Abstract: A drilling tool includes a step drill bit and an arbor assembly. The arbor assembly includes a shank having a first end, a second end opposite the first end, and a longitudinal axis extending through the first and second ends. The first end of the shank is removably coupled to the step drill bit, and the second end of the shank is configured to be coupled to a power tool. The arbor assembly includes a sleeve moveable along the shank parallel to the longitudinal axis, and a ball bearing disposed on the sleeve and moveable with the sleeve. The ball bearing engages the step drill bit to releasably secure the step drill bit to the shank. When the sleeve moves toward the second end of the shank, the ball bearing moves radially inward and disengages the step drill bit, allowing removal of the step drill bit from the shank.

Abstract: A partial hip prosthesis for reducing friction and wear in partial hip prosthesis by combining optimized geometry of the articulation and surface treatment of the prosthetic component. In the prosthesis, one of the articulating surfaces—either that of the reamed acetabulum, or that of the femoral head prosthesis is a-spherical so that a fluid-filled gap is formed at the area of major load transfer. The fluid-filled gap is sealed by an annular area of contact, over which the concave and the convex components are congruent. A prosthetic head is fixed to the femur by either a conventional stem, a perforated shell, or a femoral neck prosthesis screwed onto the femur so that it is partially covered by bone and partially exposed on the medial-inferior aspect, where it abuts the reamed cortex of the calcar region.

Abstract: 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=0.95×D/4 to L1=1.2×D/4. Each of the first and second lateral sides has a length LS1, LS2 within a range of D/4 to 1.3×D/4. The first and second lateral sides diverge from each other in a direction radially outwards from the radially inner side.

Abstract: Methods of implanting a prosthesis to repair a joint include displacing a first bone from the joint formed by an intersection between the first bone and a second bone. An end portion of the first bone is resected to define a resected end. A concavity is formed into the resected end using a shaping tool. The bone is compacted to form a support layer lining the concavity. The prosthesis is implanted in the concavity against the support layer without attaching the prosthesis to the support layer. The joint is reformed with the prosthesis such that the prosthesis remains unattached to the support layer and the first and second bones articulate about the prosthesis.

Abstract: A milling cutter having a shank and a cutting head attached to the shank. The cutting head has a plurality of helical teeth, each tooth including a cutting tip, a leading face and a rear face. A flute is defined between the leading face of a trailing tooth, and a rear face of an immediately preceding tooth. A gully of the flute is generally W-shaped in cross section to provide effective chip evacuation. A method for manufacturing the milling cutter with the W-shaped gully of the flute using a split path grinding process is also disclosed.

Abstract: The present invention is concerned with twist drills for drilling of composite materials such as carbon fibre reinforced plastic (CFRP) and glass fibre reinforced plastic (GFRP). The present invention proposes that a twist drill (2) is provided with a variable helix having a defined start and finish helix angle, in combination with primary and secondary relief angles such that the drill (2) is adapted to minimise thrust force, particularly when used for drilling fibre-containing composite materials and especially for hand drilling. Start and finish helix angles of 50° and 10°; 50° and 30°; and 30° and 10° have been shown to provide excellent cutting performance and exit hole quality. A large secondary chisel edge angle (24) has also been found to contribute to excellent performance with composite materials, including stack machining.

Abstract: A system and method for a composite finishing system. The composite finishing system comprises an abrasive bit with an abrasive material on a removal surface of the abrasive bit, where in the abrasive bit has a pilot structure that positions an abrasive surface relative to an edge break intersection of a hole in a composite structure when a pilot structure is placed into the hole.

Abstract: Provided is a drill having a flat-shaped drill tip and excellent in cutting edge strength and chip removability. The drill includes: a cutting edge extending in a direction at an angle ? of not less than 85° and not more than 90° with respect to a drill axis (line O-O); a flank face contiguous to the cutting edge and having a clearance angle ? of not less than 5° and not more than 10° with respect to the drill axis (line O-O); and a rake face located opposite to the flank face across the cutting edge, the cutting edge includes a recess receding in a direction parallel to the drill axis (line O-O), and the rake face includes a front clearance formed at a side of an outer periphery of the drill.

Abstract: A cutting tool is configured to cut and countersink a hole in a workpiece. The cutting tool includes a shank and a fluted body extending along an axis. The body includes a tip, a chamfer in an axially spaced relationship with the tip and a cross hole with a proximal end opening to the chamfer. The body has a cutting section extending between the tip and the chamfer, and a countersinking section extending along the chamfer. At the cutting section, the body includes at least one hole-cutting edge. At the countersinking section, the body includes a scalloped countersink-cutting edge along a junction of the chamfer and the proximal end of the cross hole.

Abstract: A cutter for electrode graphite which has a shank at one end and a tool tip at the other end, and flutes extending from the shank to the tool tip, which space machining lands apart from each other in the circumferential direction. The tool tip is formed as a ball head section, in which the machining lands have a rounded contour, extending along a ball head radius. At least one of the machining lands is a rough-machining land and at least one other of the machining lands is a fine-machining land. Each machining land has a circumferential working area with a cylindrical surface-segment-shaped shell surface, the working area of each rough-machining land is a circumferential file with teeth which are worked into the shell surface of the working area, and the working area of each fine-machining land exterior grooves extends with a twist about the tool axis.

Abstract: A device for opening a connection to a lined pipe is disclosed. The device has a body that includes a front end and a rear end and being rotatable about a rotation axis. The device also has a drill head that has multiple cutters for puncturing and enlarging a hole in a liner, and multiple side cutters have at least one cutting edge parallel to the rotation axis. A safety ring is disposed on the body between the drill head and the side cutters. The safety ring has a circular periphery extending beyond the drill head and the side cutters in a direction perpendicular to the rotation axis.

Abstract: A drill bit for drilling laminates includes at least two main chip flutes separated by corresponding webs. The free end faces of the webs form relief surfaces. At least one secondary flute, which is formed in the periphery of each of the webs divides the web into a main and a secondary web. A main cutting edge is formed by the intersection of a main chip flute and a relief surface on the main web. A secondary cutting edge is formed by the intersection of the secondary flute with a relief surface on the secondary web following the main cutting edge in the direction of operation, the main cutting edges extending to the nominal radius of the drill. The secondary cutting edges terminate at a distance before the nominal radius and axially project from the main cutting edge by an axial overhang at least along their radially outer section.

Abstract: A method for manufacturing a roof-bolt drill bit includes providing a bit body rotatable about a rotational axis, the bit body having at least two cutting element support structures, each of the at least two cutting element support structures including a mounting surface for mounting a cutting element to the bit body and a trailing support surface. The method includes forming an internal passage within the bit body, the internal passage extending from a rearward opening defined in the rearward end of the bit body through at least a portion of the bit body, and forming a fluid port within each of the at least two cutting element support structures, each fluid port extending from the internal passage to a port opening defined in the corresponding cutting element support structure, each port opening being positioned adjacent to the mounting surface of the corresponding cutting element support structure.

Abstract: A drill bit for a drill includes at least one flute having a rake face including a flute edge and at least one cutting edge having a profile that extends along at least a portion of a length of the cutting edge, the rake face extending from the cutting edge. A chip breaker formed in the rake face, the chip breaker being a continuous groove located adjacent the cutting edge, the groove having a starting end and an exit end opening into the flute edge, the starting end having a depth that is less than a depth of the exit end of the groove, wherein a shape of the groove at the starting end is different from a shape of the groove at the exit end.

Abstract: A deburring tool has a hollow top portion having an interior conical surface and an exterior surface. The exterior surface of the deburring tool is preferably conical. The top portion has a plurality of flutes formed therein and extending between the interior and exterior surfaces. Each of the flutes has a cutting edge formed at the interior conical surface. In operation, rotation of the deburring tool about a longitudinal axis removes burrs projecting from bar stock contacting the interior conical surface. A method of deburring bar stock comprises: (a) rotating the deburring tool about a longitudinal axis, and (b) contacting the bar stock to the deburring tool interior conical surface.

Abstract: The present disclosure relates to cutting tools and cutting inserts in general, and more particularly to the specific shapes of cutting edges on cutting tools and cutting inserts. In an embodiment, a cutting tool with a cutting edge formed as a sinusoidal curve is provided. In an embodiment, a rotary drill bit including a cutting insert comprising a sinusoidal curve is provided.

Abstract: According to one implementation, a drill has at least one cutting edge. A projected shape of a passing area of a ridgeline of the at least one cutting edge when the at least one cutting edge is rotated around a tool axis becomes a line-symmetric and discontinuous line along a parabola, two parabolas, an ellipse or two ellipses. The projected shape is drawn on a projection plane parallel to the tool axis.

Abstract: A cutting tool includes a body including a connecting end, a cutting end which includes a space for receiving the work piece, at least one projection with a ridge defining at least one cutting edge for cutting the work piece, and at least one slot for allowing pieces trimmed from the workpiece to exit from the body. The space has a top and a bottom and tapers outwardly from the top to the bottom. The at least one cutting edge has a first end adjacent to the top of the space and a second end adjacent to the bottom of the space and extends from the first end to the second end obliquely. The body is rotatable about a first axis, and the first axis extends longitudinally between the first and second ends of the body.

Abstract: A drill bit or boring tool having cutting edge that includes a pair of generally smooth curvilinear shaped portions that are positioned near the radial outer portions of the cutting edge and connected to one another by a pair of generally linear portions that traverse the longitudinal centerline of the tool.

Abstract: One aspect of the disclosure relates to a cutting tool for forming a final opening in a stack that includes at least two layers and a pilot opening having a pilot-opening dimension and extending through at least one of the at least two layers. The cutting tool includes a shank. The cutting tool also includes a first portion including at least one of a first coating or the first coating and a second coating, wherein the first coating at least partially covers the first portion. The cutting tool also includes a second portion between the shank and the first portion, wherein the second portion includes the second coating, and wherein the second coating at least partially covers the second portion.

Abstract: A device for internal chips cutting machining in a bore having a unit for breaking up chips by internal chip cutting machining in the bore. The device includes a principal element with a longitudinal axis and with at least one movable cutter head with a cutter that can be moved essentially perpendicular to the longitudinal axis of the principal element. The device also includes a mechanism for linear motion. A nozzle for flushing of the cutter fluid on the cutter is located onto and can be moved together with the cutter head. A fluid duct is in connection with the nozzle and has a source for cutter fluid at high pressure.

Abstract: A rotationally driven multi-bevel step tool comprises a plurality of single- or multi-edged cutting steps arranged in a staggered manner in a cutting and feeding direction, a number of flutes in each step corresponding to the number of cutting edges in each corresponding step, at least one web, and at least one swarf window. Flutes which are adjacent in the circumferential direction in each step are delimited from one another by at least one of the at least one web. The flutes which are adjacent in the circumferential direction, of two successive cutting steps, are connected to one another by at least one of the at least one swarf window, the at least one of the at least one swarf window penetrating the web located therebetween and being open on the circumferential side.

Abstract: A small diameter portion having an outside diameter smaller than a diameter of the drill is formed on a front end side of a body of the drill in which a cutting edge includes at least two portions, that is, a rotation center side cutting edge portion and an outer peripheral side cutting edge portion and point angles of the respective cutting edge portions reducing gradually from the rotation center side cutting edge portion to the outer peripheral side cutting edge portion. The cutting edge with the point angles varied is formed in the small diameter portion. A flat cutting edge having an inclination angle ? of 30° or less with respect to a line perpendicular to an axis of the drill is provided in a step portion formed between the small diameter portion and a large diameter portion.

Abstract: A quadrangular indexable drill insert includes a substantially flat top and bottom surfaces, a side surface adjoining the top and bottom surfaces, four identical cutting edges of the side surface intersecting the top surface, a through hole extending between the top and bottom surfaces, and a chamfer provided at the bottom edge of the drill insert. Each cutting edge includes a first part edge; a second part edge extending from the first part edge; a third part edge extending away from the central axis, the second and third part edges being joined together by a transition part edge having a concave curved portion and a convex curved portion; and a curved nose portion of predetermined radius disposed at a corner of the insert adjoining the first part edge of one cutting edge with the third part edge of a succeeding cutting edge of the four identical cutting edges.

Abstract: The present invention discloses a drill bit 100 comprising a plurality of cutting blade portions 131 for gradually cutting the surface and the inner wall of bones, a plurality of channels 132 for temporarily storing bone chips produced to be agglomerated by the cut bones and for discharging outside the chips, and a working portion 130 having a blocking portion for blocking further approach of the drill bit 100 after it approaches in the bones as much as the length of the plurality of cutting blade portions 131, wherein the plurality of cutting blade portions 131 and the plurality of channels 132 are alternatively formed to have equal interval in circumferential direction, and at least portion of the bone chips produced to be agglomerated in the plurality of channels 132 is located before the plurality of cutting blades 131.

Abstract: The invention provides an end mill having an improved chip discharging performance and capable of carrying out excellent cutting machining. The end mill includes an end cutting edge (2) provided on a front end of a tool body (1) which rotates around a central axis, a peripheral cutting edge (4) provided on an outer periphery of the tool body (1), a rake surface of the end cutting edge (2) and the peripheral cutting edge (4), and at least one recess (6), which locally breaks the continuity of the end cutting edge (2) is provided, wherein a wall section (8) which extends toward the rear of the outer peripheral side is provided at least in that area of the rake surface (3) which is closer to the outer peripheral side than the recess (6).

Abstract: Chips are segmented to have a desired width and the chip controllability is improved and the tool rigidity is improved. A drilling tool is provided that includes: a tool body; a chip discharge groove formed at the outer periphery of the tool body; at least one sub-groove formed at an inner face facing the front side in the tool rotation direction T of the chip discharge groove; a rake face; a tip end flank face; and a cutting edge formed at a ridge line at which the tip end flank face intersects with the rake face. The plurality of rake faces form a step-like shape having at least one step section. The drilling tool is configured so that the turnup section of the sub-groove is turned up in a different direction from the direction along which the turnup section of the chip discharge groove is turned up.

Abstract: A solid step drill, including a front tip and a rear end between which a center axis extends and around which the drill is rotatable in a predetermined direction. At least two cylindrical sections are concentric with the center axis, a first section extending rearward from the front tip and having a first diameter, and a second section extending behind the first section and having a second diameter that is greater than the first diameter, the first section transforming into the second section via a step. The tip includes two primary cutting edges, which individually co-operate with a respective chip flute that is delimited by a concave surface and countersunk in the first section and in the second section, the respective chip flute intersecting the step while forming a secondary cutting edge. Adjacent to the secondary cutting edge, a chip breaking recess is formed between a cutting edge line of the cutting edge and the concave surface.

Abstract: The invention relates to a multiple edge drill such as is especially used for machining difficult-to-machine, e.g. high-toughness materials, such as e.g. cast steel, steel for hardening and tempering or other difficult-to-machine steel materials including metallic cast materials, such as e.g. gray cast iron, and especially GGV or ADI cast iron. The facet is designed in such a manner that the main cutting edge has at least two main cutting edge sections that define point angles of different size, the radially outer point angle being smaller than the radially inner one, thereby obtaining a good cutting behavior and long service life of the tool.

Abstract: A drill insert of the present invention comprises a corner part, and an upper face having a first side and a second side disposed on both sides of the corner part, respectively. The drill insert comprises a first cutting edge formed along the first side; a second cutting edge formed along the second side; a first region of the upper face located along the first cutting edge; a second region of the upper face located along the second cutting edge; and a first raised part disposed in the first region so as to lie at a higher position than the second region. The first raised part has an upper portion; a breaker portion configured to be inclined so as to become at a lower position as the first raised part extends from the upper portion; and a side portion configured to be inclined so as to become at a lower position as the side portion extends from the upper portion. The first raised part is disposed at a position closer to the first cutting edge than a bisector of the corner part when viewed from above.

Abstract: This document provides novel drills and/or reamers that are well-suited for making holes in a variety of materials including, but not limited to, metals, ceramics, glass, wood, plasterboard, plastics, stone, composites, synthetics, silicon or multi-layered or hybridized substrates. In some embodiments, these drilling devices have some centers of mass that are offset from the axis of rotation. Accordingly, such drills and/or reamers may rotate and cut using a precessional pattern of motion. Precessional cutting devices may display a mechanical wave pattern in relationship to the longitudinal axis of the device. If the cutting device is fabricated from a flexible material, for example Nickel-Titanium, bodily deflection of the device may result during rotation.

Abstract: A rock drill bit having a shank fitted with a clamping end and a drilling tip located from the clamping end. The drilling tip has at least three blades and a central zone centered on a drill bit axis. The blades each include on a top side thereof a lip constituted by a leading chipping face and a trailing flank. The lips substantially converge onto each other within a the central zone of the drilling tip, wherein in the central zone, a long lip of the lips runs through the drill bit axis and has a commensurate overshoot segment extending beyond the drill bit axis.

Abstract: A tap for cutting thread production can include a working region that is rotatable about a tool axis, and has a plurality of cutting teeth arranged on the tool circumference, wherein each cutting tooth has a cutting tooth head at a region that is radially farthest from the tool axis. The radial distance of the cutting tooth heads from the tool axis is substantially the same or decreases counter to an intended feed direction of the tool in a guide region of the working region, but increases counter to the intended feed direction of the tool in a starting region of the working region. Thus, in an axial cross section, the superimposed profiles of axially spaced-apart cutting teeth have a profile differential area. The radial cutting tooth profile boundary of the cutting teeth can be at least sectionally curved in the starting region.

Abstract: The invention discloses a drilling tool having at least one chip groove for chip removal, having an insert seat which is formed at the end of the chip groove and serves as a holder for an indexable insert with at least one main cutting edge on the two narrow sides and with at least one secondary cutting edge on the two longitudinal sides of one face side wherein the indexable insert has two face sides facing away from one another and bears with its inactive face side on a holding surface of the insert seat, and a partial region of the inactive secondary cutting edge of its active face side lies in the insert seat at a distance from the adjoining side wall of the insert seat created by a slot, and wherein a guide lip which covers the slot protrudes out of the top side of the side wall in the direction of the inactive secondary cutting edge.

Abstract: A twist drill includes a cutting portion and a drill body. The cutting portion has a chisel edge, a segment relief surface, a chamfer relief surface and at least two flutes extending longitudinally to the drill body. Each flute has a rake surface and a gash extending away from the chisel edge. The cutting portion further has at least two cutting segments, each cutting segment having a first curved cutting edge, a second curved cutting edge and a chamfer cutting edge.

Abstract: A drill bit with high performance for chip removal. The drill bit comprises a cutting tip and a drill body. The cutting tip comprises a chisel edge, a back edge, a cutting edge groove and a rear rib. The cutting edge groove is a circular groove having meniscus shape. A primary cutting surface interposed between the cutting edge groove and the back edge has a trapezoidal or triangular shape. Grinding the rear rib forms a quadratic rear plane. The quadratic rear plane crossing with the chisel edge and the cutting edge groove defines a cutting edge groove plane. The drill bit has three tips and seven cutting edges. A drill bit according to the present invention provides a significant improvement in cutting performance over known twist drill bit in the prior art.

Abstract: A three-way indexable throwaway tip for deep-hole drilling can be used as a center cutting blade body for a drill head in either whole cutting type or uncut core break-off type applications. The throwaway tip for deep-hole drilling is of a thick plate body having a three-fold symmetry with three cutting sections that are rotationally spaced apart at a central angle of 120 degrees. When mounted on a drill head, one cutting section of the throwaway tip faces a drilling direction. The forward facing blade edge of that cutting section includes an inner blade edge shorter in blade length and an outer blade edge longer in blade length forming an apex. The outer blade edge is composed of two consecutive blade edge portions of a peak-side outer blade edge portion having a smaller outer blade edge angle and a corner-side outer blade edge portion having a larger outer blade edge angle.

Abstract: A drill tool including a drill body having an inner insert and an outer insert at an end portion of the drill body. The distance from a central axis of the drill body to the outer insert is greater than the distance from the central axis to the inner insert. The cutting edges of the inner and outer inserts can be chamfered with the inner insert chambered at a radially inward portion and the outer insert chamfered at a radially outward portion. The inner insert and the outer insert can be mirror symmetric to one another. The inner insert and the outer insert are mounted to the drill body such that an effective cutting length of the inner insert equals an effective cutting length of the outer insert, the effective cutting lengths being measured in a direction perpendicular to the central axis.

Abstract: A holder of the present invention has a first insert pocket and a second insert pocket at the tip end thereof. The first insert pocket is located closer to the central axis thereof than the second insert pocket. The axial rake of the first insert pocket is larger than the axial rake of the second insert pocket.

Abstract: An indexable insert for solid drills has four identical cutting edges (30) arranged at a distance above a supporting base (42) and each extending between two cutting-edge corners (28?, 28?). The cutting edges are each bounded by a cutting face (46) and a clearance face (48), with the inclusion of a wedge angle (b). Of the cutting edges (30), one in each case is in an active operating position during the drilling operation. To permit optimum adaptation to the cutting conditions and drilling characteristics, varying over the length of the cutting edge of the drilling tool, it is proposed according to the invention that the height (h) of the four cutting edges (30), measured from the plane of the supporting base (42), and/or the clearance angle (a) varies over the length of the respective cutting edges (30).

Abstract: A drill has inner and outer inserts. The drill includes a drill body having a rotational axis; an inner insert mounted adjacent to the axis at a proximal end of the drill body having an axis-symmetrical contour having four cutting edges and four rounded corners; and an outer insert identical to the inner insert being mounted farther away from the axis than the inner insert. Loci of the inner and the outer insert partially overlap. At the overlapping region, the cutting edge of the inner insert and the cutting edge of the outer insert extend toward the axis in a direction to a workpiece and the locus of the cutting edge of the inner insert protrudes in a direction to the workpiece along the axis of the drill body compared to the locus of the cutting edge of the outer insert.

Abstract: An insert includes a body portion and at least one cutting edge disposed on the periphery thereof. The cutting edge includes an inner lip and an outer lip disposed at an angle with respect to one another. A line extending along the inner lip intersects with a line extending along the outer lip at the vertex of the angle. The angular cutting edge further includes a protuberance disposed between, and connecting the inner and outer lips and projecting outwardly away from the body portion beyond the vertex of the angle defined by the intersection of the lines extending from the inner and outer lips. The protuberance having an inner lip connected to the inner lip of the cutting edge and an outer lip connected to the outer lip of the cutting edge to form smooth curvilinear transitions between the lips of the protuberance and the lips of the cutting edge.

Abstract: An indexable drill includes an insert attachment seat and a chip discharging groove formed so as to extend from a leading end surface to a trailing end side of the drill in the direction of the axis of rotation and through which chips generated by the cutting insert are discharged, and in that a wall surface defining the chip discharging groove at least partly includes a smoothed surface with a surface roughness of at most 0.5 ?m in terms of arithmetic average roughness Ra, the wall surface of the chip discharging groove is partly formed on a thinned wall portion thinned by the central edge attachment seat and the outer peripheral edge attachment seat, and a crossing portion between the first wall surface and the second wall surface in the thinned wall portion is rounded.

Abstract: A drill-reamer tool comprises a shank portion and a cutting portion coaxial with the shank portion, the cutting portion having an operational portion comprising at least one twist drill spiral roughing cutting edge associated with a land margin, a land clearance and a flute. The cutting portion further comprises at least one spiral finishing edge interlaced with the spiral roughing cutting edge and having associated therewith only a land margin and a flute. The land margin of said finishing edge being provided with a plurality of reamer cutting edges spiraling in an opposite direction to that of the roughing cutting edge. The reamer cutting edges being configured to cut a larger hole than said roughing edge. The operational portion being dimensioned such that during operation, both the roughing cutting edge and the reamer cutting edge are simultaneously operative.

Abstract: An indexable drill which has cutting edges formed of a plurality of indexable inserts and which provides stable performance so that the accuracy of entrance hole diameter and exit hole diameter is improved and generation of burrs at the hole exit can be suppressed. Indexable inserts which form a center cutting edge and a peripheral cutting edge are attached to a drill main body at an end thereof. A ratio between a cutting contribution of the center cutting edge and a cutting contribution of the peripheral cutting edge is set such that the cutting contribution of the center cutting edge is larger. The indexable insert is disposed so at to project forward in the axial direction from the indexable insert so that an outer-end corner of the peripheral cutting edge engages a workpiece first.

Abstract: A throwaway drill, an insert provided on the throwaway drill, and a cutting method using the same. The throwaway drill has a throwaway drill holder including an inner edge insert pocket having a seat, formed on a central axis side of a tip end of a drill main body, and an outer edge insert pocket having a seat, formed on the outer peripheral side of the tip end; an inner edge insert fixed to the seat of the inner edge insert pocket; and an outer edge insert fixed to the seat of the outer edge insert pocket.

Abstract: A spade bit includes a shaft defining an axis about which the spade bit is configured to be rotated. The space bit also includes a blade attached to the shaft and having a first paddle portion and a second paddle portion. In addition, the spade bit includes a tip portion attached to the blade and aligned with the axis. The first paddle portion includes (i) a first leading end portion positioned on a first side of the axis and configured to define a first cutting edge portion, and (ii) a first lateral extension portion configured to define a first sloping surface. The first paddle portion defines a first relief space positioned adjacent to both the first sloping portion and the first leading end portion. The second paddle portion includes (i) a second leading end portion positioned on an opposite second side of the axis and configured to define a second cutting edge portion, and (ii) a second lateral extension portion configured to define a second sloping surface.

Abstract: Provided is a step-shaped drill bit including at least two stepped cutting edges that are axially provided. A cutting edge of a first step from a tip is formed so as to satisfy at least one of the following conditions. That is, a number of blades is smaller, a point angle of the cutting edge is larger, or a clearance angle of the cutting edge is larger than that of cutting edges of a second and subsequent step(s). As a result, a thrust resistance during a perforation can be reduced compared with a case in which the first step cutting edge is formed such that the number of blades, the point angle of the cutting edge and the clearance angle of the cutting edge are the same as those of the second and subsequent step(s).

Abstract: A step drill bit comprises a body. A cutting edge insert is removably attached to the body. The body may be made of a first material and the cutting edge insert may be made of a second material where the second material is different than the first material. The cutting edge insert may define a plurality of progressively larger cutting diameters.

Abstract: A helical multilevel cutting tool has high heat emission efficiency, great strength and excellent durability, and can be positioned easily during drilling operation. The cutting tool includes a cutter shank and a cutter head which are integrally formed, wherein the cutter head is provided with several helical pieces integrally, each helical piece has a cutting blade thereon, a heat emission platform is formed along the cutting blade, a second cutting blade which faces forwardly as viewed in the direction of the cutting operation is formed in front of the heat emission platform, and a cutting blade outer surface is formed between the heat emission platform front surface and the second cutting blade. An outer front cutting blade is formed on the top surface of the cutter head at a position where the blade meets the heat emission platform front surface, and a front cutting blade is formed between the second cutting blade and the center of the cutter head top surface.