Abstract: The invention relates to a wood screw having a screw head having a drive configuration, a screw shank which emanates from the screw head and which at least in portions is provided with a thread, and a drilling tip which adjoins the thread, wherein the drilling tip is configured without a thread, wherein the drilling tip has two longitudinal cutters which continue up to a terminal point of the drilling tip and which run so as to be curved in relation to a central longitudinal axis of the screw, and wherein a circumference of the drilling tip between the two longitudinal cutters does not have any further cutters.

Abstract: An improved cutting tool is provided for cutting openings in a patient's jaw so that a dental implant may be inserted therein. The cutting tool includes a tapered pick portion that has a generally flat surface and a radiused surface. The pick portion further includes a cutting blade that extends along at least a portion of the generally flat surface of the pick portion so that the cutting blade is generally opposite from the radiused surface. When the pick portion is inserted into the patient's jaw and rotated, the radiused surface engages a first section of the patient's bone to create at least one micro fracture in the bone while the cutting blade engages a second section of the bone and removes a portion of the bone in the second section.

Abstract: A drill bit for use in forming holes in a printed circuit board (PCB) is disclosed. The drill bit includes a drill bit body having: a drill bit tip at a first end of the drill bit body; a flute winding about the drill bit body in a helix, wherein a helix angle of the flute is between 44 and 46 degrees in the vicinity of the first end and increases with increasing distance from the first end to between 49 and 51 degrees; and a land width of between 0.08 and 0.1 millimeters.

Abstract: A drill bit for drilling into bone, including at least a first, second and third longitudinally extending substantially straight flute blades, wherein the drill bit has an extrapolated outer profile established by rotation of the first, second and third flute blades 360 degrees about a longitudinal axis thereof, the extrapolated outer profile includes a first surface having tangents more perpendicular than parallel to the longitudinal axis, and the extrapolated outer profile includes a second surface having tangents more parallel than perpendicular to the longitudinal axis.

Abstract: A cutting bit adapted to cut wood or metal is disclosed.

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: A counterbore bit having a blade with paired cutting edges along the distal end of the blade and a circular pilot with a serrated cutting edge positioned medially between the paired cutting edges can be positioned over an embedded nail or fastener and activated to free or clear the embedded nail by creating a pair of concentric bores around and about the nail thus facilitating its extraction by conventional means.

Abstract: A drill body for chip removing machining, including a rotationally symmetrical envelope surface and front and rear ends between which a center axis extends, around which the envelope surface is rotatable in a predetermined direction of rotation. A head is formed in the front end that includes two cutting edges, each one of which includes a first part edge and a second part edge. The first part edge is included in a central tip part having a front end portion situated along the center axis. The second part edge extends between a peripheral end point positioned along the envelope surface and a radially inner end point where the second part edge transforms into the first part edge. The two first part edges converge at a positive nose angle (?) in an axially forward direction, and the two second part edges diverge at a negative angle (?) in the axially forward direction.

Abstract: A bit including a shaft defining an axis about which the bit is configured to be rotated. The bit further includes a blade having a first end attached to the shaft and an opposite second end, the blade further having (i) a first blade portion including a first shoulder defining a first cutting edge portion at the second end of the blade, and (ii) a second blade portion including a second shoulder defining a second cutting edge portion at the second end of the blade. The bit additionally includes a frusto-conically-shaped tip portion having an apex and being attached to the second end of the blade. The frusto-conically-shaped tip portion includes threads extending from the apex to a location adjacent to the first cutting edge portion and the second cutting edge portion.

Abstract: A boring bit includes a shank and a drilling head coupled to the shank. The drilling head includes a center tip and a pair of flanges. Each flange includes a cylindrical sidewall section, a cutting edge extending radially outward from the center tip to the sidewall section, a bottom face extending radially outward from the shank to the sidewall section, a rake face extending axially from the cutting edge to the bottom face, a rearward edge extending radially outward from the shank to the sidewall section and defining a boundary of the bottom face opposite the rake face, a spur extending axially from the sidewall section, and a chip channel defined at least in part by the sidewall section. The sidewall section of each flange extends through a sweep angle from the cutting edge to the rearward edge. The sweep angle is between about 30 degrees and about 60 degrees.

Abstract: A spade bit includes a shaft defining an axis, and a blade attached to the shaft and having a first blade portion and a second blade portion. The first blade portion defines a first leading face portion, and the second blade portion defines a second leading face portion. The first blade portion defines a first cutting edge portion, and the second blade portion defines a second cutting edge portion. The first cutting edge portion lies on a first border portion of the first leading face portion, and the second cutting edge portion lies on a second border portion of the second leading face portion. The first cutting edge portion and the second cutting edge portion both lie in a plane P1. An area A1 is bound by the plane P1 and the first leading face portion when the first blade portion is viewed in a first cross section taken along a plane P2 which is parallel to and spaced apart from the axis by a distance D1, and the area A1 increases as the distance D1 increases.

Abstract: A drill bit includes a shaft having a first end portion connectable to a power tool and a second end portion substantially opposite the first end portion. The shaft defines a longitudinal axis extending through the first and second end portions. The drill bit also includes a first generally planar blade coupled to the second end portion of the shaft and defining a first cutting edge extending generally perpendicularly from the axis, a second generally planar blade coupled to the second end portion of the shaft and defining a second cutting edge extending generally perpendicularly from the axis, a third blade coupled to the second end portion of the shaft and defining a third cutting edge extending generally perpendicularly from the axis, and a pilot tip extending from at least one of the first, second, and third cutting edges generally along the longitudinal axis.

Abstract: An insert for a drill, a drill using the insert for a drill, and a method of cutting a work material are provided.

Abstract: A drill body for chip removing machining, including a rotationally symmetrical envelope surface and front and rear ends between which a center axis extends, around which the envelope surface is rotatable in a predetermined direction of rotation. A head is formed in the front end that includes two cutting edges, each one of which includes a first part edge and a second part edge. The first part edge is included in a central tip part having a front end portion situated along the center axis. The second part edge extends between a peripheral end point positioned along the envelope surface and a radially inner end point where the second part edge transforms into the first part edge. The two first part edges converge at a positive nose angle (?) in an axially forward direction, and the two second part edges diverge at a negative angle (?) in the axially forward direction.

Abstract: A drill steel includes a drill bit and a reamer bit. The drill steel rotates the drill bit to form a hole in a work surface and drives forward to insert the reamer bit into the hole. The reamer bit includes a plurality of inserts positioned on a cylindrical drilling surface to ream out the hole by carving channels in the hole interior surface. The inserts include cutting elements that have radiused or arcuate edges.

Abstract: A cutting bit adapted to cut wood or metal is disclosed.

Abstract: A drill bit has a pair of cutting teeth with cutting elements extending from a cutting end portion of the drill bit. Each cutting tooth extends radially, outwardly parallel to a longitudinal axis of the drill steel. The cutting teeth are juxtaposed with one another on the longitudinal axis. Each cutting tooth includes a plurality of raised cutting elements connected to a plurality of lowered edge portions. The cutting elements produce concentric circular channels in the working surface of a rock formation, as the drill bit rotates during the cutting operation. The drill bit also includes a pocket for accumulating and removing dislodged material during the cutting operation.

Abstract: A cutting plate (4) has a working end (20) to engage a workpiece and an axis (8) of rotation. A pair of oppositely arranged first faces (34) are inclined axially rearward from the working end (20) in an axial plane intersecting said first faces (34). A pair of second faces (30) are alternately arranged between the first faces (34). The second faces (30) are inclined axially rearward from the working end (20) in an axial plane (37) intersecting the second faces (30), and a pair of axis parallel front faces (24). Each of the front faces (24) is bound on three sides by a respective first face (34) and the pair of second faces (30). Each second face (30) is inclined radially inward from a transitional edge with a respective rotationally leading first face (34) in a plane normal to the axis (8) intersecting the transitional edge with a respective rotationally leading first face (34).

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 fluteless pyramid point drill for spotting holes for drills having an included angle from 90-160°. The preferred tool is double ended. Another embodiment features the pyramid point on the back end of a penetrating drill. An enhanced pyramid point geometry enables construction from technical ceramics. These embodiments included a notched pyramid, a dual pyramid, a beveled pyramid, and an eccentric pyramid. Another embodiment utilizes a grooved-body hollow pyramid for reaming holes. Geometries for a single sided penetrating drill for drilling hardened materials include a limited flute with a flute depth of ? the drill diameter. Point angle embodiments include a 0-20° primary cutting edge and a steeper relief angle with a negative rake along the edge, a radial edge and steep relief angle with a negative rake along this edge. Additionally a pyramid point may be superimposed on the dual point angle for superior centering guidance.

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

Abstract: A 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 fluteless pyramid point drill for spotting holes for drills having an included angle from 90-160°. The preferred tool is double ended. Another embodiment features the pyramid point on the back end of a penetrating drill. An enhanced pyramid point geometry enables construction from technical ceramics. These embodiments included a notched pyramid, a dual pyramid, a beveled pyramid, and an eccentric pyramid. Another embodiment utilizes a grooved-body hollow pyramid for reaming holes. Geometries for a single sided penetrating drill for drilling hardened materials include a limited flute with a flute depth of ⅓ the drill diameter. Point angle embodiments include a 0-20° primary cutting edge and a steeper relief angle with a negative rake along the edge, a radial edge and steep relief angle with a negative rake along this edge. Additionally a pyramid point may be superimposed on the dual point angle for superior centering guidance.

Abstract: A spade blade drill having blended open notch forms on either side of an apex. The notches transition into elliptical flutes which extend outwardly toward sides of the insert. The elliptical flute profiles inhibit chip curling and packing. The sides incorporate a pair of surfaces having a reduced clearance angle for preventing chip packing. The blended open notches are deep and extend across the entire width of the flutes, enhancing heat transfer surface area and allowing chips to flow along the entire flute surfaces. A plurality of chip splitters extend from the flutes across two relief surfaces. The chip splitters have a rounded profile, inhibiting chips from becoming hung in the splitters.

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 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: An engraving tool includes an end portion extending to a tip, a pair of flutes in the end portion and wall sections between the flutes. The wall sections are ground in the area of the tip to form surfaces having cutting edges and facets disposed at specific angles relative to a plane perpendicular to axis.

Abstract: A tool for rotary chip removal machining includes a cutting head, a retention element and a shank. The cutting head and the retention element comprise overlapping hooks for mounting the cutting head in the shank. The cutting head comprises two integral major cutting edges, each major cutting edge including a substantially straight edge and a convexly curved edge. The convex edge is disposed ahead of the straight edge and extends radially therebeyond.

Abstract: A masonry drill bit having an improved insert geometry, insert orientation, and interface clearance for providing improved drill speed and penetration rate. The drill bit is adapted for use in drilling masonry or other hard, brittle material. The drill bit has an axially elongated body with a leading front end portion and a rear end portion. The rear end portion is adapted to be held by a tool holder. The body has at least one spiral groove cast in its exterior surface substantially along its length. The insert is embedded in the leading end of the body, extending generally diametrically across the leading end of the body, and centered about a latitudinal plane of the insert. The geometric design of the insert, the orientation of the insert relative to the drill bit, and the interface clearance between the insert and the grooves, reduces friction and heat; resists wear, fractures, and abrasive actions of the chips; increases design life of the elements; and enhances debris elimination.

Abstract: A self-drilling and thread-forming screw comprises a threaded shank, a drilling section arranged in front of the shank and having a uniform diameter, and a thread-free flow-forming section widening conically between the drilling section and the shank. The drilling section has two chip grooves which run diametrically opposite one another, are bounded by flute edges and cutting edges, and end in a drilling tip with the cutting edges running together at the tip. The diameter formed by the cutting edges is smaller than a minor diameter of the threaded shank, and the largest diameter of the flow-forming section corresponds to the minor diameter of the shank and includes a symmetrical polygonal cross-section with rounded-off corners in a region adjoining the shank.

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 a number of discrete parts. The efficiency of the forming process is enhanced since individual parts need not be individually transported and oriented during the forming operations. By not requiring that the individual parts be separately transported and oriented during the forming operations, the quality of the parts formed by the forming method and apparatus of the present invention will also be enhanced since such separate transportation and orientation of individual parts generally increases the opportunities for misalignment and contributes to poor tolerance control during the manufacturing process.

Abstract: A driven part of a tool is secured to a drive part of a drive spindle rotatable about an axis by a mount having a tubular extension projecting axially forward from one of the parts and formed centered on the axis with a radially inwardly projecting collar and a recess on the other part complementarily engageable axially over the tubular extension. A retaining element in the tubular extension has a plurality of dogs deflectable radially between an outer blocking position axially behind the collar and an inner position radially rearward of the collar. An actuating member in the retaining element in the tubular extension has a camming edge engageable forward with the dogs.

Abstract: A self-calibrating countersink tool includes a reusable insert-holder with an axis-defining shank portion and an insert-receiving notch disposed at one end of the holder. The tool also includes at least one selectively attachable insert which is sized and shaped to be received within the insert-receiving notch of the holder. Each disposable insert includes a tapered cutting-edge portion and a notch-mating portion which is complementary in shape to the insert-receiving notch. When the insert is in mating engagement with the holder, the cutting-edge of the insert is disposed forwardly of the holder and defines an angle of between about 105 and 165 degrees relative to the holder axis. The countersink tool also includes an affixation means for affixing a disposable insert to the holder such that the insert is in mating engagement with the insert-receiving notch.

Abstract: The spade-type boring bit includes an elongate shank defining a central longitudinal axis and a blade portion joined to one end of the shank and including a pair of generally flat side segments extending laterally from the central longitudinal axis. Each side segment includes a respective forward cutting edge which are aligned with each other along a centerline which passes through the central longitudinal axis of the elongate shaft so as to increase the efficiency with which the spade bit drills. The spade bit also includes a spur joined to and extending axially from the forward end of the blade portion. The spur can include spur cutting edges separated radially, angularly and, in some instances, longitudinally or axially from the forward cutting edge of the adjacent side segment to prevent accumulation of chip swarf between the spur cutting edge and the adjacent forward cutting edge.

Abstract: The spade-type boring bit includes an elongate shank defining a central longitudinal axis and a blade portion joined to one end of the shank. The blade portion includes a pair of generally flat side segments extending laterally from the central longitudinal axis and having a respective forward cutting edge and a respective chamfered corner portion. Each chamfered corner portion includes a chamfered edge which extends both axially rearward and laterally outward from the respective forward cutting edge so as repeatedly cut the peripheral wall of the resulting hole as the spade bit is rotatably advanced through a workpiece. The spade bit therefore produces a high-quality hole having a smooth peripheral wall and relatively clean entry and exit points. In addition, the forward cutting edges of the spade bit can be aligned with each other along a centerline which passes through the central longitudinal axis of the elongate shaft so as to increase the efficiency with which the spade bit drills.

Abstract: A diamond drill consists of a core and a pair of abrasive diamond tips which are joined to constitute a diamond tip and core assembly in the form of a flat plate. The diamond tips have chamfering sections for providing a cutting blade of a diameter smaller than that of a cutting blade provided by finishing blade sections thereof. The chamfering sections can be used not only for chamfering an edge of a glass plate defining an opening but for cutting a non-circular opening. In another embodiment, an abrasive diamond ring is installed on a shank and used for chamfering an edge of a glass plate defining an opening or for cutting a non-circular opening having a small corner.

Abstract: A cutting plate for a ball-head finish miller has a support body of hard metal centered on an axis and having a pair of oppositely directed and symmetrically oriented faces each formed with a respective substantially circularly segmental recess of a predetermined depth. A pair of substantially identical and substantially circularly segmental cutting inserts are each secured to a respective one of the faces in the respective recess and each have a respective cutting layer forming a cutting edge. The inserts and their edges are symmetrical with respect to the axis and are each of a thickness substantially less than the depth of the respective recess so that each forms a chip cavity on the respective face.

Abstract: A diamond coated drill bit capable of drilling small holes and then reaming the holes to their correct size. The tapered tip of the drill bit has a coarse diamond grit coating which enables it to initiate a hole. The drill bit then gradually grinds the hole to the proper size with a grinder having coarse diamond grit bonded to its surface which is at a predetermined taper. The final diameter of the hole is controlled by using a fine grit diamond reamer above the tapered grinder portion. The grinder applies a radial load to the composite material resulting in no fiber breakout or splintering. The tapered grinder and the reamer are formed on a machined-flat portion of the drill bit which enables coolant to circulate down to the grinding area and allows the easy removal of debris.

Abstract: A spade-type drill bit is disclosed having a shank portion and a spade bit portion extending from the shank portion. The spade bit portion includes a spade portion with a planar region, and a center tip concentric with a longitudinal axis and extending from the spade portion. First and second radial cutting edges extend from the center tip toward first and second corner tips. First and second longitudinal cutting edges extend along longitudinal sides of the spade portion and terminate at the first and second corner tips. The first and second corner tips are located forward of the plane of the spade portion in the direction of rotation of the drill bit. The first and second radial cutting edges, and the first and second longitudinal cutting edges further include curved portions adjacent each of the first and second corner tips. Threads may also be provided on the center tip.

Abstract: A flat drill for boring holes through hard metals and high heat resistance materials such as hard metal and fiberglass. The flute or fluid portion forms a spade with slightly cylindrically concave faces which tend to distally converge. The cutting edges at the base of the drill have a negative rake angle, but a relatively high clearance for this type of drill. The lateral leading edges have a positive rake angle, but are strengthened by cylindrically convex flanks. Nose splits form a small but relatively keen small central burrowing edge which stabilizes the drill.

Abstract: A bone drill bit for drilling a hole through bone, cartilage and/or other soft tissue, and the like includes an elongate cylindrical shaft having a pointed tip at one end and a shank at the other end which is adapted to be received in a surgical drilling apparatus. A plurality of small protuberances are provided around the cylindrical shaft adjacent the tip so that as the protuberances pass through the drilled bone a hole slightly larger than the shank is produced and thus the shank passes freely through the drilled hole. Preferably, the protuberances are diamond shaped and the pointed tip is pyramidal shaped. In addition, a suture holding device, such as an aperture or hook at the end of the shank, is provided for holding a suture to the shank as the shank passes through the drilled hole. A portion of the shank is cut away on either side of the suture holding device to provide clearance for the suture. Where the suture holding device is an aperture, this aperture is preferably countersunk at both ends.

Abstract: A bit (12) has a triangular drill portion (14), a frustoconical grinder portion (24), and a cylindrical reamer portion (28). The drill portion (14) has three longitudinal cutting edges (16) that define the angles of its triangular cross section. The grinder portion (24) extends axially inwardly from the drill portion (14) and has a minimum diameter less than and a maximum diameter greater than the maximum diameter of the drill portion (14). The reamer portion (28) is an axial continuation of the grinder portion (24). The outer surfaces of the grinder and reamer portions (24, 28) are plated with diamond grit (30) to enlarge and finish a hole produced by the drill portion (14). The relative diameters allow the grinder portion (24) to gradually engage the sidewall of a hole. The bit (12) is supported and centered in the hole by three point contact between the cutting edges (16) and the hole sidewall.

Abstract: A drill bit having an elongated, stiffly flexible shank and integral, hardened, enlarged cutting head and tip is adapted to maintain a penetration angle through a plurality of spaced wooden objects while being rotatably driven by a drill. The tip of the drill bit forms a portion of a cutting head and is of generally triangular shape having two relatively enlarged opposed flat surfaces joined by two tapered surfaces. The tapered surfaces intersect at a tip edge defined by a line which makes an acute angle with a plane bisecting said drill bit along the longitudinal axis thereof, and which plane is perpendicular to the flat surfaces.

Abstract: There is provided a hand held and hand operated drill for installing ceiling hooks or other mounting apparatus to a ceiling constructed of plasterboard. The present device collects the falling material cut away by the drilling process in a collection cup mounted on the drill. The device is a one piece plastic molded tool having a handle portion for applying pressure and a reciprocal rotation, a collection dish mounted to a shaft, and cutting blades tapered to a point and honed to an edge for scraping during the reciprocal rotation.

Abstract: A tapping screw includes a screw head, a self-tapping thread portion and a drilling point. The drilling point has a pair of approximately axially extending flutes which are located diametrically opposite each other relative to the shank axis and include clearing surfaces and cutting surfaces. The cutting surfaces end in cutting edges facing the point of the screw and lateral outer knives. Immediately adjacent the cutting edges or cutting knives, the cutting surfaces have a convexly arched cross-sectional shape.

Abstract: The invention provides a specialty tool useful for cleaning out broken off or cut off plastic pipe and glue in plastic fittings and plastic couplers. An arbor for use with a manual or electrical operated drill is provided with a smooth portion and a threaded portion. The threaded portion terminates in a screw head. Positioned on the arbor adjacent the screw head is an internal guide disc sized to fit inside the broken off or cut off plastic pipe to be removed from the plastic fitting or coupler. A circular cutting head having sharpened protrusions along the circumference is positioned next to the internal guide disc. A retaining nut slipped down over the smooth arbor shaft is tightened down against the circular cutter and retains both the cutter and the internal guide disc firmly on the arbor shaft. The assembled device is useful for the removal of broken off or cut off plastic pipe remaining in an otherwise useable plastic fitting or coupling.

Abstract: A cutter insert of the indexable type for a rotary cutter includes a body of a plate of a generally circular shape and having three notches of a V-shape formed in a circumferential face of the body in equally circumferentially spaced relation, each V-shaped notch being defined by a pair of first and second opposed walls. A front face of the body cooperates with the circumferential face, interrupted by the three V-shaped notches, to define three arcuate convex cutting edges each having a leading and a trialing end. A marginal portion of the front face disposed adjacent to and extending along each cutting edge serves as a rake surface for the cutting edge, the rake surface being recessed adjacent to the first wall of the V-shaped notch so as to slope toward a rear face of the body toward the first wall to provide a convex portion extending between the front face and the first wall.

Abstract: A self-cutting fast construction screw for the fastening of fiber plates to a metal substructure carries on the screw shaft at least one turn of a thread. The screw core passes into a conical drill point. On the conical drill point two cutting edges are arranged in a symmetrical layout, said cutting edges cutting to a diameter located between the diameter of the screw core and the diameter of the outer thread tip. Upon impact on the metal substructure, the two cutting edges break off.

Abstract: A drill screw having an integral driving shank, head, and entering end portion. The shank has formed on it thread convolutions of uniform outer and root diameters. The entering end portion has a cylindrical portion coaxial with the shank provided with two flutes inclined with respect to the center axis of the cylindrical portion and disposed on opposite sides of it, and end surfaces of roof-shape. Each of the flutes includes conical flute surfaces. The intersection of each of the conical flute surfaces and each of the end surfaces forms a cutting edge. And each of the conical flute surfaces forms a rake angle with respect to one of the cutting edges, while each of the end surfaces forms a relief angle with respect to one of the cutting edges.In a preferred construction each fluted surface is located outside or beyond a plane containing the center axis of the drill screw, and the fluted surfaces each have a vertex angle of 35.degree. to 54.degree..

Abstract: A drill bit of the multigroove type has a shaft with at least three flutes forming respective lateral cutting edges and as many generally radial frontal ridges, one of them extending to or possibly beyond the shaft axis while the others terminate short of same. Each frontal ridge forms an outer and an inner cutting edge adjoining each other at an obtuse angle in a forwardly pointing peak, these peaks lying at different distances from the axis. The peak closest to the axis is axially foremost and the corresponding inner cutting edge includes the smallest angle with the axis to act as a centering blade; with more than three ridges this centering blade can be duplicated in diametrically opposite positions. The outer cutting edges all lie on a common conical surface centered on the axis.