Abstract: A hole saw has an arbor and a cup shaped cutting member. The cup shaped cutting member has an annular skirt with a plurality of teeth at its free end. A drill bit is secured on the arbor. The drill bit includes a pilot point with a first cutting edge. A second edge is formed on the body portion of the drill bit to form a constant diameter hole in the workpiece.

Abstract: A drill includes a flute and a shank, a feed screw extends axially from an end of the flute. A plurality of first cutting edges extend radially from the flute and are arranged in spiral form. A plurality of second cutting edges are formed on respective tops of the first cutting edges and these second cutting edges are dull when compared with the first cutting edges. Each second cutting edge has a thick support portion connected at a root portion thereof.

Abstract: A spot drilling tool includes a drill holder and an insert removably mounted to the holder. The insert is a standardized part configured to support a drill point in a predetermined position forward of the drill holder and centered on the rotational axis of the drill holder. The drill point has two flutes and two substantially conical land surfaces extending between the flutes. The land surfaces have centers of curvature offset from the rotational axis of the insert to provide radial clearance for the trailing portion of the land. A chisel edge at the tip of the drill point is supported by a tapered web defined between the diagonally opposed and offset flutes. Linear cutting edges are formed at the junction of a planar flute surface and the conical land surface. The cutting edges define a narrow included point angle of between 50° and 80°.

Abstract: A planing apparatus which has an elongated bladelike member having a thickness, a width and a length, which bladelike member is symmetrical about an imaginary central longitudinal axis, and which bladelike member comprises (i) a shoulder portion comprised of two beveled cutting areas and (ii) a body portion forming a leading edge which is convex relative to the body portion. The planing apparatus has an elongated shank member for coupling the planing apparatus to a rotational driver, which shank member is attached to and axially aligned with the shoulder portion of the bladelike member.

Abstract: An elongated drill bit has a shank at one end and working end at the other. A flute portion is between the working end and the shank. The flute portion is continuous with the shank and working end and is generally unitarily formed with them. The working end has a pilot tip with a first cutting portion. A second cutting portion is at the terminus of the flute portion and is axially spaced from the pilot tip first cutting portion. The second cutting portion includes a pair of cutting edges on opposing sides of the pilot tip. Each of the second cutting edges is on an angle from about 22° to 27° to a line transverse to the longitudinal axis. The cutting edges are defined by the junction of a rake face, defined by the flute surface, and a primary clearance face. Also, a secondary clearance face may be present which is continuous with the primary face at a different angle. The angle is about 50° to 65° with respect to the longitudinal axis.

Abstract: A tool bit providing a combined drill bit and reamer is disclosed herein. The tool bit comprises an axial bit shaft including a bore end and a shank end. At least one helical land portion is provided on the bit shaft. The at least one helical land portion includes a cutting edge and a trailing edge. At least one reamer blade is provided on the helical land portion at the bore end of the bit shaft. The at least one reamer blade includes a substantially axial cutting edge. A tip arrangement is also included on the bore end of the bit shaft. The tip arrangement includes a center blade positioned between peripheral cutting blades.

Abstract: A chamfer drill includes a chamfer bit, a sleeve having a unidirectional needle bearing and a strong magnet respectively fitted in a front and a rear end thereof, and a handle associated at a front bore with the rear end of the sleeve. The chamfer bit has a rearward extended shaft, which is extended into the sleeve through the unidirectional needle bearing to end closely in front of the magnet, and is therefore magnetically attracted to the magnet and fixedly located in the sleeve. When the chamfer bit has been turned once to chamfer a drilled hole, an operator can continue the chamfering simply by turning the chamfer bit reversely and then forward again without the need of extracting the chamber bit from the hole being chamfered. And, only one handle is needed for associating with differently sized chamfer bits.

Abstract: A cranial perforator with an inner drill and an outer drill that surrounds the inner drill. Both drills are rotated by a head. Once the inner drill penetrates the bone, the inner drill moves against the outer drill. This movement causes the inner drill to disengage from the perforator head. The disengagement of the inner drill from the perforator head serves to stop the rotation of both drills.

Abstract: The drill bit comprises a cutting blade formed at one end of a shank. The cutting blade has a pair of cutting shoulders that extend inwardly from the outer sides of the blade toward the bit axis. A tip having converging sides that create a point extends from the shoulders. The cutting edge of each shoulder is beveled with respect to the plane of the face of the blade. A flute is provided on the leading portion of each blade face adjacent the cutting edges. Each flute is a smooth curve that creates a substantially uninterrupted recess on each face of the blade that facilitates chip removal, increases the drill rate and lowers the power required to drill a hole. A non-stick coating may be applied to the blade to further facilitate chip removal.

Abstract: A drilling and/or chiseling tool, in particular for machining materials such as concrete, rock, masonry, and the like, having a hard metal cutting element (1) contained in the machining end of the tool head, a radially outer, second working region (II) of the hard metal cutting element (1) being set back in relation to a central, first working region (I) of the hard metal cutting element (1) and the two working regions (I, II) transitioning into each other via a third working region (III). The third working region (III) is at least partially comprised of at least one partial circumference surface (5, 6) of at least one conical surface.

Abstract: Methods and tool for simultaneously forming a bore in a work piece and forming a series of threads in said bore. In an embodiment, the tool has a predetermined axial length, a proximal end, and a distal end, said tool comprising: a shank located at said proximal end; a pilot drill portion located at said distal end; and a mill portion intermediately disposed between said shank and said pilot drill portion. The mill portion is comprised of at least two drill-tap sections of predetermined axial lengths and at least one transition section of predetermined axial length, wherein each of said at least one transition section is sandwiched between a distinct set of two of said at least two drill-tap sections.

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: An embodiment of a spade bit has straight grooves at a lead angle of 4 to 8 degrees placed on flat edges of the spade bit. In an alternative embodiment, a spade bit has two steps of straight grooves at a lead angle of 4 to 8 degrees placed on flat edges of the spade bit. In other alternative embodiments, a spade bit has tapered flat edge which have straight grooves at a lead angle of 4 to 8 degrees placed thereon. The straight grooves on the flat edges of the spade bits allow the spade bit to pull itself through the workpiece with a minimal amount of penetration. The flat edges of the spade bit may also have cutting surfaces for cleaning the hole and permitting the easy removal of the spade bit from the hole after drilling.

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 cutting tool insert having a specialized spur point geometry at the center of the insert. The insert comprises a spur point cutting portion and a blade cutting portion wherein the spur point provides stability by providing a spot and allowing a flexible workpiece to partially spring back when the spur breaks through. The spur point insert facilitates the cutting of relatively thinner workpieces and workpieces requiring the tool to have a longer reach to the hole, while minimizing the burr resulting from the drilling operation.

Abstract: A combination tool for drilling a bore and countersink for that bore includes a countersink member. The countersink member comprises a longitudinal sleeve with a first end and a second end. The sleeve contains a longitudinal bore through the sleeve from the first end to the second end sized to receive a drill bit. A radial slot through the wall of the sleeve is in communication with the longitudinal bore. The sleeve has a cutting edge connected to the first end of the sleeve. A collar containing a radial bore through its wall is slidably inserted over the sleeve. The radial bore is in communication with the radial slot of the countersink member. A fastening mechanism extends through the radial bore of the collar and slot of the countersink member to engage the drill bit inserted through the longitudinal bore of the countersink member and thus secure the drill bit, countersink member and collar relative to one another.

Abstract: A spade bit including a longitudinally extending shaft having a cutting member located at a distal end thereof. The cutting member comprises a pair of helically shaped, opposed blades joined along the longitudinal axis of the shaft and an axially extending pilot spur. The pilot spur defines a pair of cutting edges, and each of the blades defines a forward cutting edge joined with a respective cutting edge of the pilot spur.

Abstract: The present invention provides a unitized replaceable drill bit, and more particularly to a cutting tip of the drilling common bit, in which the central drill has an extended cutting edge, thereby to form a continuous cutting with the side cutting edges so as to prevent the cutting edge from chipping by built-up edge, and make the central drill become smoother and tougher, further to improve cutting property, easy manufacturing and efficiently reducing production cost, and improving competition capability in the market, wherein, integrating the central cutting drill and the level extended cutting edge into one whole body is to widen the cutting range, extend the cutting edge, and prevent chip from building up on the cutting edges and the cutting edges from breaking up; and building up a notch without cutting function on the joint portion of the bevel cutting edge of the central cutting drill and the level extended cutting edge separates said two cutting edges segments so that the cutting resistance may not be

Abstract: The invention relates to a drilling tool (36), in particular for working concrete, rock, masonry and suchlike materials, having a single- or multi-edge tool head with at least one cutting body (1) which comprises a central region (12) which is designed in a roof shape, has rake faces and flanks and is defined laterally by two outer regions (13, 14) set back in the effective direction of the drill. In this case, the ground surfaces of the central region (12) form a pyramidal point (15) while avoiding the formation of a chisel edge.

Abstract: A spade drill bit has a shaft and a spade head portion arranged on the shaft. The head portion has a rearward facing bottom edge, two longitudinal sides and a forward facing cutting edge. The cutting edge has a pointed, generally triangularly shaped tip and outer ends. The longitudinal sides of the head portion are bent along a bend in a direction of rotation of the drill bit during operation, so that the outer ends are bent forwards in the rotating direction. The bend runs from a first position at one of the longitudinal sides, closer to the bottom edge than to the cutting edge, and to a second position at the cutting edge between the outer end and the tip.

Abstract: A drill bit is disclosed having a cutting portion having a plurality of axially aligned, graduated cutting members. Each of the members has cutting edges defined by a single slot extending therethrough. A tip portion at one end of the cutting portion defines at least a pair of cutouts therein, wherein one of the cutouts is aligned with the slot.

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: An elongated kelly valve for use in well drilling equipment is manufactured by a method utilizing a novel drill bar that bores a stepped opening in the valve material in a single operation and with improved accuracy.

Abstract: The present invention to provide a high performance and versatile drill bit, for drilling curved bores, milling, countersinking and other application. A drill bit comprises a crown and a shank extending from the crown, wherein the crown comprises at least three cutting blades.

Abstract: In order to achieve especially low wear of the drilling tool during drilling and permit drilling with a high feed rate, the invention provides a drilling tool (1) having a shank (3) with a first end (5) and a second end (7), at least one of the ends having a drill head (8, 81, 82) with flutes (10), the drill head having at least three lips (9) and a centering cone (11), and the main cutting edges (91) of the at least three lips of the drill head (8, 81, 82) being relief-ground at least in sections, and the centering cone (11) projecting from an area which is described by the cutting edges (91) by rotation of the drilling tool about its shank axis (2).

Abstract: A drill bit for use in association with a power or hand drill comprising a drill bit head and shaft. The drill bit head includes a drill bit cutting head and a guide point. The drill bit cutting head includes a first and a second cutting vane. Each cutting vane includes a first cutting edge which extends perpendicular to the axis of rotation and is provided for removing workpiece material, a second cutting edge which extends parallel to the axis of rotation and is provided for forming a substantially smooth workpiece bore, and a channel for facilitating the expulsion of removed workpiece material away from the first cutting surface as the drill bit passes through the workpiece.

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 step drill minimizes burrs formed during drilling. Reducing the uncut portion of the work minimized an exit burr, which is formed by the advancing of a drill into a workpiece and increases the bending deformation during the drilling procedure of the workpiece and prolongation of cutting without bending to the end of cutting. The step drill includes a step portion formed at the front edge of the step drill. The step portion has a diameter less than a diameter of the body of the step drill and a step angle of 5 degrees through 130 degrees, and the size of the step is preferably 3% to 20% of the diameter of the body of the step drill.

Abstract: A large diameter self-feed wood bit is provided including a feed spur having a coarse spur thread of approximately 1.75 millimeters and a 20-degree main cutting edge relief angle. The main cutting edge relief angle complements the coarse self-feed thread pitch for faster, more efficient drilling of large diameter holes in wood.

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: A tool for removing a tubular member having a threaded exterior, such as a pipe fitting, from a threaded bore. The tool includes a pilot section for guiding the tool into an interior of the tubular member, a shank section adapted for connection to a drill chuck, and a central body for engaging the tubular member. The central body has a cross section transverse the longitudinal axis that is generally circular and that tapers in diameter from the shank section toward the pilot section along an entire length of the central body. At least one flute extends along a helical path on an exterior surface of the central body. The pilot section guides the central body into the interior of the tubular member to grind away the tubular member without damaging the threaded bore.

Abstract: A tool for removing a tubular member having a threaded exterior, such as a pipe fitting, from a threaded bore. The tool includes a pilot section for guiding the tool into an interior of the tubular member, a shank section adapted for connection to a drill chuck, and a central body for engaging the tubular member. The central body has a cross section transverse the longitudinal axis that is generally circular and that tapers in diameter from the shank section toward the pilot section along an entire length of the central body. At least one flute extends along a helical path on an exterior surface of the central body. The pilot section guides the central body into the interior of the tubular member to grind away the tubular member without damaging the threaded bore.

Abstract: A large diameter self-feed wood bit is provided including a feed spur having a coarse spur thread of approximately 1.75 millimeters and a 20-degree main cutting edge relief angle. The main cutting edge relief angle complements the coarse self-feed thread pitch for faster, more efficient drilling of large diameter holes in wood.

Abstract: A spade drill bit has a shaft and a spade head portion arranged on the shaft. The head portion has a rearward facing bottom edge, two longitudinal sides and a forward facing cutting edge. The cutting edge has a pointed, generally triangularly shaped tip and outer ends. The longitudinal sides of the head portion are bent along a bend in a direction of rotation of the drill bit during operation, so that the outer ends are bent forwards in the rotating direction. The bend runs from a first position at one of the longitudinal sides, closer to the bottom edge than to the cutting edge, and to a second position at the cutting edge between the outer end and the tip.

Abstract: A drill bit for boring non-linear holes in a workpiece, the drill bit having a generally elongate post, for mounting the drill bit to a tool; a generally elongate shank; and a head. The head has a front portion, a rear portion and there between a main body portion. A plurality of flutes are arranged in a generally helical shape along the main body portion, arched with respect to a longitudinal direction of the drill bit, each flute having an outer cutting edge arranged on an outside edge of the flute, to provide cutting capability in a direction substantially sideways compared to the longitudinal direction of the drill bit. A central point, arranged on the front portion of the head, is connected to at least one flute via a tapered first cutting portion, the first cutting portion being provided with a first cutting edge, to provide cutting capability in a direction substantially forwards.

Abstract: A drill bit for drilling a hole of a selected diameter in a wood workpiece includes a conically shaped tip having a main cutting portion and a thread series operable to threadingly draw the drill bit into the wood workpiece. The thread series has a diameter which progressively increases in a direction opposite to the drilling penetration direction of movement of the drill bit to a maximum diameter which is the same as the selected diameter of the hole to be drilled. The drill bit also includes a cylindrical portion extending from the conically shaped tip, a spiral screw shaped splinter groove for conducting splinters in the drilled hole away from the drill bit penetration area and a centering drill portion with a self cutting thread series.

Abstract: The present invention provides a method and apparatus for forming a plurality of parts, such as spade-type boring bits, from a continuous stock material. Thus, the various steps of the forming method of the present invention can be performed to predetermined portions of the continuous stock material prior to separating the continuous stock material into discrete parts, thereby enhancing the efficiency of the forming process. The present invention also provides an improved forge for forming portions of the continuous stock material into parts having a predetermined shape. The forge can be designed to provide a clearance region proximate the forward end of the ram to permit slight flexing of the forward end of the ram in a radially outward direction during forging operations. The forge can also include a lubrication system for lubricating its various components. In addition, the forge can incrementally rotate the ram after one or more parts have been forged.

Abstract: A drill bit, includes a shank and a cutter head connected to the shank. The cutter head has a center point, and first and second cutting edges extending radially outwards from opposite sides of the center point, wherein the first and second cutting edges are formed along their radial extension with valleys and peaks in alternating disposition such that in relation to the center point, as viewed in radial direction, the valleys of the first cutting edge are arranged at locations where the peaks of the second cutting edge are disposed, and the peaks of the first cutting edge are arranged at locations where valleys of the second cutting edge are disposed.

Abstract: A modified Forstner type drill bit includes a shank and a drill head. The drill head includes a center brad, first and second radial cutters, first and second following rims and first and second chip channels. The center brad defines a longitudinal direction. The first and second of radial cutters extend radially from the center brad. The first and second following rims extend circumferentially from and following from in the direction of rotation the distal end of the first and second radial cutters respectively. Each following rim is divided into a plurality of segments, each have a top portion. The top portion of the segments of each following rim are generally in the same plane. The first and second chip channels are positioned adjacent to and before in the direction of rotation the first and second radial cutters respectively. The first and second chip channels are between the one of the first and second radial cutter and the second and first following rims.

Abstract: A wood boring drill bit assembly includes a cast cutting head body having a front cutting portion, a rear connecting portion and a central longitudinal axis extending from the front portion to the rear portion. A stem extends axially rearward from the rear connecting portion. A pair of helically-shaped wings extend from the front cutting portion in opposed radial directions along the longitudinal axis. Each wing has an axially forward surface, a side surface, a trailing surface, and a machined cutting edge. The cutting head body has a tapered surface extending from the side surface of each wing to the rear connecting portion near the stem to allow for smooth retraction of the cutting head body from a drilled hole.

Abstract: A bone drill extending along an axis has (1) a stabilizing point with first and second cutting edges which extend to a tip, conical wall sections and flutes on opposite sides of each of the first and second cutting edges and (2) first and second lands extending radially outwardly from the conical wall sections, each land having a radially outwardly extending cutting edge.

Abstract: A drill bit for boring non-linear holes in a workpiece, the drill bit having a generally elongate post, for mounting the drill bit to a tool; a generally elongate shank; and a head. The head has a front portion, a rear portion and there between a main body portion. A plurality of flutes are arranged in a generally helical shape along the main body portion, arched with respect to a longitudinal direction of the drill bit, each flute having an outer cutting edge arranged on an outside edge of the flute, to provide cutting capability in a direction substantially sideways compared to the longitudinal direction of the drill bit. A central point, arranged on the front portion of the head, is connected to at least one flute via a tapered first cutting portion, the first cutting portion being provided with a first cutting edge, to provide cutting capability in a direction substantially forwards.

Abstract: A drill bit for use in association with a power or hand drill comprising a drill bit head and shaft. The drill bit head includes a drill bit cutting head and a guide point. The drill bit cutting head includes a first and a second cutting vane. Each cutting vane includes a first cutting edge which extends perpendicular to the axis of rotation and is provided for removing workpiece material, a second cutting edge which extends parallel to the axis of rotation and is provided for forming a substantially smooth workpiece bore, and a channel for facilitating the expulsion of removed workpiece material away from the first cutting surface as the drill bit passes through the workpiece.

Abstract: The present invention provides a method and apparatus for forming a plurality of parts, such as spade-type boring bits, from a continuous stock material. Thus, the various steps of the forming method of the present invention can be performed to predetermined portions of the continuous stock material prior to separating the continuous stock material into discrete parts, thereby enhancing the efficiency of the forming process. The present invention also provides an improved forge for forming portions of the continuous stock material into parts having a predetermined shape. The forge can be designed to provide a clearance region proximate the forward end of the ram to permit slight flexing of the forward end of the ram in a radially outward direction during forging operations. The forge can also include a lubrication system for lubricating its various components. In addition, the forge can incrementally rotate the ram after one or more parts have been forged.

Abstract: A drill bit, includes a shank and a cutter head connected to the shank. The cutter head has a center point, and first and second cutting edges extending radially outwards from opposite sides of the center point, wherein the first and second cutting edges are formed along their radial extension with valleys and peaks in alternating disposition such that in relation to the center point, as viewed in radial direction, the valleys of the first cutting edge are arranged at locations where the peaks of the second cutting edge are disposed, and the peaks of the first cutting edge are arranged at locations where valleys of the second cutting edge are disposed.

Abstract: A drill bit for drilling a hole of a selected diameter in a wood workpiece includes a conically shaped tip having a main cutting portion and a thread series operable to threadingly draw the drill bit into the wood workpiece. The thread series has a diameter which progressively increases in a direction opposite to the drilling penetration direction of movement of the drill bit to a maximum diameter which is the same as the selected diameter of the hole to be drilled. The drill bit also includes a cylindrical portion extending from the conically shaped tip, a spiral screw shaped splinter groove for conducting splinters in the drilled hole away from the drill bit penetration area and a centering drill portion with a self cutting thread series.

Abstract: A spade drill bit for use in association with a drill having a direction of rotation includes an elongate shank, a spade portion and a center spur. The elongate shank portion has a central longitudinal axis and one end adapted to engage the drill. The spade portion extends longitudinally from the other end of the elongate shank. The spade portion has opposed spaced apart planar faces and each planar face has a leading shoulder edge and a trailing shoulder edge. Each planar face has a leading face portion and a trailing face portion proximate to the respective leading shoulder edge and trailing shoulder edge that are twisted in the direction of rotation. The center spur extends outwardly from the spade portion along the central longitudinal axis. Preferably the center spur has an elongate flute that has a volume that increases toward the spade portion. Preferably a dimple is formed proximate to a corner leading edge which is between the leading shoulder edge and the leading longitudinal edge.

Abstract: The present invention is a drilling system for cutting flat bottomed holes in work pieces. The tool has two opposing angled cutting edges extending from a rotational axis, with the inner portions of these cutting edges extending upwardly to create an overlapping web at the center. The overlapping web strengthens the center portion of the cuttings edges of the tool. The angle at which the inner portion of the cutting edge is inclined can be increased to create a center point on the cutting surface of the tool. The center point adds stability to the tool as it rotates along its longitudinal axis. The cutting edge has a rake surface with a positive rake angle that lessens the forces on the insert and also allows for better formation of chips of stock material being removed. Chip breakers can be cut into the cutting edges of the insert, further aiding in the removal of stock material.

Abstract: A lamina-shaped borepiece (4) for a self-boring fastening element (1) is provided at its front side with cutting edges (5,6) flanked by grooves (7,8) that extend approximately parallel thereto. Indents (9,10) with set-back cutting edges (11,12) are provided in the area of both front cutting edges (5,6), so that a kind of stepped borer is created. The indents (9,10) are formed in the area of the axial extension of the grooves (7,8).

Abstract: A cutting tool assembly which is adapted for use in combination with a drill for cutting a hole in a work piece. The assembly includes a u-shaped blade and a mandrel assembly for fixing the blade to the drill, a dust shield which surrounds the blade and a stabilizer which can be fixed adjacent the blade. In one construction, the blade includes tips which are removably connectable to a wing portion. Also, a coating of wear-resistant material may be applied to the tips so that the blade is self-sharpening during cutting operations.