Abstract: In a drill in which a chip discharge groove twisted in the shape of a spiral relative to an axis is formed in the outer periphery of the tip section of a roughly cylindrical drill body that rotates around the axis, and a cutting edge is formed on the intersecting ridgeline between a wall surface facing in the direction of drill rotation of this chip discharge groove and a tip flank of the drill body, together with the section on the tip side of the chip discharge groove continuous with the cutting edge being a narrowed width section in which the helix angle relative to the axis and groove width are constant, a wide width section is formed in the chip discharge groove farther towards the rear end than this narrow width section, in which the helix angle is equal to the narrow width section and in which the groove width is widened relative to the narrow width section in the direction of drill rotation and towards the rear in the direction of drill rotation and has a constant width.

Abstract: A drill for hard materials, comprising webs that are subdivided by means of cutting grooves, and at least one principal cutting edge, each of which is provided with a cutting corner and a transition to a chisel edge. At least some sections of the principal cutting edge are continuously convex in an axial direction starting from the cutting edge.

Abstract: A preferably rotationally driven tool is specified for the deburring of openings, such as for example bores that open laterally into an essentially cylindrical recess. The tool has a cutting head that is seated on a shaft and that has at least one cutting edge that extends, at least in segments, in the axial direction. So that the deburring can be carried out reliably and with the lowest possible expense, a radial force-producing device is integrated into the tool, for example in the form of at least one internally situated flow medium channel, from which at least one branch channel goes out that opens in the area of the cutting head or in the vicinity thereof, preferably at a peripheral distance to the at least one cutting edge, in the external peripheral surface thereof.

Abstract: An elongate drill bit (20) with a longitudinal axis (X-X) has a shank (28), a working end (24), and a fluted section (26) between the shank and the working end. The shank, the working end and the fluted section are all formed integrally in the drill bit. The working end has an outer cutting portion (34) and a central pilot tip (36) which extends axially ahead of the outer cutting portion. The pilot tip is formed with at least one pair of minor cutting edges (40, 42; 44, 46) arranged on opposite sides of the axis. The outer cutting portion is formed with a pair of major cutting edges (70, 72) arranged on opposite sides of the axis. The outer cutting portion has a major diameter (D) defined by the pair of major cutting edges. The pilot tip has a minor diameter (d) defined by the at least one pair of minor cutting edges.

Abstract: A drill for chip removing machining, including a front tip including at least one cutting edge and a chip flute. The chip flute is countersunk in an envelope surface of a body of the drill and extends rearwardly from the cutting edge. The chip flute is generally defined by a cross-section-wise concavely vaulted surface located between first and second longitudinal borders, the first longitudinal border extending from an area of a peripheral end of the cutting edge. The chip flute is deeper in an area of the first longitudinal border than in an area of the second longitudinal border such that a curve defining the cross-sectional shape of the flute surface has a radius of curvature that is smallest in the vicinity of the first longitudinal border and that increases towards the second longitudinal border. The flute surface transforms into a planar chip surface, which in turn transforms into the cutting edge.

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: A metal cutting drill bit has a shank portion, a flute portion defining a helix angle and a tip. The tip has a primary cutting edge extending to an outer periphery of the drill bit. The primary cutting edge has a rake face defining a rake angle. The rake angle is different from the helix angle at the tip of the drill bit.

Abstract: The present invention discloses a reamer (20) and a method for reaming, for enlarging a pre-existing hole in a workpiece by rotational and axial cutting. The reamer (20) includes a body (24) extending from a shank (22). The body (24) has a first flute (30) providing a first flute cutting edge (32) at a distal end (34) of the body (24) for imparting a first cutting operation to the workpiece. The body (24) has a helical flute (42) providing a helical flute cutting edge (46) in the body distal end (34), radially spaced apart from the first flute cutting edge (32) for imparting a helical cutting operation to the workpiece. The first flute and helical flute cutting edges (32, 46) concurrently and collectively perform the first and helical cutting operations to a sculpture surface of the workpiece, thereby improving tolerances of the cutting operations, varying loads imparted to the workpiece and the reamer (20), and reducing heat generated therebetween.

Abstract: A twist drill and method for producing is provided. 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. 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 flute volume per length at the second portion of the cutting edge structure than at the drill tip portion.

Abstract: A drill for producing a deep hole that does not produce a bend of the hole during cutting. A drill body is spirally provided with a pair of cutting edges. The cutting edges are spaced at about 180 degrees apart around a core of the drill and the edge line of a tip section of the cutting edges is depressed toward the core of the drill. When the outside dimension of the drill is 7.4 mm, an angle between the edge line and a line perpendicular to the core is 5 degrees and the core thickness (t) is 2.96 mm. Further, the drill is provided with a guide section for preventing bending during a cutting operation. The guide section is provided on a heel side on the same circumference as that on which the outer end section of the cutting edges passes.

Abstract: A method of forming deep holes and a gundrill therefore is disclosed. The gundrill has an elongate tubular shank and a cutting tip, each provided with a tubular central region supplying pressurized drilling fluid and a non-circular fluid cross-section defining a drilling fluid return path in conjunction with the hole being formed. The cutting tip flute defines a primary rake surface terminating in an offset point, and a secondary flank surface for forming an outlet with the hole being drilled, sized to maintain fluid pressure in the bottom end space to cool the cutting surfaces and to effectively remove chips as they are formed. A localized relief passage, sized relative to the outlet passage to cause a significant amount of drilling fluid to flow therethrough, is formed behind a peripheral rake edge of the primary rake surface for drilling fluid to exit the end space and cool the tip.

Abstract: The invention concerns a drill including a generally cylindrical body, tipped with a head and provided, over at least part of its length, generally spiral evaporating grooves. The groove(s) are delimited, over at least part of their length, by a succession of facets, attached to one another, and linked to one another by sharp edges or by radius blends.

Abstract: The present invention is directed to a helical drill configuration that allows substantially flat bottomed holes to be machined. At the cutting end of the body member, there are at least two cutting edges that are symmetrically oriented on apposing sides of the rotational axis of the drill. In an embodiment of the invention, first and second cutting edge portions form a continuous surface which provides strength and tool stability. The height of the second portions of each of the cutting edges remains relatively consistent along the horizontal for formation of a generally flat bottom hole. In the embodiment, a center point is defined by two sloped peak surfaces. A central straight chisel edge is formed by the intersection of the two sloped peak surfaces. The first cutting edge section extends from the chisel edge to the second cutting edge section. The first cutting edge section for both cutting edges is formed by symmetrically thinning the two peak surface.

Abstract: A cutting tool for rotary cutting includes a rotatable basic body and a replaceable cutting part or loose top, which is connectable to the basic body via a male/female coupling, which includes a groove and a male part. The groove is formed in a front end of the basic body and is delimited by a bottom surface and two side surfaces. The male part is insertable into the groove along the axis of rotation and protrudes rearwardly from the loose top. The male part has an end surface and two flank surfaces. In the front part of the basic body a forwardly open slot is formed, which separates two elastically deflectable legs wich clamp the male part in the groove. In either the end surface or the bottom surface a recess is formed for receiving a projection on the other surface. The recess is larger than the projection in order to enable the male part to reciprocate a short distance in the groove, whereby the loose top is self-centering with respect to the axis of rotation.

Abstract: A cutting tool insert and holder therefore, the drill insert having a helical geometry corresponding to helical flutes in a drill body holder which enable the drill tool assembly to more efficiently remove chips from a hole during operation, the drill insert comprising a drill insert body having a first end opposite a second end, a plurality of helical flutes formed in the drill insert body, a plurality of cutting edges formed at the interfaces of the plurality of helical flutes and the first end of the drill insert body, and an aperture formed in each helical flute.

Abstract: The invention concerns a drilling instrument (10), in particular for drilling dental root canals comprising a base (11) and a guide section (13) as well as a polygonal cutting section (12). Said cutting section includes several helical cutting edges (17) defining an envelope (15). The flutes (14), which are the surfaces linking in the cutting edges, are cut out such that part of them define clearance zones (16a) alternately arranged between the drilling zones (16b). In the central part of a clearance zone (16a), the cutting edges (17) are all arranged recessed inside the envelope (15), in the central part of the drilling zone (16b), said cutting edges are all arranged on the envelope, and in a zone intermediate between a clearance zone (16a) and an adjacent drilling zone (16b), at least one cutting edge is on the envelope and at least one cutting edge is recesses inside the envelope.

Abstract: A rotatable tool for chip removing machining includes a drill shank, and an exchangeable loose top mounted at an axially front end of the shank. Between these there is a coupling, which includes a male part on the loose top, and a groove in the basic body. By means of a slot, two deflectable legs are defined by the shank, which legs form a jaw for receiving and clamping the male part. The maximal width of the jaw upon deflection of the legs away from one another is larger than the maximal breadth of a wedge portion included in the male part. Furthermore, the angles of inclination of flank surfaces on the male part and side surfaces in the groove, are equally large in order to guarantee surface contact between said surfaces, when the legs are resiliently tightened against the male part. The wedge portion is of dovetail shape, wherein the loose top is drawn axially against the shank as it is being radially clamped by the legs.

Abstract: A twist drill including a cutting tip having a front flank face, a substantially cylindrical tool body extending rearwardly from the cutting tip, and a shank. The tool body includes a rotational axis therethrough and at least one flute formed on an outer peripheral surface thereof and extending to the front flank face. The at least one flute includes a first helical portion opening to the front flank face and a second helical portion extending from the rear end of the first helical portion toward the rear portion of the tool body. The second helical portion twists in a direction opposite of the first helical portion.

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).

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: The drill of the present invention has only one cutting discharge groove (11) formed in the outer periphery of a bit (10). A leading edge protruding farthest towards the tip in the axial direction in a tip flank (12) is composed at a single point and located on an axis (O). When bit is viewed from the tip side in the direction of axis, tip flank is in the form of a multilevel surface composed of second through fourth flanks (14B, 14C and 14D) arranged along the peripheral direction, and a reverse side first flank (14E) surrounded by second through fourth flanks and intersecting with axis.

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: On a drill with a base body and a replaceable cutting insert, the cutting insert lies in a receptacle that runs through the base body at a right angle to the latter's longitudinal axis and is open toward the drill tip, whereby the cutting insert is in contact by means of two diametrically opposite contact surfaces against the side walls of the receptacle. Between each contact surface of the cutting insert and a side wall of the receptacle, there is a groove that extends in the direction of the longitudinal axis, in which groove a clamping wedge sits with a form-fit and a friction-fit, and interacts with the base body and the cutting insert in the manner of a self-locking device that acts toward the drill tip.

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: A small drill includes one chip-discharging flute which is helically formed in the exterior surface of a cutting portion of the small drill. The small drill also includes a flute-shaped portion which is formed in the front region of the chip-discharging flute in the rotating direction, which is connected to the chip-discharging flute, and which is open at the exterior surface of the cutting portion. The core diameter ratio d/D, in percent, of the small drill is set to 60% or more, and a margin angle ? thereof is set to 120° or more.

Abstract: A drilling tool set includes a plurality of drilling tools having different operative drill diameters to blast drill holes of different respective diameters. Each drilling tool of the set has a basic body defining a central axis of rotation, and two replaceable indexable bits including a center bit and a periphery bit which are mountable in respective center and periphery pockets formed in a front end of the basic body. The periphery bits of the respective drill tools of the set are identical, and the center bits of the respective drill tools of the set are identical. Each of the center and periphery pockets of each drill tool defines a radial center point. A first of the drill tools has a smaller operative drill diameter than a second of the drill tools. The first tool includes a first periphery pocket and a center pocket. The center point of the first periphery pocket is disposed closer to the axis than is the center point of the second periphery pocket.

Abstract: There is now provided a rotary cutting tool, particularly a drill, that has at least two cutting edges that respectively comprise a main cutting edge and that respectively are disposed, particularly symmetrically, with respect to the central axis of a cutter portion, whereby the radius of the main cutting edges is less than the maximal cutting edge radius of the cutter portion. A secondary cutting edge is associated with a main cutting edge, this secondary cutting edge is curvilinear in at least a portion and is configured as smooth finishing cutting edge, this secondary cutting edge comprises a plurality of curve-forming radii, whereby in an outer smooth finishing region within the region of the maximal cutting edge radius, the curve-forming radius of the smooth finishing cutting edge is greater than the maximal cutting edge radius. The cutter portion that is adjacent to the outer smooth finishing region is tapered by a taper that diminishes the size in the direction away from the main cutting edges.

Abstract: A drilling tool includes a basic body defining a center axis of rotation and having two chip channels and two replaceable indexable cutting bits in the form of a center bit and a periphery bit mounted in respective center and periphery pockets formed in an axially front end of the basic body. The center bit and the center pocket are spaced radially from the periphery bit and the periphery pocket along a first diametrical plane of the basic body. At least the center bit includes four identically-shaped cutting edges, one of which constituting an operative cutting edge intersected by a second diametrical plane oriented perpendicularly to the first diametrical plane. Each cutting edge of the center bit comprises first and second part edges joined by a transition edge portion.

Abstract: A drill including a shank portion and a cylindrical body portion contiguous to each other. The cylindrical body portion includes (a) primary cutting edges and secondary cutting edges formed in its axially distal end portion such that each of the secondary cutting edges is located on a radially inner side of the corresponding primary cutting edge; (b) primary rake surfaces of the primary cutting edges and secondary rake surfaces of the secondary cutting edges; and (c) inclined surfaces each of which extends from the corresponding secondary rake surface to a periphery of the cylindrical body portion, and is inclined such that an axial distance between each of the inclined surfaces and the shank portion is reduced as viewed in a direction substantially perpendicular to the corresponding secondary cutting edge, from the corresponding secondary rake surface toward the periphery of the cylindrical body portion.

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 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 rotatable tool for chip removing machining includes two parts, viz. a holder part, rotatable around a geometrical center axis, and a replaceable cutting part, which is rigidly connectable to a front end of the holder part via a male/female coupling. The coupling includes a tapering seat in the holder part and a tapering male member, protruding rearwardly from the cutting part. In the seat, there is a slot, which separates two elastically deflectable projections, that may be inwardly deflected towards each other during clamping of the male member in the seat. The male member is elongated in a radial direction, and the seat is in the form of a radial groove into and out of which the sheath body is transversely movable. The male member includes a dove-tail shaped portion received in a dove-tail shaper portion of the groove. A centering button on the male member enters a depression in the holder part to axially center the cutting part.

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 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 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: A drill for chip forming metalworking includes three cutting edge structures spaced circumferentially apart. Each cutting edge structure includes a radially outer cutting edge and a radially inner cutting edge. Each radially inner cutting edge is inclined in a radially inner and axially rearward direction from a radially inner end of its associated radially outer cutting edge. That radially inner end constitutes a breakpoint between each radially outer cutting edge and its respective radially inner cutting edge. The breakpoints lie in a common circle whose center coincides with the center axis of the drill.

Abstract: In a throw-away tipped drill, a slit is formed at the bottom surface of a tip attachment seat which faces towards the end of its axial line direction, with this slit extending towards the rear of the axial line direction. Furthermore, when seen from the end of the axial line direction, this slit is arranged as being displaced so as to be closer to a second end portion into which a shaft portion of a clamp bolt is threaded than to a first end portion which is pressed by a head portion of that clamp bolt. As a result, when, using the clamp bolt, the pair of outer side surfaces of the tip are pressed by the pair of internal side surfaces of the tip attachment seat, the pressing forces are mutually equal to one another.

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: The present invention is directed to a helical drill configuration that allows substantially flat bottomed holes to be machined. At the cutting end of the body member, there are at least two cutting edges that are symmetrically oriented on apposing sides of the rotational axis of the drill. In an embodiment of the invention, first and second cutting edge portions form a continuous surface which provides strength and tool stability. The height of the second portions of each of the cutting edges remains relatively consistent along the horizontal for formation of a generally flat bottom hole. In the embodiment, a center point is defined by two sloped peak surfaces. A central straight chisel edge is formed by the intersection of the two sloped peak surfaces. The first cutting edge section extends from the chisel edge to the second cutting edge section. The first cutting edge section for both cutting edges is formed by symmetrically thinning the two peak surface.

Abstract: The drill of the present invention has only one cutting discharge groove (11) formed in the outer periphery of a bit (10). A leading edge protruding farthest towards the tip in the axial direction in a tip flank (12) is composed at a single point and located on an axis (O). When bit is viewed from the tip side in the direction of axis, tip flank is in the form of a multilevel surface composed of second through fourth flanks (14B, 14C and 14D) arranged along the peripheral direction, and a reverse side first flank (14E) surrounded by second through fourth flanks and intersecting with axis.

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: In a drill in which a chip discharge groove twisted in the shape of a spiral relative to an axis is formed in the outer periphery of the tip section of a roughly cylindrical drill body that rotates around the axis, and a cutting edge is formed on the intersecting ridgeline between a wall surface facing in the direction of drill rotation of this chip discharge groove and a tip flank of the drill body, together with the section on the tip side of the chip discharge groove continuous with the cutting edge being a narrowed width section in which the helix angle relative to the axis and groove width are constant, a wide width section is formed in the chip discharge groove farther towards the rear end than this narrow width section, in which the helix angle is equal to the narrow width section and in which the groove width is widened relative to the narrow width section in the direction of drill rotation and towards the rear in the direction of drill rotation and has a constant width.

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 drill including a cylindrical main body and a shank. The cylindrical main body has: (a) flutes providing cutting edges at an axially distal end of the cylindrical main body; (b) lands each provided by a peripheral portion of the cylindrical main body and located between the flutes; and (c) a web provided by a central portion of the cylindrical main body which joins the lands and extends in an axial direction of the cylindrical main body. The web includes a back-tapered portion which is provided by at least an axially distal end portion of the web, such that a thickness of the web in the back-tapered portion is gradually or continuously reduced as viewed in a direction away from the axially distal end of the cylindrical main body toward the shank.

Abstract: The invention concerns a drill comprising a generally cylindrical body (2), tipped with a head (3) and provided, over at least part of its length, generally spiral evaporating grooves (5). The groove(s) (5) is/are delimited, over at least part of its/their length, by a succession of facets (7), attached to one another, and linked to one another by sharp edges or by radius blends (8).

Abstract: A drill comprising a tip-forming end including at least two cutting edges (8, 8′) and at least two chip flutes (7, 7′) extending from the tip end (2) towards the second end (3), having the purpose of forming and removing chips from the corresponding cutting edge. In accordance with the invention the drill tip is composed of cutting edges on mutual sides of the axial centre line having a straight unbroken contour, the central portions of which extend axially beyond the peripheral portions whilst the nose radiused surface on each cutting edge at the periphery is provided with a smoothly curved radius comprising one or several circular segments with mutually different radii (R1, R2, R3) where adjacent radii always appear with different size.

Abstract: A small drill includes one chip-discharging flute which is helically formed in the exterior surface of a cutting portion of the small drill. The small drill also includes a flute-shaped portion which is formed in the front region of the chip-discharging flute in the rotating direction, which is connected to the chip-discharging flute, and which is open at the exterior surface of the cutting portion. The core diameter ratio d/D, in percent, of the small drill is set to 60% or more, and a margin angle &thgr; thereof is set to 120° or more.

Abstract: A rotatable cutting tool includes a rotatable tool body and a replaceable cutting tip for chip removing machining. The tool body includes a forward free end having a first dovetail coupling part formed thereon. The cutting tip includes a front cutting end and a rear mounting end. The mounting end includes a second dovetail coupling part joined to the first dovetail coupling part. An actuator, such as a screw, is provided which is arranged for elastically deforming one of the dovetail coupling parts to create a tightly clamped relationship between the first and second dovetail coupling parts. Insertion of a replacement cutting tip is performed by laterally mating the dovetail coupling parts until one of the coupling parts abuts a laterally facing stop surface of the other coupling part.

Abstract: A method of making a drill comprising a tip (16), a shank (10) and a flute area having chip spaces (12, 14) formed therein, the drill being substantially completely coated with a hard material, and is characterized by applying an abrasive material to merely the tip (16) before coating the drill with the hard material. The drill may more particularly be a solid carbide drill.