Abstract: The present invention relates to a drill having an aggressive drill point geometry. The point geometry allows greater stability and feed rates, while decreasing the heat generated at drill point. The present invention is provided by a drill comprising drill body having at least two helical flutes, a pair of cutting surfaces on an end of the drill body, a web formed between the two cutting edges, and a web thinning notch formed on either side of the web. Each notch forms a notch cutting edge having a positive rake angle.

Abstract: A twist drill bit (1) for use in rock has a helical land (7) arranged between a chuck insert end (2) and a tool head (3), and extends helically around a rotational axis (A) extending along a shaft (5). The radially outer surface (8) of the land (7) has its width (x) increasing as it approaches the tool head (3).

Abstract: A rotary tool such as a helix drill and an end mill for example, is manufactured by forming a blank by an extrusion process, and then sintering the blank. During the extrusion, a mixture is passed through a die which provides a cylindrical shape to the outer peripheral surface of the mixture. A plurality of jaws are disposed downstream of the die for conducting the mixture. Each jaw includes a helical ridge for engaging the outer surface of the extrudate to cause a helical groove to be formed therein which constitutes a chip flute in the tool. During the extrusion, the jaws are moved away from the mixture to terminate formation of the chip groove, whereby a shank portion of the tool is formed.

Abstract: A cutting tip having a three-layer laminated structure is provided. The tip is made from a disc-shaped three-layer laminate wherein a second layer consisting of a hard sintered compact of CBN or diamond is sandwiched by a first layer and a third layer consisting of a tool material such as cemented carbide. Prismatic blanks of rectangular cross-section are cut out by cutting the three-layer laminate in strips. Semi-completed tips of a desired shape are obtained by cutting up the prismatic blanks. Desired cutting edges are formed on the semi-completed tips to produce completed tips. Because prismatic blanks are obtained from a three-layer laminate and semi-completed tips are cut out from the prismatic blanks like this, the semi-completed tips can be obtained in large numbers, yield is high, and the manufacturing cost of the tip can be reduced.

Abstract: There is now provided a twist drill having an elongate body at a first end, a shank at a second and opposite end, the elongate body and the shank sharing a common axis, at least one face on the elongate body at an end opposite the shank, wherein the at least one face defines a corresponding flute extending along the elongate body toward the shank, at least one flank on an end of the elongate body at an end opposite the shank, and a cutting edge at a juncture of the at least one face and the at least one flank, and the like tools, having a sintered cemented carbide body, and the use thereof in material removing and dislodging tools.

Abstract: A twist drill or rotary cutting device, in particular a drill, comprising a tool head or cutting insert consisting of a hard cutting material and a tool shaft which clamps the tool head between two clamp extensions that project axially from said tool shaft in such a way that the tool head is interchangeable. In the fixed position, the interconnected clamping surfaces of the tool head and the clamping extensions of the tool shaft lie on the surface of a truncated cone shaped fixing peg running coaxially with the longitudinal axis of the tool shaft. The fixing peg tapers in the insertion direction, facing the chuck end of the tool shaft.

Abstract: A precision drill bit comprises an elongated body having a stepped centering tip at one end and an engagement shank at the opposite end. A first portion of the bit adjacent the tip has an outer diameter that is less than the outer diameter of a second portion of the bit. At least one cutting flute extends along the length of the bit and exhibits a helix angle of about 38° at the tip. The helix angle decreases to an angle of about 15° at the end of the flute run-out. The helix angle changes progressively and substantially linearly over a number of segments along the length of the drill bit.

Abstract: A drill comprises a shaft with chip conveying flutes and a drill head at its forward end with at least two cutting inserts. Each cutting insert is provided with at least one cutting edge which is delimited between a chipbreaking surface and first relief surface and which includes an outer straight edge. In the proximity of the center axis of the shaft, a curved cutting edge section is provided, to which there is connected an adjacent enforcement bevel. The cutting edge is in direct proximity to a center axis, and is terminated by a chisel edge between the cutting inserts to serve as a centering core portion. The curved cutting edge section is inwardly followed by a primary straight portion without an adjacent enforcement bevel in a direction that is oriented at an angle of between approximately 40-50° in relation to a horizontal line that extends through the center axis of the drill.

Abstract: Coolant delivery channels are cut into the external cylindrical side walls of a cutting tool to direct coolant into the cutting flutes of the tool. Coolant delivered through the chuck of a rotary power tool will be conveyed by the channels into the flutes adjacent the cutting edges to provide optimum cooling of the cutting zone.

Abstract: A drill bit capable of axial cutting as well as side cutting, having a generally cylindrical elongate body with a bit diameter, includes a frontmost drilling end for axial cutting, a cutting section extending from the drilling end for side cutting, and a shank extending from the cutting section. The cutting section is helically cut at a helix angle of substantially 15°±2° to form one pair of diametrically opposite helical flutes whose outermost edges are sharpened to form respective cutting edges, arranged around a solid central core whose diameter is substantially directly proportional to the bit diameter. The length of the cutting edges in the axial direction of the drill bit body is calculated according to the formula: Cutting Edge=Bit Diameter×&pgr;×Cc/Tan (Helix Angle), Cc being a constant in a range from 0.85 to 0.90.

Abstract: The invention concerns a hard-metal cutting tip for use on a drill, particularly on a rock or concrete drill, including a drill point (3) extending through an axis of rotation of the drill, primary cutting edges (6) that slope downwardly on both sides, each composed of a primary land (4) and a primary flank (5), the primary flank (5) forming at the primary cutting edge (6) a primary lip clearance angle (14) with a plane perpendicular to the axis of rotation. To provide a hard-metal cutting tip that possesses high cutting, feed, bending and breaking strength and wear resistance, especially at its outer regions subjected to high peripheral speeds, the hard-metal cutting tip is realized such that the primary lip clearance angle (14) formed at the primary cutting edge (6) decreases with increasing distance from the drill point (3).

Abstract: A dual rake twist drill bit for drilling holes in articles made of abrasive materials, such as fiberglass-filled printed circuit boards, which relatively quickly dull bits, has a conical point and a short front cutting portion in which is formed spiraled flutes having cutting lips which are inclined to the axis of the bit at a relatively small helix angle or rake in the range of about 3 degrees to 10 degrees, and a longer rear portion in which the flutes and cutting lips have a larger rake of about 33 degrees. The dual rake bit has substantially greater wear resistance than single rake bits. In a modification of the dual rake bit, the central web portion thereof has a front longitudinal portion which is relatively acutely tapered, and a rear portion which is relatively modestly tapered, the dual tapered construction increasing resistance of the bit to breaking.

Abstract: In order to improve durability, machining stability, machining accuracy, etc. of a throwaway cutting tool in which a cutting head having a cutting edge is detachably mounted to the tip of a tool body using a clamping tool so that its function can be regenerated by replacing the cutting head, protrusions 8, 16 having their height gradually increasing and recesses 9, 15 having their depth gradually increasing from the center toward outer periphery of the tool are formed alternately with each other in a radial arrangement on the front surface of the tool body 2 and a support surface of the cutting head 3, which is formed by sintering, respectively. The protrusions and recesses, which are provided so that their positions correspond to each other, are conically engaged, thereby centering the cutting head and preventing its movement.

Abstract: There is now provided a twist drill and a method for producing a twist drill which method includes forming a flute of a twist drill. The drill has drill material and a tip portion with a cutting lip. The drill has a land structure and a flute to remove chip residue. The land structure has a flute wall and a cutting edge structure that is disposed longitudinally along the flute wall. The cutting edge structure has a first portion at the drill tip portion and a second portion disposed away from the drill tip portion. The flute wall extends further into the land structure at the second portion of the cutting edge structure than at the tip portion to provide a greater amount of drill material at the tip portion than at the second portion of the cutting edge structure.

Abstract: A drill bit capable of axial cutting as well as side cutting, having a generally cylindrical elongate body of a bit diameter, which comprises a frontmost drilling end for axial cutting, a cutting section extending from the drilling end for side cutting, and a shank behind the cutting section. The cutting section is helically cut at a helix angle of substantially 15°±2° to form one pair of diametrically opposite helical flutes whose outermost edges are sharpened to form respective cutting edges, around a solid central core whose diameter is substantially directly proportional to the bit diameter. The length of the cutting edges in the axial direction of the drill bit body is calculated according to the formula: Cutting Edge=Bit Diameter×&pgr;×CC/Tan(Helix Angle), CC being a constant of a value in the range substantially from 0.85 to 0.90.

Abstract: A cutting tool has a flute and land, which follow a helix angle, wherein the flute and land are connected to one another with a convex heel to provide a smooth contour to the tool surface and to provide improved performance. A grinding wheel for producing a cutting tool, along with a method for using such a grinding wheel, is also disclosed. Finally, a crush roll for dressing such a grinding wheel is also disclosed.

Abstract: A twist drill including a spiral-forming hollow shaft (3) having a spiral-shaped inner surface, and drilling head(5) and shank (6) connected with the shaft (3) at its opposite ends, respectively; and a method for forming such a twist drill.

Abstract: A drill bit for the working of metal has a center pilot tip that transforms into straight cutting edges extending towards the outer periphery of the bit. Each cutting edge forms a cutting angle of 1-20° with a reference plane oriented perpendicular to of the drill axis. Each a cutting edge is inclined in a radially inward and axially rearward direction toward the drill axis. The center tip forms a pilot point angle of 90±2° and a has base that takes up 23-45 percent of the total diameter of the cutting section of the drill bit. The tip has a tip angle of 90±10°.

Abstract: A corrosion-resisting, self-tapping screw (1), in particular a concrete screw, to be driven into a bore, which has a wall, comprises a substantially cylindrical core (2) of corrosion-resisting metal with a central longitudinal axis (8); a thread (5), which is integral with the core (2); and at least one cutting element (9), which has at least one cutting head (12) for cutting engagement with the wall of the bore; the at least one cutting element (9) being inserted in the core (2), tightly joined thereto and consisting of a hardened metal, and the at least one cutting head (12) being arranged in the thread (5).

Abstract: A drill comprising a shank part (11), which is adapted to be received in a drill holder of a drilling machine, and an opposite cutting end part (13). An intermediate fluted part (12) is provided, which defines at least one helical flute or channel (16) having a bottom surface (19) and a pair of opposite side surfaces (20) defined by the ribs or lands (17). The shape of a cross-section of said at least one flute or channel, taken at right angles to the course of the flute or channel, is such that the distance from a reference plane (24) to the bottom surface or the flute is decreasing from a central part (22) of the bottom surface towards the adjacent side surface (20) of the flute. Said reference plane is at right angles to a radial line (25) extending from the longitudinal axis of the drill and through the centre of the bottom surface width. A helically extending groove (21) is formed in the middle of the central part (22) of the bottom surface (19).

Abstract: The present invention relates to a drill having an aggressive drill point geometry. The point geometry allows greater stability and feed rates, while decreasing the heat generated at drill point. The present invention is provided by a drill comprising drill body having at least two helical flutes, a pair of cutting surfaces on an end of the drill body, a web formed between the two cutting edges, and a web thinning notch formed on either side of the web. Each notch forms a notch cutting edge having a positive rake angle.

Abstract: A drill having a cutting edge that is less prone to chipping or fracturing when used in drilling operations, and that can be sharpened or resharpened uniformly and consistently from drill to drill by machine grinding. The drill comprises a body and at least one flute formed in the body that terminates in a cutting edge at the cutting end of the drill. The flute has a cutting surface, the cutting surface having formed therein a dub face having a substantially planar surface over at least a portion thereof that is proximate to the cutting edge. The cutting edge has formed therein a cutting land having a substantially planar surface over at least a portion thereof connected at an edge to the planar surface portion of the dub face.

Abstract: A rock drill for rotary hammers is proposed in which a conveying helix (3) having main and secondary webs (6 to 9) is used. A one-piece carbide crown, with its wing-shaped main and secondary lips (24 to 27), is butt-welded to the conveying helix.

Abstract: A drill comprises a drill body and a removable tip. The drill body has a main body portion, a thread, and a reduced diameter portion between the main body portion and the thread. The removable tip has a main body portion and a thread that is adapted to engage the thread of the drill body. One of the threads is an internal thread within a connection bore. The other thread is an external thread extending from a shaft. The internal thread is defined by a front face, a rear face, and a radial surface extending between the front and rear faces. The external thread is also defined by a front face, a rear face, and a radial surface extending between the front and rear faces. The shaft is adapted to be inserted in the connection bore and rotated to engage the internal and external threads with one another.

Abstract: A rock drill (1) for cutting rock comprising an elongated, helical shaft (2), which has, at one end, an insertion part (3) and, at the end opposite, a tool head (4) with cutters (5) made of hard material, wherein the helical shaft (2) is at least partially coated with a colored layer (7a, 7b) and the layer forms a lengthwise running wear indicator marking (8) inside the helical groove (8).

Abstract: Coolant delivery channels are cut into the external cylindrical side walls of a cutting tool to direct coolant into the cutting flutes of the tool. Coolant delivered through the chuck of a rotary power tool will be conveyed by the channels into the flutes adjacent the cutting edges to provide optimum cooling of the cutting zone.

Abstract: The present invention provides a novel drill insert having chipbreakers, or chip splitting grooves formed through the cutting surfaces. The cutting tool insert has a specialized geometry including a chip splitting groove formed at a negative rake angle. The chip splitting grooves increase the cutting efficiency of the tool while allowing the edge strength to be increased while also allowing higher feed rates.

Abstract: Rotatable tool for chip removing machining includes a rotatable holder part and a cutting part that is detachably connected to a front end of the holder part. In the front end of the holder part, a forwardly open slot is formed, which separates two elastically flexible branches of the holder part. For clamping of the cutting part on the holder part, a male/female coupling is provided, which comprises a pin on either the holder part or the cutting part and a corresponding pin-receiving seat in the other part. If the pin is on the holder part, then a manually induced elastic deformation of the branches towards one another reduces the diameter of the pin to enable the pin to enter the female part. Subsequent return of the branches toward a rest state thereof causes the diameter of the pin to expand and tightly hold the cutting part.

Abstract: A rotatable tool for chip removing machining having a rotatable holder part and a cutting part that is detachably connected to a front end of the holder part. In a front end portion of the holder part, a forwardly open slot is formed, which separates two elastically flexible branches of the holder part. For clamping of the cutting part on the holder part, a male/female coupling is arranged, which comprises a centrical, male-like pin on one of the parts and a corresponding seat in the other part. Disposed on the holder part radially outside of the male/female coupling are thrust load carrying support surfaces, which surfaces are at least partially conical and are engaged by corresponding support surfaces of the cutting part. During a cutting operation, axial thrust loads transmitted to the axial thrust support surfaces cause the branches to be pressed in a direction intensifying the radial contact between the pin and the seat.

Abstract: A micro-drill has shank made of a stainless steel. A bit is integrated with the shank by welding and made of a tungsten carbide. A tapering portion is formed behind the bit. A welded segment is located between the shank and the bit. The micro-drill has a reinforced strength, and a minimum diameter of the bit can reach 0.1 mm.

Abstract: A method for reaming a hole in a metal substrate that minimizes the tendency of long and stringy metal chips to be formed that can surround the reamer with a “steel wool-like” mesh or mass of material, as well as an improved reamer for carrying out this method. The reaming method involves longitudinally advancing the chamfered end of the reamer into the hole at an increased rate of at least about 5 mils (0.13 mm) per cutting edge as the hole is reamed during rotation of the reamer. For holes or bores having a length (L) that is at least about 3 times the cutting diameter (D) of the reamer, a preferred subsequent step is to momentarily reduce the rate of advance of the chamfered end into the hole to about 1 mil (0.025 mm) or less per cutting edge for from about 1 to about 5 rotations of the reamer.

Abstract: The invention relates to a drilling tool for machine tools and to a method for the production thereof. The drilling tool has at least one chip conveyor groove (16) and at least one functional channel (20). In order to produce the body of the drill (10), the wall of a tubular metal blank is simultaneously impinged upon by substantially radially oscillating form-giving forces in several forming sections spread over the periphery, moving in an axial direction along the surface of the blank, whereby at least one chip conveyor groove (16) is shaped and at least one functional channel (20) is formed. When the chip conveyor grooves (16) are formed on at least two interspaced forming sections in a peripheral direction in the wall of the blank (50), the parts of the wall in the area of two opposite-lying chip conveyor grooves (16) come to rest against each other in a sealed manner, defining at least two functional channels (20, 24) on the inner surfaces thereof.

Abstract: A modified prior art twist drill embodies structural features that require less energy to drill a hole during a normal plunge operation and allow for lateral cutting movement during extraction of the twist drill from a drilled work piece.

Abstract: A cutting point for a drill including a body having a periphery. The cutting point includes a leading cutting lip and a trailing cutting lip and a central chisel edge extending between the leading and trailing cutting lips and defining two symmetrical drill point halves. Each drill point half includes a primary relief surface, a secondary relief surface and a third relief surface. The third relief surface is inclined at an angle greater than the secondary relief surface and the secondary relief surface is inclined at an angle greater than primary relief surface.

Abstract: A rotatable tool has a replaceable tip mounted thereon. The tool includes a tool body having a cutting seat in which the tip is received. The tip has edges for chip removing machining. The cutting seat and the replaceable tip have mutually cooperating support surfaces extending transverse to the longitudinal center axis of the tool. The cutting seat and the replaceable tip have mutually cooperating guide surfaces which are symmetrical about the longitudinal center axis as well as clamp portions for clamping the replaceable tip in the axis direction of the tool. A locking screw is received in the tool body to bring the replaceable tip into cooperation with the clamping portions.

Abstract: The present invention provides a drill comprising: a drill main body rotatable about an axis of rotation, and having a tip end with a tip flank and a shank; a chip discharge flute formed on a periphery of the drill main body, and extending from the tip end toward the shank of the drill main body; and a cutting edge formed along an intersecting ridge where a wall surface of the chip discharge flute facing in the direction of drill rotation intersects the tip flank of the drill main body, wherein the cutting edge comprises a convex cutting edge toward the periphery and a concave cutting edge smoothly extending from the convex cutting edge.

Abstract: A method for influencing the swarf flow behaviour of tool surfaces in the region of cutting edges with swarf producing tools with a geometrically defined cutter, by laser irradiation of the tool surface, wherein with the help of the laser irradiation at least the faces at a slight distance to the cutting surface are provided with a geometric pattern changing the surface structure.

Abstract: A tool tip and tool body assembly includes a tool tip having a first end for contacting a workpiece and a second end, the second end having a patterned surface of recesses and protrusions, and at least one through hole extending through the tool tip from the second end. A tool body has a first end having a patterned surface corresponding to the patterned surface of the tool tip for mating with the patterned surface of the tool tip, and at least one threaded hole adapted to align with the at least one through hole in the tool tip. At least one fastener having a threaded end and a securing end is provided, the fastener extending through the at least one through hole such that the securing end abuts against a surface in the at least one through hole, the threaded end mating with threads in the threaded hole. Torque is transmitted between the tool tip and the tool body solely by the at least one fastener and the patterned surface of the tool tip and the patterned surface of the tool body.

Abstract: A boring bit includes a body having a spirally formed flute in an outer periphery thereof and a tool engaging end is connected to a first end of the body. A recess is axially defined in a second end of the body and a radial threaded hole is defined radially in the body and communicates with the recess. A lead portion has an engaging portion on a first end thereof and a threaded lead screw on a second end of the lead portion. The engaging portion is received in the recess and a bolt is engaged with the threaded hole and contacts the engaging portion. The threaded lead screw is easily replaced by removing the bolt.

Abstract: Rotary cutting tool, in particular for high speed machining with nano-lubrication.

Abstract: A cutting tool is provided with a margin that includes a modified margin portion adjacent the terminal end of a circumferential face of the cutting tool that is smaller in width than the width of the base portion of the margin. The cutting tool is manufactured from a blank by removing portions of the blank to create flutes and interposed circumferential faces. A recessed portion on the circumferential faces is created to provide the margins, a point is provided at the cutting end, and a portion of the margin is removed on at least one of the circumferential faces between the terminal end of the circumferential face and a distance L from the terminal end. A cutting tool may be provided with a modified margin during reconditioning of the cutting tool. The modification may be done before or after the removal of worn or damaged sections of the cutting tool.

Abstract: A throw-away tip for use in drilling work that has a convexly curved cutting edge portion at one end side of a cutting edge is provided. Chips are prevented from being sheared and packed, and cutting edge strength is secured to extend the service life of the tip. The tip is used with a drilling tool having a tool body rotatable about an axis and has a convexly curved surface formed on a rake face thereof on the one end side of the cutting edge, which forms a curve toward a seat face thereof as it proceeds toward the one end side of the cutting edge.

Abstract: A separable rotary cutting tool is disclosed. The tool comprises a shank and a head. The shank has a receiver comprised of a shank guide at a trailing end of the receiver, opposing shank drive keys at a leading end of the receiver, and a shank locator located axially between the shank guide and the shank drive keys. The shank drive keys each comprises an axially extending shank drive key radial stop surface that is disposed at an angle relative to a plane extending through a central axis of the receiver. The head has a connector comprised of a head guide at a trailing end of the connector, opposing head drive keys at a leading end of the connector, and a head locator located axially between the head guide and the head drive keys. The head drive keys each comprises an axially extending head drive key radial stop surface that is disposed at an angle relative to a plane extending through a central axis of the connector.

Abstract: A rotatable tool includes a shaft and a cutting head mounted thereto. The shaft defines a longitudinal axis of rotation and has a seat formed at a front end thereof which includes a first engagement surface. The cutting head is attached on the seat and includes a second engagement surface engaging the first engagement surface for longitudinally locking the cutting head to the shaft. The first and second engagement surfaces include respective first and second support surfaces which together form a planar interface, the interface defining a contact line when viewed longitudinally toward a front end of the tool. The contact line intersects an outer periphery of the cutting head at a point. The contact line extends from the point in a direction forming an acute angle with a radius that intersects the point. The contact line is disposed rotationally ahead of the radius with reference to rotation of the tool.

Abstract: The invention relates to a drill bit (2), having main cutting edges (4a, 4b) which are connected together by a transversal cutting edge (6). An open surface (7) which extends into a flute (8) lies adjacent to each main cutting edge. The drill bit (2) is ground, in particular, during a continuous three-dimensional grinding process in such a way that the open surface (7) forms a continuous curved surface which follows a radius of curvature (R) running from the main cutting edge (4a) in the direction of the flute (8). The continuous grinding process, in comparison to a conventional two-stage process, produces an improved drill bit geometry which is devoid of ridges (16). The ridge-free configuration reduces the mechanical stress during drilling to a minimum.

Abstract: The present invention provides a new cutting tool assembly comprising a replaceable cutting head and a tool body having a common longitudinal axis and mating peripheral surfaces. The cutting head has a cutting portion forming a leading end, a pilot portion forming a trailing end, and a cutting head mounting portion adjacent the trailing end of the cutting head. The tool body has a cutting head receiving portion formed at a leading end of the tool body and a pilot recess disposed in the leading end of the tool body to matingly receive the pilot portion of the cutting head. The cutting head mounting portion and the cutting head receiving portion of the tool body each have at least two coupling portions. The cutting head coupling portions and the tool body coupling portions are bound by their peripheral surfaces and generally mate in shape and dimensions. Each coupling portion has a pair of base surfaces, including upper and lower surfaces.

Abstract: A drilling tool includes a shaft having a front end to which a cutting body provided with cutting edges is detachably connected. In the front end of the shaft, a seat is formed which is delimited by spaced-apart protrusions between which there is a bottom surface. In the protrusion, there is a threaded hole for a screw, which when tightened applies pre-stressing forces to the cutting body. On the inside of the opposite protrusion, there is a supporting shoulder against which the cutting body is pressed when the screw is tightened and applies a lateral pre-stressing force to the cutting body. The protrusions are laterally displaced in relation to each other in order to freely expose the screw beside one of the protrusions.

Abstract: The present invention provides a new cutting tool assembly comprising a replaceable cutting head and a tool body having a common longitudinal axis and mating peripheral surfaces. The cutting head has a cutting portion forming a leading end, a pilot portion forming a trailing end, and a cutting head mounting portion adjacent the trailing end of the cutting head. The tool body has a cutting head receiving portion formed at a leading end of the tool body and a pilot recess disposed in the leading end of the tool body to matingly receive the pilot portion of the cutting head. The cutting head mounting portion and the cutting head receiving portion of the tool body each have at least two coupling portions. The cutting head coupling portions and the tool body coupling portions are bound by their peripheral surfaces and generally mate in shape and dimensions. Each coupling portion has a pair of base surfaces, including upper and lower surfaces.

Abstract: A boring tool is proposed which has a cutting portion at one end thereof, a driver engaging portion at the other end thereof, a shank arranged between the cutting portion and the driver engaging portion. The shank is formed with a helical groove for discharging cuttings. The driver engaging portion has a hexagonal outer shape and is formed with a hexagonal hole and a recess at bottom of the hexagonal hole for receiving the tip of a driver. The cutting portion has a pointed tip and a substantially conical shape, a first recess formed by cutting off substantially a 180° section of the cutting portion as seen axially from the pointed tip with an edge in the rotational direction forming a cutting edge, and a second recess formed by cutting off substantially a 90° section of the remaining 180° section. The second recess is separated from the first recess by a thin-walled partitioning wall.

Abstract: A twist drill, having a replaceable drill tip, comprising a drill bit shaft (1), a cutting insert (2) which is detachably fixed thereto and which forms the tip area of the twist drill, and comprises a flute (3) that continues into the cutting insert (2). The cutting insert rests, with a bearing surface (6) extending orthogonal to the center longitudinal axis (8) of the drill bit, on the face (7) of the drill bit shaft (1) and extends with a fixing stud (9), which centrally protrudes from the bearing surface (6), into a receiving recess (10) which is configured complementary thereto and which is provided in the face (7) of the drill bit shaft (1).