Abstract: An apparatus and method for cutting a hole in a liner installed in a conduit. Included in the apparatus is a carriage and a cutting head that are rotated to cut the liner. A lateral axis extends through the carriage. A skid constrains the carriage and the cutting head. The cutting head is substantially positioned over the center of gravity of the carriage to provide stability during cutting. The cutting head moves vertically with the use of a cam. The cutter also moves laterally and may rotate about the axis when cutting the hole. Prior to cutting the hole, the skid extends outward to hold the carriage in place. The apparatus also includes a specialized cutter having cutting bars along its outside perimeter and along its top surface.

Abstract: A burnishing drill includes a cylindrical shank and a drill body connected to the shank. Drilling edges, reaming faces and reaming edges are formed on a first reduced-diameter portion, a second reduced-diameter portion and a third reduced-diameter portion located at a foremost end of the drill body respectively. The reaming faces which are located axially at backward positions of the drilling edges and the reaming edges extend radially outward from the foremost end of the drill and incline axially in the rearward direction, and also extend radially outward and incline in the rearward direction with respect of the rotational direction. Since an inner surface of the hole drilled and reamed by the drilling edges and the reaming edges can be further smoothed by the reaming faces, the surface roughness of the finished hole can be much improved.

Abstract: An indexable insert drill for producing a hole in a workpiece by relative rotary motion between the drill and workpiece. The drill comprises an elongated body having a central axis and a leading end, and a plurality of cutting inserts mounted on the leading end of the body. The cutting inserts are displaced at different radial locations relative to the central axis of the body. Each cutting insert has a cutting edge formed by a pair of respective inside and outside active cutting edge segments with the inside cutting edge segment being located closer to the central axis of the body than the outside cutting edge segment thereof. The inside and outside cutting edge segments of the respective cutting inserts extend at obtuse angles to one another and define therebetween apexes which are axially displaced at different distances from a plane normal to the central axis of the drill at the leading end of the drill which distances increase in length from an innermost one of the inserts to an outermost one thereof.

Abstract: A drill and trimming attachment assembly is disclosed for drilling holes with beveled top openings in a work piece. The assembly includes a drill shaft with at least one longitudinally extending groove formed therein. A trimming attachment suitable for clamping to the drill shaft is also provided to form a beveled recess at the top of a hole formed by the drill. The trimming attachment includes a body and a trimming blade having base and arm portions. The base portion of the trimming blade is detachably secured to the body, and the body is arranged to be removably journaled about and clamped to the shaft of the drill such that an edge of the arm portion of the trimming blade is closely received by the groove. Thus, during use, the groove carries at least a portion of the load acting against the trimming blade.

Abstract: A hole reamer takes a rough, undersized hole to final size while providing better correction of any initial axial mislocation of the hole. A pair of cutting sections, a smaller diameter lead cutting section and a larger diameter trailing cutting section, are axially separated by a relieved section of smaller diameter. The relieved section is small enough in diameter that it does not make contact with the hole, and is longer axially than the hole is thick. When the lead section enters the hole, it is bent off axis slightly, but the reamer shifts back on axis when the relieved section enters the hole. Thus, the trailing, final hole sizing section is back on axis as it works to finish the hole, bringing it closer to the desired axial location.

Abstract: A twist drill has a cutting member at the bottom, a shaft at the top, and a reduced-diameter root clearance region between the cutting member and the shaft. Cutting edges are provided at the transition between the cutting member and the root clearance region, and further cutting edges are provided at the transition between the shaft and the root clearance region. After a throughhole has been drilled using the cutting member, the drill is displaced laterally and moved along a circular path while it is still rotating. As a result, the cutting edges at the transition between the cutting member and the root clearance region countersink the bottom end of the throughhole. A similar procedure is employed to countersink the top end of the throughhole using the further cutting edges at the transition between the shaft and the root clearance region.

Abstract: A drill is provided having a generally cylindrically shaped body. The body has a rear end structured to releasably connect with a torque transmitting machine in a conventional manner. The body has a forward end which is provided with diametrically opposed seats. Each seat releasably retains a cutting insert. Each cutting insert has a cutting edge projecting forwardly from the forward end of the body. Further, the cutting inserts are oriented so that one cutting edge is at a ten degree positive lead angle and the other cutting edge is at a five degree negative lead angle, the angles being measured normal to the center line of the drill. In operation, the drill is used to provide a bore hole in a workpiece, the bore hole having a predetermined perimeter. As the rotating drill contacts the workpiece, the cutting edges contact the workpiece in a predetermined, progressive manner which thereby creates a plurality of spaced apart circular notches of differing depth in the workpiece.

Abstract: A combined hole cutting and chamfering tool is provided that in a preferred embodiment referenced by numeral (100) features a body member (2) having a lead section ("A") to which is secured a cutting bit (4) having a machining element such as a hole cutting edge (6). Spaced axially from section ("A") is a chamfering section ("B") having at least one chamfer machining element such as cutting edge (12) of a cutting bit (14) facing towards section ("B") and at least one chamfer machining element such as cutting edge (8) of cutting bit (10) facing away from section ("A") and closer thereto than cutting edge (12). Tool (100) is operative to cut a hole (18) through a workpiece such as a plate and then chamfer edges surrounding the hole on opposite sides of the workpiece from one side without having to remove tool (100) from hole (18).

Abstract: A high speed burnishing drill having drilling edges and reaming edges provided at the forward end of a cylindrical drilling body. The drilling edges are inclined diametrically from the center of the forward end to the axially rearward direction, while the outermost peripheral wall of the drilling edges are on a reduced-diameter portion of the maximum external diameter of the drill body. The reaming edges extend from the plane intersecting the drilling edges radially from a position inward of the outermost peripheral of the drilling edges, outwards, so as to incline axially in the forward direction with a second cutting angle. A reduced diameter portion extends axially backward from the outermost peripheral wall of the drilling edges. An enlarged-diameter guide face extends axially from a slope behind the corresponding drilling edge in the rotational direction, and the forwardmost end of the enlarged guide face is located axially behind the corresponding reaming edge.

Abstract: A burnishing drill includes a cylindrical drill body connected at its forward end integrally with a shank. The forward end of the drill body includes a first pair of cutting edges inclined radially and rearwardly from the forwardmost central end of the drill body toward the shank at a first cutting angle. A second pair of cutting edges formed of diamond chips are disposed in a plane intersecting the plane in which the first pair of cutting edges are located. The second pair of cutting edges are inclined radially and rearwardly from a position inside a circle including the maximum external margins of the first pair of cutting edges toward the shank at a second cutting angle.

Abstract: A cutter for a downhole milling or cutting tool and a tool incorporating the blade has a longitudinal axis about which the tool is rotatable. The tool may have a plurality of circumferentially disposed blades which are either fixed or radially movable to perform a cutting operation. Each of the cutters has a blade having a cutting surface which is formed by a plurality of cutting elements. Each of the cutting elements has a cutting edge and a plurality of protruding ridges each of which are longitudinally spaced from one another and interspaced from one another by a recess portion so that in use swarf moves upwardly from a first cutting edge along the recess portion and is broken off when approaching the next, uppermost, ridge. By providing such relatively closely spaced ridges generally C-shaped swarf cuttings are produced and "birdnesting" is substantially reduced or eliminated. The cutting elements each have a cutting surface which presents a negative radial rake angle.

Abstract: A method and apparatus for removing metal from a workpiece so as to form an incomplete hole therein is disclosed. The tool includes a shank having a plurality of cutting inserts adjustably attached to one end thereof. The cutting inserts are axially spaced apart from one another along the tool shank by a predetermined distance which is greater than the thickness of the workpiece. The first cutting insert functions as a drill or end mill to form a rough incomplete hole through the workpiece, while the second cutting insert functions as a boring tool to finish the incomplete hole. An opposite end of the tool shank is retained within a bore formed in a tool holder. The tool holder is supported within a conventional rotational means, such as a lathe. Both the opposite end of the tool shank and the bore formed in the tool holder are formed eccentrically to provide maximum flexibility in adjusting the rotational axis of the cutting inserts and, therefore, the diameter of the incomplete hole being formed.

Abstract: Piston wrist pin boring tool including semi-finish and finish inserts mounted in individual cartridges adjustably secured in cartridge pockets provided in the boring bar. A carbide shank is brazed to a body provided with a cartridge pocket, and a diamond tip for the finishing insert is provided with a closely controlled flat neutral rake cutting edge supplied with coolant from central passages through the bar.

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 self-drilling and thread forming fastener for fasting a first softer workpiece, such as wood, to a second harder workpiece, such as metal, is described. The fastener features wings of improved configuration including positive angle of attrack, positive cutting edge relief angles, teardrop-like crescent shape across section and knife-like cutting edge which exhibit faster drill times through wood.

Abstract: For drilling a hole and machining at least its opening end without changing tools, a through-hole is drilled using a special tool, and then the same tool is moved sideways by means of a special chuck which guides the tool during machining of the drilled hole. The chuck has a locking means which when engaged holds it in a drilling position and which when disengaged allows sideways motion of a tool mounted in the chuck. The longitudinal section of the tool used, to be located within the hole during the machining operation, is situated within a curved surface having a radius just as great as that of the drill and having its center of curvature on the line about which the tool rotates during drilling.

Abstract: An apparatus for milling away tubular conduits encased within well bores is disclosed. The milling device consists of a cylindrical body. The body forms longitudinal slots therein for radially disposed replaceable cutter blades that are inserted through the slots from the inside of the body. A central mandrel mechanically locks the replaceable blades between the mandrel and the tubular body. A finned pilot head or guide is affixed to the downstream end of the milling apparatus, the opposite threaded upstream end is adapted to be connected to a drill string.

Abstract: A twist drill having a longitudinal axis, a shank portion sized and shaped to be grasped by a twisting tool, and a barrel portion for cutting a workpiece. The barrel portion has a number of flutes formed therein spiraling about the axis and terminating at a point end of the barrel portion. The point end has a number of point surfaces including an inner flank surface, an outer flank surface, a groove surface positioned between the inner and outer flank surfaces and a split surface. The inner flank surface extends from the center of the point end to the inner extent of the groove surface and the outer flank surface extends from the outer diameter of the point end to the outer extent of the groove surface.

Abstract: A drill head assembly for drilling holes in bony structure is disclosed. The assembly has an inner drill and an outer drill which rotate together as a unit. The leading portions of the outer drill are contiguous with the peripheral portions of the inner drill, and the inner and outer drills are adapted to form a bore-countersink opening in the bone, whereby the drill head assembly may be used to safely drill through relatively thin bone.

Abstract: There is disclosed a boring tool which exhibits a cutting head with several cutting plates arranged on the periphery of the cutting head. Each of the cutting plates are pressable with a fastening device against a shoulder of the cutting head. The distances of the cutting plates from the longitudinal axis of the cutting head are slightly different. The cutting heads are staggered with respect to one another in the direction of the longitudinal axis. The cutting plates (1, 2, 3) are formed in a circular shape and are arranged so that the force exerted during operation of the cutting head by the cutting plates compensate each other. The effective cutting edge sections, projecting in an axial plane, continually blend into one another. The boring tool is particularly suitable as a fine boring tool for the production of precision bores.

Abstract: A fabric fastener adapted for fastening a fabric to a framework, or a workpiece to a fabric covered framework, comprises a head and shank, and a sharp edged tip section. The tip section has an unthreaded angle side which intersects a threaded side to form the sharp edge. Preferably two prongs with a space therebetween and sharp edges facing the space are formed at the end of the tip. The sharp edges, particularly of the prongs, serve to engage and cut through the threads of a fabric so that the fastener does not become entangled in the fabric, thereby minimizing damage to the fabric and also minimizing cross-threading with a framework aperture into which the fabric fastener is fastened.

Abstract: A cutting tool for forming an opening in an object, such a steel belted tire or the like, is disclosed. The cutting tool is provided with a relatively small number of first helical grooves in its body portion, and a relatively large number of second helical grooves. The first and second sets of grooves are oriented in opposite directions relative to the longitudinal axis of the cutting tool. The tool so constructed is durable and capable of providing quick and clean operation in forming an opening in the said object.

Abstract: Boring bar having plural circumferentially spaced cutting inserts with incremental radial and axial spacing for innermost radial and foremost axial to outermost radial and rearmost axial in progressive sequence relative to the direction of rotation.

Abstract: A burnishing drill having a drill body, the forward end of which is formed with a reduced-diameter portion having its external diameter smaller than the maximum external diameter of the drill body. The forward end of the drill body includes a pair of first cutting edges formed in the reduced-diameter to include with a first cutting angle, and a pair of second cutting edges formed to extend radially in a direction perpendicular to the first cutting edges at least from the inward position of a plane including the outermost peripheral walls of the first cutting edges to the position of another plane including the outermost peripheral wall of the drill body.Each of the first cutting edges extends radially outward from the center of the forward end of the dril body and includes axially in the rearward direction while each of the second cutting edges inclines extends radially outward from the drill body and inclines axially in the forward direction.

Abstract: A drill/reamer bit has a drill portion formed by cutting edges at the end of a plurality of flutes. A reamer portion is contiguous with the drill portion and includes a first relief formed on each flute surface disposed at a predetermined angle with respect to the flute surface to form a first reamer cutting edge. A second relief is formed contiguous with the first face on each reamer portion and is disposed at a second angle, less than the first angle with respect to the flute surface. Preferably, the angle of the first reamer relief is substantially 30.degree. and the angle of the second reamer relief is substantially 10.degree..

Abstract: A tool in the form of a tapering borer or reamer has cutting portions adjacent the body of the tool with chip-receiving grooves therebetween, arranged alternately around the periphery of the tool. The cutting portions and the grooves may be of a helical configuration or may extend in a straight configuration parallel to the longitudinal axis of the tool. Each cutting portion has a cutting face and a relief face which intersect at a cutting edge. The cutting face defines a rake angle with respect to a first reference plane while the relief face defines a relief angle with respect to a second reference plane which is normal to the first reference plane.

Abstract: A chamfering reamer for reaming the inside diameter of pipe or conduit comprises a generally cylindrical body having a truncated conical forward end to be received within the inside diameter of a pipe or conduit and a rearward end adapted to be secured in a chaser holder of a threading machine and a plurality of longitudinal flutes extending rearwardly from the forward end defining a plurality of circumferentially spaced longitudinal wings. Each wing has a conical reaming portion to ream the interior diameter at the end of the pipe or conduit and a conical trip shoulder extending from the conical reaming portion to the outer surface of each wing to activate the chaser holder to release the chamfered piece and provide clearance between the end surface of the pipe or conduit being reamed.

Abstract: A drill for stack drilling comprises a drill body, a central cutting insert, and a peripheral cutting insert. The inserts have active cutting edges arranged such that the drill successively cuts radially outwardly from the center of the drill in order to avoid the formation of break-out slugs. The active cutting edge of the central insert has three cutting edge portions forming obtuse angles with one another. The radially innermost one of those cutting edge portions is shorter than each of the other two cutting edge portions.

Abstract: In a drilling tool for drilling in solid metal material, in particular for drilling in plate stacks (plate drill), two geometrically similar reversible carbide tips (2, 3) are arranged at different radial distances at the end of the shank (1) and offset from each other by 180.degree. in the circumferential direction, whose working ranges overlap, and each of which comprises several cutting edges (2a, 2b, 3a, 3b) of equal length. Of the cutting edges (2a, 2b, 3a, 3b), respectively two adjacent cutting edges at an obtuse angle (.alpha.) to each other are simultaneously in contact, wherein the radially inner, first reversible carbide tip (2) extends by its cutting edge (2b) which is in contact slightly beyond the drill axis (A), and the radially outer, second reversible carbide tip (3) is axially set back from the first reversible carbide tip (2), and its two operative cutting edges (3a, 3b) form acute angles (.beta.1, .beta.2) of different size with the drill axis (A).

Abstract: A combination drilling and skiving tool including a longitudinally extending hollow skiving sleeve slidably and concentrically mounted on a right-handed twist drill. Dogs or pawls provided on the internal periphery of the skiving sleeve engage with the helical grooves of the drill. During a clockwise rotation of the tool, the drill moves downwardly and the sleeve translates upwardly, so that the drill performs a drilling operation on a workpiece. On the other hand, the drill moves upwardly and the sleeve translates downwardly, when the tool is rotated in a counter-clockwise direction, and the sleeve performs a skiving operation. The drilling and skiving operations are separate, independent and exclusive of each other.

Abstract: A combination drill and screwdriver device for use in forming holes in wallboard material or the like and for driving screws. A Phillips head screwdriver bit is modified for use in forming pilot holes for screw anchors and for a counterbore. A sleeve surrounding the bit provides a drill stop when drilling holes for screw anchors. The sleeve may be pushed through the pilot hole to position a counterbore used for forming larger holes.

Abstract: A cutter for the deburring of bores comprises a rectangular edged cutter element having taperingly extending cutting edges, having clearance surfaces ground undercut and comprising a convexly ground contact surface on one end of the cutter head for contact with the internal surface of a bore. Two oppositely aligned cutter elements are mounted for displacement in a radial direction in a guide recess of a tool holder, and while in the operative position during the deburring of a bore, the cutting elements are displaced inwards radially because of the tool holder feed and because of the tapered extension of the cutting edges, against a spring force in the guide recess, until they finally reach the inner area of the bore in the non-cutting mode.

Abstract: A drill provided with means for effecting a secondary cutting function, such as chamfering, counterboring and/or countersinking. The drill (10) comprises chip flutes, lands (14) and a cutting tip (11). Said means comprise a cylindrical tooth (12) provided with a cutting edge (13) and a pin (17). The land (14) is provided with two holes (15,18) which receive the tooth and the pin.

Abstract: A boring tool and a method of operation are provided for boring two concentric holes of precision diameters and depths in a single operation. The boring tool includes an elongated tool body, a shank for attachment to a standard adjustable boring head which is used on a manual or numerical control milling machine and first and second diametrically opposed cutting edges formed for cutting in opposite directions. The diameter of the elongated tool body is substantially equal to the distance from the first cutting edge tip to the axis of rotation plus the distance from the second cutting edge tip to the axis of rotation. The axis of rotation of the tool is spaced from the tool centerline a distance substantially equal to one-half the distance from the second cutting edge tip to the axis of rotation minus one-half the distance from the first cutting edge tip to the axis of rotation.

Abstract: The present invention includes a tool and method for resurfacing a housing facing. The tool is adapted for use with a rotatable shaft extending from a housing, e.g. an impeller shaft of a pump. The tool includes a body having first and second halves that are removably secured to the rotatable shaft. A plurality of cutters are receivable within slots selectively disposed along the radii of the body halves. Advancing and locking screws for each cutter are utilized to position a cutter for engagement with the housing facing. The shaft is rotated, causing the cutters to produce a cut of desired depth in the facing. The depth of the cut is increased by turning an advancing screw.

Abstract: This invention uses a unique tubular cutting tool in a method for separating individual cables from the elastomeric body of a cable-type conveyor belt. The tool bores a cylindrical path through the elastomeric body coaxial with the individual longitudinal reinforcement cables. A transverse cut is then made across the belt width which just intersects the cylindrical paths which have been made around the cables. The elastomeric material can then be removed leaving only the cables exposed. The prepared belt end is then ready for application of a mechanical or vulcanized splice. The tubular cutting tool features both circular and axial cutting edges. The tool can be utilized in a hand drill to allow on-site splice preparation of the conveyor belt.

Abstract: A reamer for making a tapered hole is disclosed. The reamer comprises a cylindrical forward portion joined to the front end of a conical rear portion, the rear portion tapering outwardly from its front end. The forward and rear portions have co-incident longitudinal axes and at least three cutting flutes extending continously on the forward and rear portions and which are unequally spaced about the longitudinal axes. In one embodiment the flutes are either aligned with or helical about the longitudinal axes; and furthermore are misindexed about the axes and therefore are unequally spaced apart. In another embodiment the flutes have different helix angles about the longitudinal axis. In other embodiments the cylindrical forward portion is eliminated leaving only the conical rear portion making a reamer suitable for enlarging holes having existing tapers.

Abstract: An insert rotary cutter for processing a metal workpiece includes a cutter body of a generally circular cross-section having an axis of rotation therethrough. The cutter includes one or more cutter inserts releasably mounted on a periphery of the cutter body. The insert includes a generally quadrilateral plate defined by a front face, a rear face disposed generally parallel to the front face and four side faces. The insert has a pair of main cutting edges defined by the front face and one pair of the opposite side faces. The pair of opposite side faces serve as respective rake surfaces for the main cutting edges. Each of the rake surfaces is convexly curved in such a manner that the width of the insert between the rake surfaces is larger at a central portion of each main cutting edge than at opposite ends of the main cutting edge.

Abstract: A casing mill is set forth having a cylindrical body with one end adapted to be attached to a drill string and at the other end pilot vanes to guide the mill with respect to the casing. A plurality of blades project outwardly from the body to present a cutting edge for milling of the casing upon rotation of the mill. Polygonal tungsten carbide cutting elements are secured across a forward surface of each blade in a tesselating fashion, each element tilted in the direction of rotation of between 10-20 degrees. To mount the elements, the blade forward surface may include an inclined stairstep arrangement or inclined slots. Each element is brazed or bonded by a suitable organic adhesive to the forward surface.

Abstract: A new drill-type cranial perforator is disclosed of the type which comprises a front drill head assembly made up of a leading inner drill and a trailing outer drill, and a rear support and drive assembly adapted to enable both drills so long as the leading inner drill is encountering a resistive surface and to disable both drills when the leading inner drill stops encountering the resistive surface.

Abstract: An insert rotary cutter for processing a metal workpiece includes a cutter body having an axis of rotation therethrough. The cutter includes at least one cutter insert releasably mounted on an outer periphery of the body. The insert is of a generally polygonal shape having a curved front face. The front face has a pair of opposed marginal ridges serving as respective main cutting edges. The front face has marginal portions disposed adjacent and extending along the main cutting edges, and the marginal portions serve as respective rake surfaces for the main cutting edges. Each of the rake surface is convexly curved as viewed from a respective one of the main cutting edges and is concavely curved as viewed along a respective one of the main cutting edges.

Abstract: A self-drilling, self-tapping screw has a drill tip formed by a pair of conical segments. Each segment has a flat side and a rounded tip with one segment being longitudinally offset with respect to the other. The shorter, offset segment may have a greater included angle. At least a portion of the flat side of the second segment is coplanar with the flatside of the first segment. The screw preferably includes a quad-lead thread having two crests with a first diameter and two crests with a second larger diameter.

Abstract: A drill for drilling of work pieces, preferably of composite materials, comprising a cylindrical shank portion (11), a first cutting edge (13) in form of an arc of a circle arranged in the cutting end of the drill and a second cutting edge (16) perpendicularly connected thereto. The edges (13,16) are preceded in the rotational direction by a third cutting edge (14) which during the drilling cuts away the material radially inside a circular groove which is cut by the first and the second cutting edges (13,16).

Abstract: A reamer for making a tapered hole is disclosed. The reamer comprises a cylindrical forward portion joined to the front end of a conical rear portion, the rear portion tapering outwardly from its front end. The forward and rear portions have co-incident longitudinal axes and at least three cutting flutes extending continuously on the forward and rear portions and which are unequally spaced about the longitudinal axes. In one embodiment the flutes are either aligned with or helical about the longitudinal axes; and furthermore are misindexed about the axes and therefore are unequally spaced apart. In another embodiment the flutes have different helix angles about the longitudinal axis. In other embodiments the cylindrical forward portion is eliminated leaving only the conical rear portion making a reamer suitable for enlarging holes having existing tapers.

Abstract: A router tool and a cutting insert for transverse cutting of a work piece, preferably of fiber reinforced plastics. The router comprises a shank and a cylindrical router body having chip gullets and sites that have received cutting inserts. Each insert has a cutting edge which has a number of teeth extending in the rotational direction of the router. The inserts are staggered in the axial direction such that the router varying will present a right-handed cutting edge portion and a left-handed cutting edge portion whereby the work piece may be machined without producing defective burrs and fluffy fibers.

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: There is disclosed screw adapted to fasten two or more juxtaposed workpieces which comprises a threaded shank defining an axis and a major thread diameter. A drilling tip is provided which extends from the shank and includes a pair of cutting edges. Material removing extensions are formed continuously with the cutting edges and serve to extend the cutting edge in the radially outward direction at least as far as the radially outermost extent of the major thread diameter. The extensions are frangible and will fracture when a material of predetermined hardness is encountered. As such the fastener is adapted for drilling a first, enlarged bore in a first workpiece of relatively soft material, and a second smaller bore in a second workpiece of a harder material, such as metal, or the like.

Abstract: An insert cutter includes a body having at least one generally radially outwardly-opening recess disposed adjacent a forward end face thereof. A cutter insert is received in the recess. The insert is a polygonal shape having a front face, a rear face and side faces. Each corner portion where adjacent side faces intersect each other is removed to provide first and second corner faces. The insert has main cutting edges each defined by the front face and a respective one of the side faces, auxiliary cutting edges each defined by the front face and a respective one of the first corner faces, and corner cutting edges each defined by the front face and a respective one of the second corner faces. Each side face serves as a flank of a respective one of the main cutting edges with a positive clearance angle A. Each first corner face serves as a flank of a respective one of the auxiliary cutting edges with a positive clearance angle B.

Abstract: A drill is provided having opposed primary and secondary cutting edges extending perpendicular to the longitudinal axis of the drill. The primary cutting edge extends across the longitudinal axis of the drill to a terminus intermediate the longitudinal axis and the periphery of the drill. The secondary cutting edge extends inwardly from the periphery of the drill to a point intermediate the periphery and the longitudinal axis of the drill. The primary and secondary cutting edges are spaced from one another along the longitudinal axis so that the primary cutting edge leads the secondary cutting edge during a drilling operation. The primary cutting edge drills the inner part of the hole and the secondary cutting edge drills the outer part of the hole. The primary and secondary cutting edges are designed to generate substantially balanced forces about the longitudinal axis of the drill. Flutes extend from each cutting edge for efficient and reliable removal of chips.

Abstract: A cutting tool, for example a milling cutter, capable of omini-directional machining of a workpiece as disclosed. In a preferred form, the cutting tool is embodied as a ball nosed end mill having a cylindrical shank terminating in a spherically shaped cutting end with recesses shaped for receipt of at least two indexable cutting inserts, each insert mounted in lay-down fashion, and providing a portion of an effective overall arcuate cutting edge, the cutting zones of each insert overlapping each other. Each insert has the form of an equilateral polygon bounded by planar flanks, each flank intersecting a convex portion of a major face of an insert to form an arcuate cutting edge. The convex major face portion forms the clearance face and the planar flank portion the rake face for each associated arcuate cutting edge.