includes a plurality of grooves, concave surfaces of adjacent ones of the grooves intersecting to define a ridge separating the grooves.

The invention relates to a drilling tool (50), in particular a dowel hole drill, for the machining of workpieces, in particular workpieces made of wood, plastics, composite materials, comprising a drill shaft (56) with a front surface (60), and to a drill head (58) with at least one cutting edge (66), which is firmly connected, such as soldered, to the drill shaft (56). In order to make available a drilling tool of the type mentioned at the start, which has a broad range of application and is simple to produce, it is provided that the drill head (58) is formed from a composite material with exclusively two layers (38), namely a hard metal layer (36) and an ultra-hard layer (38) which is connected to the hard metal layer (36) and preferably formed from polycrystalline diamond or polycrystalline boron nitride, that the ultra-hard layer (38) is connected directly to the front surface (60) of the drill shaft (56) and that the at least one cutting edge (66) is formed by the ultra-hard layer (38), and a drill bit (62) such as a centering tip is formed by the hard metal layer (36).

A one-piece cutting head for a drill bit includes a main cutting edge that extends between radial extremities of the cutting head. The main cutting edge is disposed between main rake surfaces and main relief surfaces. Each main rake surface includes one or more rake facets, and each main relief surface includes one or more relief facets. Adjacent rake facets and relief facets define a primary transverse edge therebetween that extends away from the main cutting edge. The cutting head further includes a plurality of side cutters that are transverse to the main cutting edge and that propagate from the primary transverse edge to a radial extremity of the cutting head. Each side cutter includes a side cutting edge between a side cutting rake facet and a side cutting relief facet.

A drill may be extended from a first end to a second end and may include a cutting part. The cutting part may include a cutting edge, a flute, an end surface and a connection surface. The flute may be extended from the cutting edge toward the second end. The end surface may be located closer to the second end than the flute. The connection surface may be located between the flute and the end surface. The connection surface may include a first portion, and a second portion located closer to an outer periphery of the cutting part than the first portion. A length in the direction along the rotation axis on the second portion may be smaller than a length in the direction along the rotation axis on the first portion in a side view orthogonal to the rotation axis.