Abstract: A roll-forged drill bit 1 comprising a shank 3 for insertion in a chuck of a drill, the shank 3 including an helically twisted web 7 defining a cutting tip 9, the cutting tip 9 including a central chisel edge 11 and a cutting edge 15 defining the maximum diameter of the cutting tip 9, wherein the cutting tip 9 is formed after the shank 3 has been roll-forged and includes a pair of faces 13 defining the chisel edge 11 and a pair of upturned flats 17 defining the cutting edge 15. A roll-forged drill bit 1 according to the present invention provides a significant improvement in cutting speed over known prior art roll-forged drill bits.

Abstract: The present invention is directed to a semiconductor device having an ultra thin gate oxide and a method for making same. The method is comprised of implanting nitrogen into a region of a semiconducting substrate, and forming a gate dielectric above the region in the substrate. The method further comprises forming a gate conductor above the gate dielectric and forming at least one source/drain region. The present invention is also directed to a transistor having a gate dielectric positioned above a surface of a semiconducting substrate, the gate dielectric being comprised of a nitrogen bearing oxide having a nitrogen concentration ranging from approximately 4-8%. The transistor further comprises a gate conductor positioned above the gate dielectric and at least one source/drain region.

Abstract: A drilling head has a cylindrical body with a longitudinal axis, tapering towards a leading end thereof. The drilling head comprises at least two chip evacuation flutes and at least two lands therebetween. Each flute has a first side all facing in the direction of rotation of the drilling head and a second side wall diverging outwardly from the first side wall and merging therewith via a web-thinning recessed surface extending towards this leading end. Each land is bound by the first wall of one adjacent flute and the second wall of another adjacent flute and has a generally radially extending and axially inclined front flank face tapering towards the leading end. The front flank face of each land intersects the first wall of one flute at a primary cutting edge, the web-thinning recessed surface of this flute at a secondary cutting edge, and the front flank face of the other land at a chisel edge which is disposed at the leading end of the drilling head and which passes through the longitudinal axis thereof.

Abstract: The invention is a revolving pilot tool. The inventor's revolving pilot has a cylindrical shank which is attached to the tool usually in the center of the bottom of the tool. This shank has a threaded opening in its center. Over the shank is placed a cylindrical bearing. Over this bearing is placed another cylindrical piece that forms the outer surface of the pilot. To hold the bearing and the cylindrical piece upon the shank a screw and o-ring is usually used. This pilot is usually attached to the bottom of the tool to align the tool to an already drilled opening. However, it could be attached above a drill to align the tool to an opening being drilled. The pilot can also align the tool during line boring.

Abstract: An auger bit for forming bores having a circular cross section in a workpiece is disclosed. The bit has an elongate auger portion, a shank, a lead screw, a chisel blade, a spur blade, and a shearing blade. The elongate auger portion has an elongate shaft with a elongate helical land formed therein defining a flute between adjacent turns on the elongate helical land. The helical land has a lead edge and following portion. The shank is integrally connected to one end of the elongate auger portion and is adapted to engage a drill. The lead screw is integrally connected to the other end of the elongate auger portion and is for engaging the workpiece. The chisel blade extends outwardly from the leading edge of the elongate helical land and is for chipping material from the workpiece. The spur blade extends longitudinally from the elongate helical land in the direction of the lead screw. A cutting edge extends longitudinally from the following portion of the elongate helical land proximate to the leading edge.

Abstract: This invention is a countersink, counterbore or spotface, external pilot guide 98 which aligns a countersink cutter's edges 170, 171 and 172 into the center of a pre-drilled hole 15. The pilot guide indexes and attaches by lock down screw 165 to the countersink cutter 18 external body hole 160, three pilot legs 100 are recessed into the countersink cutter 18's flute pockets 150 and allows the cutting edges 170, 171 and 172 to extend through the pilot countersink cut-outs 140. Button nose 110 outside diameter comes in a range of sizes dependent on the pre-drilled hole 15 size (example: Pre-drilled hole size 0.375", button nose size 0.372") this allows clearance for friction expansion. All button nose 110 outside diameter's fit the same countersink cutter 18 and all have a hole in the center which allows the flare tube shaft 14 to move freely during the countersinking operation.

Abstract: A brad point drill bit having a boring tip defined by at least a pair of peripheral cutting members and a center blade disposed therebetween. The center blade is formed with a protruding central cutting edge for engaging a workpiece. The center blade also has two concave lateral cutting edges radially extending from the central cutting edge and rotationally offset therefrom. The peripheral cutting members comprise spurs having two cutting edges and pointed in a clockwise rotational direction of the drill bit.

Abstract: A cylindrical head boring tool (1), such as a Forstner drilling tool, with a main cutting edge (4) having a centering point (5). The main cutting edge extends diametrically across the entire circular cross-section of the boring head (3), the main cutting edge (4) having cut out surfaces (11), and chip channels (7) adjacent the main cutting edge (4). The chip channels (7) open through the outer periphery and extending obliquely through the boring head (3). Each end of the main cutting edge (4) is adjacent a preliminary cutting edge (8) coinciding with the circumference of the boring head (3) for guiding the boring tool (1). The preliminary cutting edge (8) reaches to the edge of the respective other chip channel (7) and forms the peripheral edge of an essentially cylindrically curved wall (6) of the boring head (3). The otherwise smooth wall (6) is interrupted by radial throats (13).

Abstract: A combination broacher-reamer includes a generally longitudinally symmetrical cutting tool which is provided with a plurality of longitudinal broaching cutting teeth as well as a plurality of axial reaming cutting teeth. According to a presently preferred embodiment, the broacher-reamer is generally cylindrical with a smooth blunt distal tip and a tapered distal cutting portion. The proximal end of the tool is provided with a handle and one or more witness marks are provided on the shank of the tool. If the handle is removable the shank may be coupled to a motor or impacting tool. An exemplary broacher-reamer according to the invention is approximately 6.78 inches long with an overall maximum diameter of approximately 0.843 inches. The proximal end of the tool has a diametrical throughbore which is dimensioned to receive the handle which is approximately 3.94 inches long. The cutting portion of the tool begins approximately 3.0 inches distal of the proximal end and terminates approximately 1.

Abstract: A rotary tool for drilling and chamfering, which takes place in one common advance, essentially comprises a base body, a drill clamped centered therein and a chamfering tool disposed on the end of the base body toward the drill tip and having a cutter body tip disposed next to the flank of the lateral free face of the drill. The chamfering tool can be radially adjusted in relation to the drill in a direction pointing at right angles in respect to the drill axis.

Abstract: A multistage bit is provided with a base part having a profile of stepped conical body with its tip cut off, and with a tip drill having a blade B of the smaller diameter than the blade B which is formed on the stage 2 at the foremost end of the base part A, the latter being provided freely detachably at the tip of the base part A.The stopper S for the above multistage bit comprises a ring shaped member having elasticity in the radial direction with its free diameter slightly smaller than the diameter of each stage of the multistage bit, a part of said ring shaped member being cut, and at least one cut end 18 thereof is bent to the center side of the ring so as to be stopped in the vertical groove 19 formed on the outer periphery of the multistage bit, and the height of the ring H is constituted to be equal to or slightly higher than the height of the stage 2.

Abstract: The present invention relates to a system for installing a length of cable through a wall. Thus, the system of the present invention can be used to route a television, telephone or computer cable through an existing wall. The system employs an electric drill and associated drill bit. Over the drill bit a routing tool is adapted to be fitted into and secured to the drill chuck of the drill. In use, both the drill bit and tool are secured to the drill. In the preferred embodiment, the drill bit is long enough to extend beyond the end of the tool. Next, the drill is used to cut a hole into a wall. Once through the wall the drill bit can be removed from the tool and the tool can be left within the wall. Any type of cable can now be positioned through the tool within the wall. Lastly, the routing tool can be removed from the other side of the wall and used again elsewhere.

Abstract: It is the object of the present invention to drill a hole and, at the same time, transmitting an application force exactly to an undercutter for forming an undercut space in the cylindrical wall of the hole at a position near the hole bottom. An apparatus according to the present invention includes a rear circular member 1, a sleeve 10 supported in telescopic engagement with the rear member 1, an undercutter 5, and a front annular member 15 linking and movable with the undercutter 5. The sleeve 10 has an inner flange 13 forward from the rear member 1. An application force transmission mechanism 18 comprises a cam 20 supported by the rear member 1. The cam 20 has a pair of steps 21 and 22. The transmission mechanism 18 also comprises a first impact transmission rod 23 extending between the cam step 21 and sleeve flange 13, and a second impact transmission rod 24 extending between the step 22 and front member 15.

Abstract: A bone contouring tool for removing bony tissue surrounding an implanted dental implant and having an elongated shank with a blade and a pilot pin disposed at one end. The pilot pin extends downwardly from the blade and provides guidance during removal of the bony tissue.

Abstract: A percussive blow assisted rotary drill includes an axially extending shank (1) with a leading end face (3) and an axially extending outside surface (2) containing a helically extending drilled material removal groove (4, 5). At least one hard metal cutting plate (6) extends across a diameter of the shank and has a base part fixed in a continuous groove (9) in the leading end face (3) of the shank (1). The base part (10) is reinforced by an outwardly extending projection (12) in at least one of its side surfaces extending across the shank diameter. Preferably, the projections forms a part of a circle and are centered between the opposite ends of the cutting plate. The continuous groove (9) has a recess in at least one of its side surfaces shaped to coincide with the shape of the outward projection (12) on the cutting plate. Accordingly, the base part (10) is secured in a positively locked manner and preferably is centered in the leading end face of the shank.

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 boring apparatus which includes a rotatable cutting head used to cut a hole in a workpiece. The cutting head is mounted on an axially movable support, and is rotatable about and reciprocally movable along the axis between a forward cutting position, to engage and cut the workpiece, and a rearward position spaced from the workpiece. Cutting is performed by a cutting blade which is spaced radially from the axis, and which is movable relative to the rest of the cutting head by a blade advance mechanism. During cutting operation, the blade advance mechanisms move cutting blade both forwardly and radially inwardly through the workpiece wall, in the same direction at which the blade is inclined. The hole is thus formed by lowering the cutting head and then rotating the cutting blade as the blade advance mechanism moves the blade at an angle through the workpiece.

Abstract: A device for performing a plurality of operations on a workpiece has a combination tool holder and a rotatable spindle for retaining the tool holder. The combination tool holder has a central opening at its forward end for receiving a drill bit and a pair of forwardly extending bosses onto which a pair of cutting tools are received. A slot is provided in the tool holder dividing it into a pair of gripping elements receiving the drill bit, the gripping elements being forced together onto the drill bit when the tool holder is mounted in the spindle.

Abstract: A unitary instrument for providing a step-down screw hole in a pedicle is provided. The tool includes an end member for rotatable connection with a power source, the probe for providing a pilot hole in the pedicle and a side-cutting reamer member for providing an anchor hole for a pedicle screw positioned about the pilot hole. The arrangement is such that the instrument is self-centering in part due to the presence of the probe in the pilot hole.

Abstract: A tap is disclosed wherein a cutting zone has bottom teeth with axial and radial form relief. A pilot means below the cutting zone has at least one zone of axial and radial form relief oriented opposite from the teeth form relief. A flute extends through both pilot means and cutting zone.

Abstract: A cutter body for counter sink drilling fiber reinforced plastic materials, such cutter body having a pilot portion at a distal end of the cutter body and a countersinking section formed adjacent to the pilot portion in a region on the base end side of the cutter body. The countersinking section comprises three unit machining sections disposed with equal angular intervals in the circumferential direction of the cutter body. Each unit machining section comprises an abrasive layer formed by electrodepositing diamond abrasive grains on a conical surface in turn provided on the cutter body with a chip discharge groove and a finishing edge overhanging from the abrasive layer by an amount t and disposed in order successively rearward in the direction of rotation of a drill or cutter. The finishing edge is formed on a hard sinter, which contains diamond grains as a main ingredient, on a laminar sinter.

Abstract: Apparatus for cutting a smooth concentric hole in a metal workpiece. The apparatus fits in a standard industrial drill chuck and has a pilot drill and tap at one end which drills and taps a pilot hole seating a mandrel on the metal workpiece. When the mandrel is seated, a cam plate and spring arrangement automatically advances the cutting teeth and provides the proper pressure on the cuttering teeth to cut the hole. The cutting teeth have a special anti-breakthrough portion which provides controlled drilling of a smooth hole. A clutch is provided which controls the torque delivered to the apparatus and allows the cam plate to function properly. The device may be adapted easily to accommodate various hole sizes by changing its faceplate.

Abstract: Flat drill bit for drilling holes in wood, comprising a plate (12) with two longitudinal sides (16,17), two main radial edges (14,15) and a pilot point with two converging pilot edges (18,19), where main radial edges, pilot edges and short lateral edges (24,26) being short portions of the longitudinal sides all have positive rake angle, produced by grooves parallel to the edges facing forwards during rotation. For larger diameters the pilot point has two converging pilot edges and two parallel sides (27,28).

Abstract: The present invention comprises a wood bit for use in wood working applications. The blade of the bit is generally spade shaped having cutting spurs on each corner of the blade, a central point projecting from the leading end of the blade, and hooked cutting edges.A progressive transfer die is used to bend the leading end of the blade and forge a continuous hook angle extending along the side cutting spur, the lateral shoulder, and the central point of the blade. The forging of a hook extending from each side of the blade converging at a central point provides a hook along the leading end of the blade projecting outwardly (in the direction of rotation) past the plane of the blade face. The leading end of the hook is beveled forming a continuous cutting edge extending along the hook from the outer side wall of the blade through the outside cutting spurs, along the lateral shoulders, and along each side of the central point.

Abstract: A drilling tool has a drilling crown (12) removably arranged on a shank (10) at its front face, provided with two complementary regions that are mutually separated by chip channels (20) and that have partially circumferential surfaces (48). The drilling tool also has at least two cutting plates (14, 14', 16, 16') secured to the regions of the drilling crown and spaced apart by an angle of 180.degree., as well as a centering drill (26) centrally arranged in the drilling crown in the axial direction that projects over the front face of the latter. The cutting edge (18) of the outermost cutting plate (14) in the radial direction radially projects over the circumferential surfaces (48) of the drilling crown (18), whereas the working area of the innermost cutting plate radially approaches or overlaps the working area of the centering drill (26).

Abstract: A drilling tool and, in particular, a rock drill for the creation of breaches in concrete or masonry for the use of drill hammers is proposed, which is configured as a cross drill bit having four cutting fins. In order to optimize drilling capacity, the drilling tool is provided with a cross drilling head which merges in one piece into a conveyor spiral matched to the drill head. A purpose-specific cutting element facing serves to optimize the drilling capacity.

Abstract: A bit usable in combination with a rotatory driver, such as a drill, for extracting a remnant of a cut-off pipe from a pipe socket. The bit comprises a forward portion which is a pilot to keep the bit centered in the remnant and thereby centered in the pipe socket, a forward-facing ring cutter whose inner and outer diameters generally match the inner and outer diameters of the pipe remnant being extracted, said ring cutter being operable to cut and/or scrape the remnant edgewise from the socket, and a forward facing ring scraper operable to stop the bit from excessive penetration into the pipe socket and operable to scrape bonding material remnants from the end face of the pipe coupling.

Abstract: A pilot drill bit includes a shank, with an abutment flange mounted fixedly to the shank, and coaxially aligned relative to the shank and the abutment flange are a plurality of drill sections of decreasing diameter terminating in a tip, with the sections arranged and sized for drill taps.

Abstract: A cylindrical bit including a drill head with a centering tip, two circumferential cutters, two main cutting edges extending approximately radialy, and two chip channels associated with main cutting edges. The chip channels are open toward a circumferential surface and toward a rear of the cylindrical bit. To improve chip removal, each chip channel bottom surface is rounded in a curved fashion and blends continuously with the respective chip surfaces of the corresponding main cutting edges and with chip channel side walls opposite the respective chip surfaces.

Abstract: A self-centering twist drill bit 20 is formed with a "fishtail" cutting section 32 having major cutting lips 72 and 74 on a working end 26 thereof at a point angle of 190.degree.. Tip relief surfaces 76 and 78 trail cutting lips 72 and 74. A pilot tip 38 on the working end 26 extends axially from the "fishtail" cutting section 32 and is formed with a split point having leading cutting edges 40 and 42 and minor cutting lips 46 and 48. Outer surfaces 58 and 60 of pilot tip 38 are each formed with a radial relief and a back taper and joins with cutting section 32 along fillets 92 and 100 which are also radially relieved.

Abstract: The present invention comprises a wood bit for use in wood working applications. The blade of the bit is generally spade shaped having cutting spurs on each corner of the blade, a central point projecting from the leading end of the blade, and hooked cutting edges.A progressive transfer die is used to bend the leading end of the blade and forge a continuous hook angle extending along the side cutting spur, the lateral shoulder, and the central point of the blade. The forging of a hook extending from each side of the blade converging at a central point provides a hook along the leading end of the blade projecting outwardly (in the direction of rotation) pass the plane of the blade face. The leading end of the hook is beveled forming a continuous cutting edge extending along the hook from the outer side wall of the blade through the outside cutting spurs, along the lateral shoulders, and along each side of the central point.

Abstract: Drilling/chamfering tool, comprising a tool holder (3) which holds at its front end a chamfering head (2) and a commercially available drill (1) with cylinder shaft, and appropriate adjusting and cutting elements. It is essential in the drilling/chamfering tool that the cylinder shaft (D) of the drill (1) is greater than or equal to the drill diameter (g) and has at least one clamping surface (g). The chamfering head (2) is rotatable 360.degree. about the tool axis (a), while two chamfer cutting blades (4) are arranged diagonally opposite each other in the chamfering head (2) and are clamped adjustably against the diameter (d.sub.1) of the spiral back (j) essentially at chamfer angle (.lambda.). The particular advantage is obtained that optimum cooling and no accumulation of chips is achieved and a modular tool system with uncomplicated availability and inexpensive procurement and storage is provided.

Abstract: The milling tool, in one form, has a shank having a shank rotation axis, a first cutting-edge carrier having at least one cutting edge and at least two arched areas and a second cutting-edge carrier having at least one cutting edge and at least two arched areas. The arched areas are shaped and positioned to form a tubular socket in which the shank is attached with both cutting-edge carriers radially projecting in a lobe-like manner from the shank and being rotatable about the shank rotation axis. The at least two arched areas of both cutting-edge carriers are spaced from each other axially, have surfaces normal to the shank rotation axis, arch in the same direction and are displaced from and parallel to the shank rotation axis so that the first and second cutting-edge carriers mutually overlap to form the tubular socket for the shank so that, when the shank is attached in the tubular socket, the cutting-edge carriers are locked against each other.

Abstract: A drill bit includes an elongated shaft with a threaded male end and a cutting head with an axial through-bore having female threads to receive the male end of said shaft in threaded engagement, and there is a bearing surface area between the shaft and the cutting head above the threaded portion which provides for proper alignment and reduced stresses.

Abstract: A adjustable chamfering reamer used in automated threading machines for reaming the ends of pipe or conduit. The adjustable chamfering reamer has an inner reamer insert adjustably installed within a generally cylindrical outer sleeve. The front of the outer sleeve has circumferentially spaced forwardly extending projections with a flat inwardly and rearwardly angled reaming surface and a trip shoulder at the bottom thereof. The inner reamer insert has a trunched conical forward end defined by a plurality of circumferentially spaced longitudinal wings extending rearwardly and outwardly from the forward end and the exterior of the wings are curved reaming surfaces. When assembled, the wings are positioned between the projections of the outer sleeve in alternating relation. When viewed from the side, the overlapped reaming surfaces and shoulders form a plurality of rearwardly extending flat-bottom V-shaped grooves.

Abstract: In a preferred embodiment, a cutting tool mountable in a rotatable chuck and having a cylindrical cutting member with a cutting surface orthogonal to the axis of the cutting member. The cutting surface includes at least 8 cutting flutes defined therein. The cutting flutes are rounded at the outer periphery of the cutting surface so as to permit chips to clear the cutting surface as the tool is used.

Abstract: A drill head assembly for a cranial perforator, which assembly is similar to the drill head assembly disclosed in U.S. Pat. No. 4,884,571, except that the configuration of the axially-projecting sections of the front end surfaces of the inner drill are modified to cause the inner drill to stop rotating more quickly upon penetration of the inner drill through a skull.

Abstract: For cutting a facing such a countersink or a spot facing a rotary cutter is provided with a body having a central aperture arranged to receive a drill or other guide and at least one cutting insert carried by the body rotates with the drill or guide to cut the facing. The insert has a forward cutting edge which projects radially inwardly to form a step projecting inwards relative to the main body of the insert behind the cutting edge region. The drill has a radially recessed portion, such as the radial relief or the flute of the drill, to accommodate said step of the cutting edge region. Such a cutter can be designed to operate at high metal removal rates and can be used with standard forms of drill and reamer.

Abstract: An improved drill bit for wood boring or boring in other relatively soft material, having a generally cylindrical shaft (20), with a flattened blade portion at one end (24). The blade portion (24) is broad and flat with essentially parallel side surfaces (41, 42) and having negatively beveled edges along the length of such side surfaces, such side surfaces giving way to a modified end edge. The modified end edge includes a center point, with a length of one half to several times the thickness of the blade, and said point (34) is centered on the end edge and is made with a triangular shape with a vee groove from the center of the base to the middle of the vertex. (35). Outer spurs of rectangular cross section (29 and 30) with a concave tip and a negative bevel away from the leading edge are located on the lateral extremities of the end edge.

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: The cutting edges (16) of a 3-toothed countersink bit (10) lead slightly in the direction of rotation by an amount (t). The rear face (38) of the head (40) of a detachable pilot (30) is concave so as to fit snugly over the forward end of the bit (10). Lubricant is supplied via a bore (28), flats (44) on the pilot shank (32), a chamber (42) at the mesal end of the shank (32) and notches (46) in the tip of the bit to the spaces between the teeth (14).

Abstract: A plastic closet flange reboring tool having an elongated arbor, a cutting member and two exchangeable non-circular guide members. The arbor having a first end structured of a D-shaped threaded extension, and a second end structured for releasable connection to a rotatable tool chuck. The cutting member is generally concavo-convex in structure with the guide member being generally rectangular and flat with rounded terminal ends. Both the cutting member and guide member have central D-shaped apertures sized for receiving the D-shaped threaded extension of the arbor. Both the cutting member and guide member are releasably adjustably retained on the D-shaped threaded extension of the arbor with threaded nuts.

Abstract: A body reaming tool for body work which can be used with a conventional drill to remove spot welds during automotive body repairs. A rigid shank coaxial with the longitudinal axis of the tool is fitted within the conventional chuck of a suitable electric hand drill. This increased diameter section is integral with the shank, and it includes an internal bore which coaxially receives twist drill bit used as a pilot. A conventional machine screw is employed in the counterbore section to lock the drill bit in place. The counterbore terminates in a plurality of fluted cutting teeth of a special configuration for quickly removing the metal, while preventing the metal from burring or otherwise interfering with subsequent part separation. Each of the cutting teeth terminate in a leading point which initially engages metal and the body part to be removed. A plurality of spiraling flutes are defined between the cutting teeth.

Abstract: A self-centering twist drill bit 20 is formed with a "fishtail" cutting section 32 having major cutting lips 72 and 74 on a working end 26 thereof at a point angle of 190.degree.. Tip relief surfaces 76 and 78 trail cutting lips 72 and 74. A pilot tip 38 on the working end 26 extends axially from the "fishtail" cutting section 32 and is formed with a split point having leading cutting edges 40 and 42 and minor cutting lips 46 and 48. Outer surfaces 58 and 60 of pilot tip 38 are each formed with a radial relief and a back taper and joins with cutting section 32 along fillets 92 and 100 which are also radially relieved.

Abstract: An improved drill bit for wood boring or boring in other relatively soft material, having a generally cylindrical shaft (20), with a flattened blade portion at one end (24). The blade portion (24) is broad and flat with essentially parallel side surfaces (41,42) and having negatively beveled edges along the length of such side surfaces, such side surfaces giving way to a modified end edge. The modified end edge includes a center spur that is of rectangular cross section, with a length of one half to several times the thickness of the blade, and said spur (34) is centered on the end edge and is made with a concave tip (35). The edges of the center spur are parallel from vertex (36) to base. Outer spurs of rectangular cross section (29 and 30) with a negative bevel away from the leading edge are located on the lateral extremities of the end edge.

Abstract: A valve seat refitting apparatus. A cylindrical main body portion has a longitudinal bore which receives a centering guide. Longitudinal slots around the outer periphery of the main body portion receive cutting blades rigidly attached to cutting blade support. Radial and longitudinal positioning screws serve to position the supports and cutting blades to refit a variety of valve seats. Set screws lock the blade supports in the desired position. A bushing removably attached to the centering guide also allows the centering guide to be adapted to fit different size valve seats.

Abstract: Tooling to form a countersink and counterbore in a workpiece includes:(a) a first part defining an axis and that extends axially forwardly in a bore hole in the workpiece,(b) a rotatable carrier connected with that first part,(c) and a cutter blade on the carrier, the blade projecting radially relative to the first part forming at least one cutting edge spaced outwardly of a cylinder defined by that first part, the cutting edge shaped to form the countersink and counterbore at one end of the bore hole.

Abstract: Tooling to form a countersink and counterbore in a workpiece includes:(a) a first part defining an axis and that extends axially forwardly in a bore hole in the workpiece,(b) a rotatable carrier connected with that first part,(c) and a cutter blade on the carrier, the blade projecting radially relative to the first part forming at least one cutting edge spaced outwardly of a cylinder defined by that first part, the cutting edge shaped to form the countersink and counterbore at one end of the bore hole.

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.The leading inner drill has at least one drilling flute with a forward cutting edge including a reentrant cutting segment axially rearward from the outer end of the forward cutting edge and extending inwardly towards the longitudinal axis of the perforator.