Abstract: A self-aligning tapping tool comprises an elongate handle having a longitudinal counterbore through a first end. A tap is received in the counterbore. A collar is operatively secured to the tap. The collar is slightly smaller than the counterbore to enable slidable movement and to prevent rotation of the tap relative to the handle. A retainer is secured to the handled at the first end to retain the collar in the counterbore and has a center opening receiving the tap. A biasing spring in the counterbore biases the tap and the collar outwardly to extend the tap when the handle is turned to thread a hole in a work piece.

Abstract: A thread cutting tool for cutting female threads includes a shaft and a cutting section composed of several groups of cutting teeth alternating with chip grooves. At least some of the teeth, preferably teeth disposed in a front region of the tool, have undercuts in their flanks which define radial steps, each step spaced circumferentially from a cutting edge of the respective tooth in order to form a space which facilitates the escape of cuttings.

Abstract: A method of producing a nut having a drive area and a clamping area, and a screw tap for performing the method. A bore hole running through the clamping and drive areas is produced in a cylindrical manner. The screw tap is screwed into the cylindrical bore until a predetermined position is reached. The screw tap is successively provided, when seen in an axial direction from the front side thereof, with a centering/cutting section, an adjoining cutting section which is used to produce a conical internal screw thread section in the clamping area, and a cutting section which is used to produce a cylindrical internal screw thread section in the drive area.

Abstract: The concept of my idea is a tool used in conjunction with a ratchet wrench that would re-thread a hole into which a spark plug was inserted or other holes with in which the threads are cross-threaded. It can be used in engine cylinder heads on both styles of engines, works well with over head cam engines. Produced from tool-grade steel, measuring 5 inches long and vary in diameter (½ and ⅜ inch.) ⅜-inch diameter found at the top of this tool would allow for the attachment of a ⅜-inch drive shaft of a ratchet wrench. The bottom of the shaft would feature threads that allow internal threads to align correctly. A ratchet wrench would be cranked to create the turning motion needed to cut the threads. This tool provides convenience, durability, and efficiency. The professional auto mechanics and the do-it-yourselfer can use it.

Abstract: A thread forming tap comprising a shank section, a body section extending longitudinally from the shank section, a helical thread formed on the body section having radially converging flank portions and an undercut ramp formed in at least one of said flank portions at a predetermined angle.

Abstract: A thread forming tap which is capable of reducing tapping torque as well as improving durability by avoiding an increase of an apparent area of margins of external thread that causes interference with a grinding stone. The thread forming tap has an external thread in a screw shape with alternately linked margins and reliefs for forming an internal thread by plastic deformation upon having the margins of the external thread bite into a surface of a prepared hole of a workpiece. A helix of the margins of the external thread is in a direction opposite to a direction of a helix of the external thread relative to an axis of the tap.

Abstract: A cutting tip having a three-layer laminated structure is provided. The tip is made from a disc-shaped three-layer laminate wherein a second layer consisting of a hard sintered compact of CBN or diamond is sandwiched by a first layer and a third layer consisting of a tool material such as cemented carbide. Prismatic blanks of rectangular cross-section are cut out by cutting the three-layer laminate in strips. Semi-completed tips of a desired shape are obtained by cutting up the prismatic blanks. Desired cutting edges are formed on the semi-completed tips to produce completed tips. Because prismatic blanks are obtained from a three-layer laminate and semi-completed tips are cut out from the prismatic blanks like this, the semi-completed tips can be obtained in large numbers, yield is high, and the manufacturing cost of the tip can be reduced.

Abstract: A tapping tool for repairing damaged threads on PVC pipe and PVC pipe fittings (e.g. T-connectors, elbows, etc.) includes an elongate shaft with a handle member fixed to a proximal end and a head fixed to an opposite distal end. A threaded tap formed of hardened steel is positioned and disposed on the head for forced, threaded engagement with the threads of the PVC pipe or fitting. Manual rotation of the handle serves to advance and withdraw the head along the threads of the PVC pipe or fitting as the tap cuts and reshapes damaged threads, thereby restoring the threads of the PVC pipe or fitting to a uniform, functional condition.

Abstract: Disclosed is a tap driver for rigid tapping, which includes predetermined tension and compression factors to self-synchronize the tap driver. In the preferred embodiment, the tap driver includes helical coils imparted in the tap driver body which allow the attachment body to synchronize axially in response to a force of a predetermined magnitude imparted on the tap. An additional embodiment of this invention provides such a tap driver body wherein the body allows for lateral flexure and movement to compensate for feed error and location error.

Abstract: A tandem tap for cutting screw threads into a bore comprises straight flutes with a spiral point along the front section for pushing the chips generated thereby forward and spiral flutes along the rear section for removing the chips generated thereby rearward in an opposite direction. The tap prevents build up of chips in the transition area between front and rear cutting sections of the tap.

Abstract: An aftermarket retrofit kit is used to prepare control arm bosses of automotive suspension systems to receive new, replacement ball joints. The kit includes a special cutting tool for forming obtuse threads in the apertures of aluminum suspension system mounting bosses for replacement of spent or used steel ball joints originally pressed-fit into forged aluminum control and steering arms. Since unthreaded apertures of bosses of control and steering arm joints in which the original pressed fitted equipment ball joints may be threaded to receive the new joints, avoidance of having to replace expensive original control and steering arms is made possible by the reuse of such arm parts normally discarded. A separate alignment block is included to assure accurate piloting of the cutting tool. Threading of the control arm bosses can be done on or off of the vehicle, and separate kits are provided for upper and lower control arms.

Abstract: The invention provides a chasing tool for repairing damaged internal threads, including a body provided with a bore; a handle retained in the bore with one degree of freedom in rotation, the handle being provided over at least part of its length with an internal thread; a cylindrical component having an external thread matching the internal thread of the handle; a tubular member fixedly attached to the body perpendicular to the axis of rotation of the handle and opening into the bore of the body and a lever tiltable about a pivot providing the lever with one degree of freedom in rotation, the cylindrical component being articulated to the lever and a cutter articulated to the other end of the lever, the cutter projecting from the tubular member.

Abstract: A tandem tap for cutting screw threads into a bore comprises straight flutes with a spiral point along the front section for pushing the chips generated thereby forward and spiral flutes along the rear section for removing the chips generated thereby rearward in an opposite direction. The tap prevents build up of chips in the transition area between front and rear cutting sections of the tap.

Abstract: A thread rolling tap including a stem portion, and a thread forming portion having a body with a plurality of thread turns formed on the body and including a front entrance region and a guide region, with the thread turns having each, in the front region in vicinity of the body, inclined pressure flanks forming side surfaces of an acute angle and connected by an outer, arranged radially outwardly with respect to the body, pressure surface formed as a flattening having opposite rounded edges extending along a circumference of a respective thread turn.

Abstract: A cutting tap comprises a threaded portion including a lead whose thread diameter gradually decreases toward a front end of the lead, a complete thread portion continued from the lead, and four flutes arranged at equal intervals in a circumferential direction. In the cutting tap, a first cutting edge portion for processing a prepared hole is formed at a front end surface of the lead, and a second cutting edge portion for finishing a minor diameter of an internal thread is formed in a part of an outer periphery of the complete thread portion, the second cutting edge portion being one or more pitches long. The cutting tap can perform processing of a prepared hole, tapping, and finishing of a minor diameter by a single step, and can also perform tapping even if a prepared hole for an internal thread is a blind hole or the like and does not have enough space.

Abstract: It is an object of the invention to provide a thread-forming tap to which a chamfer can easily be mounted, and a general threading method. The thread forming tap of the invention has a threaded portion comprising a tapered chamfer and a parallel threaded portion which is formed continuously with the chamfer. A depth of root of the chamfer is set equal to that of a root of the parallel threaded portion constantly.

Abstract: The invention involves a threading tool (20) for defining an internal thread within walls (62) of a cavity (64) within a workpiece having a floor (66) around an axially disposed protuberance (68) with a top (70) extending from the floor (66). The threading tool (20) includes a first end portion (22) for gripping and a second end portion (24) for threading. Threads (30) are formed on the second end portion (24). An opening (40) is axially disposed at the second end portion (24) and extends inward to form a recess (42) and recess bottom (44) over which the threads (30) extend a distance (A), allowing internal threads to be formed along the walls (62) past the top (70) of the protuberance (68).

Abstract: Apparatus for tapping or threading holes in material reduces stresses and the danger of breakage of the tap by rotatably driving the tap at locations on the tap that change as the tap enters the workpiece. The driving element engages the tap at a point close to the surface of the workpiece. As the tap advances into the workpiece, the driving element remains close to the workpiece surface, engaging the tap at sites progressively advancing toward the end of the tap. Special taps are provided, one of which is double ended. This may be turned end for end to double the useful cutting life. This embodiment is driven by its flutes. Another tap is driven by a non-circular shaft extending from the threaded portion of the tap. The taps may be removed from the workpiece by passing through the threaded hole, thereby eliminating the need to unscrew the tap through the already tapped hole.

Abstract: A cold forming tap with an internal finish cutting edge includes an external thread portion having radially outwardly protruding portions and relief portions which are alternately located in a helical direction in which an external thread extends. The protruding portions are forced into a surface of a prepared hole which has been previously formed through a workpiece, for thereby forming an internal thread on the surface. The improvement comprises: at least one of the protruding portions having a root diameter larger than that of the other of the protruding portions, the at least one of the protruding portions being removed down to a root of the external thread, and a flute being formed in a portion corresponding to the root of the at least one of the protruding portions, so as to provide the cutting edge in the portion corresponding to the root.

Abstract: A high durability taper tap for pipe threads which can cut threads in a pipe made of hard materials having hardness of approximately 50 HRC. The sum &Sgr;&ggr; of the width angle of cutters is large, approximately 130°, thereby achieving high strength and rigidity are achieved. Since rake angle of the cutting edge &agr; is approximately −20°, cutter angle &bgr; defined by the rake face and the peripheral relief becomes more than 90° so that the strength and rigidity of a cutting edge are enhanced. In addition, since a taper of the bottom of flutes is in a ratio of 1/16, approximately equal to that of the thread portion, the rake angle &agr; of all of the cutting edges 6 is uniform so that all of the cutting edges can equally cut the threads. Further, the diameter Df of the bottom of the flutes of the top end portion is approximately 60% of the smaller end of the thread portion, which is larger than that of the common tapping tool.

Abstract: An electrical fitting tap for retapping the hollow interior edge of a junction box or the like comprising a unit having two milled taps that are opposed and concentrically aligned at a joint provided with four opposing holes within which a cheater bar can be inserted. The center of each of the taps is open so that wires within the electrical fitting box can be threaded through the tool and positioned out of the way when the retapping is accomplished.

Abstract: The invention concerns a process for the manufacture of a cutting insert (1) for thread cutting, with several cutting teeth (2-6) simultaneously engaged in incrementally cutting the thread profile. The blank is manufactured by pressing and sintering so that the relief angles of the flanks of the side cutting edges (9,10) of the individual teeth (2-6) are at least 3.degree. and the profile depth of the final cutting tooth (6) which makes the finishing cut on the thread fits within the required final measurement tolerances, while the thickness of the cutting insert (1) and the tooth width (b) of the cutting teeth (2, 3, 4, 5, 6) are oversized. Subsequently, the blank is mechanically processed on the back face (7) and/or the front face (8) until the tooth width (b) of the cutting teeth (2, 3, 4, 5, 6) and the thickness (d) of the cutting insert (1) fit within the required final measurement tolerances.

Abstract: Solid tungsten carbide is the popular material for these combinations tools. High resultant side forces on the tool during the thread milling phase are caused by relatively high circumferential engagement of the tool and a very low feed per tooth (chip thickness). A combined hole making, threading and chamfering tool with staggered thread cutting teeth doubles chip thickness and reduces side forces (resulting in less engagement), consequently allowing the feed rate to be increased while reducing thread milling time. In addition, this arrangement also reduces tool chatter, thus providing a smoother surface finish in the thread. In one form, the cutting teeth are formed on one or more removable inserts, facilitating replacement or substitution thereof.

Abstract: A thread-producing tool for producing an internal thread includes a body forming a rear shank portion and a front cutting portion. Provided in the body is a lubricant storage chamber for storing liquid lubricant which is driven toward the cutting portion through discharge passages under the action of centrifugal force during a thread-cutting operation.

Abstract: Apparatus for forming threads of varying pitch on a work piece, by first producing a partial thread and groove whose pitch does not vary in accordance with a pattern of pitch variation desired for the final product, and then reshaping the partial thread and groove to a final form whose pitch does vary in accordance with the desired pattern. The two steps may be performed by a single tool having a series of thread cutting projections which form the partial thread, and having one or two additional projections which then reshape the partial thread to its final form.

Abstract: A thread-cutting chuck for CNC machine technology of rigid tapping, with a clamping means held in a chuck shaft, particularly a collet chuck, for the tap, an accommodating part, which is held in the chuck shaft without clearance in the direction of rotation and, in the axial direction in the tension and compression directions, has a slight axial clearance cushioned by elastomeric connections disposed between the clamping means and the shaft of the chuck.

Abstract: A guard apparatus for a rotational tool prevents direct contact of the cutting regions by an operator of the tool. The rotational cutting tool to which this invention is particularly applicable is the type having at least a shank portion and a toothed region, with the shank portion attachable to a holding attachment device to hold the tool, particularly during operation. The guard apparatus comprises a compressible guard housing for defining a guard circumferential area following a circular path parallel to but greater than a cutting circumferential area defined by the toothed region of the rotational cutting tool; and a first securement device having a first periphery at a first end for abutting the holding attachment device and a flared and tapered periphery at a second end for associating with the compressible guard housing.

Abstract: A lordotic implant has a frusto-conical shape with external threads. Prior to placement of the implant, vertebrae are distracted in a manner to provide a desired lordosis between the vertebrae. The pre-distracted vertebrae are then tapped to provide a tapped bore having a geometry matching the conical geometry of the implant. The threaded implant is then placed within the pre-tapped conical bore.

Abstract: A lordotic implant has a frusto-conical shape with external threads. Prior to placement of the implant, vertebrae are distracted in a manner to provide a desired lordosis between the vertebrae. The pre-distracted vertebrae are then tapped to provide a tapped bore having a geometry matching the conical geometry of the implant. The threaded implant is then placed within the pre-tapped conical bore.

Abstract: A tool for repairing damaged threads within a bore. A generally cylindrically shaped tool body includes a threaded section at its bottom end, and an axial bore extending from a point adjacent the bottom end of the tool body to an upper terminal point in a higher portion of the tool body. The bore is closed off at its bottom end by a disk-shaped wall. A particulate waste entry aperture in the wall surrounding the axial bore is located adjacent the bottom end of the tool body, and an exit aperture is located higher in the tool body. Drive-receiving means is located at the upper end of the tool body. A housing, in which the tool body is rotatably secured with an airtight seal, encloses the portion of the tool body in which the exit aperture is located. The housing provides a space that completely encircles the tool body, and is in communication with the exit aperture at all times. The housing has an outlet opening that can be operatively connected with a conventional suction source and waste disposal system.

Abstract: A tap having a reamer edge which is provided at a chamfer part, so that when the thread forming tap is pulled out after the internal thread is formed, a seam portion present at the crest of the internal thread is cut off, whereby even in a blind hole, formation of internal thread and cutting of the seam portion are performed in a single process, and formation of an internal thread and processing of an inside diameter portion are achieved in a single process to obtain concentricity in line with each other. Further, even if there is a deviation in diameter of the hole before threading, the inside of the internal thread is processed to a constant value.

Abstract: Axial loads encountered during thread cutting are reduced by controlling interactions between rotation speed, axial feeding speed, feeding (threading) pitch, and feeding position. A counterload is generated by changing a feeding pitch to a corrected feeding pitch, which changes the rotation speed, while keeping the feeding speed constant; by changing the feeding speed, while compensating the rotation speed (which is derived from the feeding speed) to remain constant; by changing the rotation speed, while compensating the rotation speed deviation feedback (to allow the deviation correction to follow the rotation speed change), while keeping the feeding speed constant; by generating a function according to empirical results that controls the feeding pitch, and therefore the rotation speed, while keeping the feeding speed constant; and by combinations of these methods.

Abstract: A drilling and thread-milling tool for generating an internal thread in a workpiece, including a proximal shank portion attachable to a driving device for rotating the tool about a rotation axis thereof, and a distal cutting portion rotated with the shank portion about the rotation axis for generating the internal thread while the distal cutting portion is moved relative to the workpiece. The cutting portion has at least one thread-milling tooth on an outer circumferential surface thereof, each tooth having a configuration similar to that of the internal thread, and a height substantially equal to a depth of the internal thread. The cutting portion further has at least one end-cutting edge on a distal end face thereof so as to extend in a radial direction thereof, each end-cutting edge having a maximum diameter which is larger and smaller than a minor diameter and a major diameter of the thread-milling tooth.

Abstract: A thread tapping cutting tool includes a working part with a chamfer portion, control portion, and at least two thread cutting wings (separated by flutes) formed therein. The chamfer portion is at least one half of the length of the working part. Each of the two or more thread cutting wings has a width of not more than 0.2 times a tap drill outer diameter of the working part, and not less than 0.02 times the tap drill outer diameter. The chamfer portion has plane surface lands on the cutting wings at the outer edge, and a relief angle of the plane surface lands is greater than 5 degrees. The core diameter of the cutting wings is defined by the depth of the flutes, and is not more than 0.35 times the tap drill outer diameter.

Abstract: A rethreader tool for use in a internally threaded hole of which the internal thread pattern is in need of repair. The assembly providing a expandable, collapsible and reusable device for achieving the purposes of the internal thread repair. In the collapsed state the rethreader finger section of the base can be inserted into the damaged thread pattern of the hole without making contact with undamaged internal threads therein. The application of mechanical means expands to the rethreader finger section to the exact diameter of the hole. During the expansion process the internal thread pattern of the hole and threading pattern of the rethreader finger section seat together. Rotation of the expanded rethreader finger section in the hole repairs the internal thread pattern of the hole to its original specified pattern. After completion of the rethreading process the rethreader finger section is collapsed by mechanical means and withdrawn from the internally threaded hole.

Abstract: A plug is used in welding a female-threaded boss into a hole through a part, the plug being installed in the boss prior to welding (preferably at the plant of the supplier of the bosses, so that they already have the plug installed when they arrive for welding). The plug has a head and a cylindrical portion extending below the head, the cylindrical portion having male threads adapted to be received by the female threads of the boss. The head has a minimum transverse dimension of at least the maximum transverse dimension of an upper surface of the boss so as to completely cover the upper surface. The cylindrical threaded portion of the plug has thread-cutting edges defined therein, configured to re-tap the threads of the boss when an installed plug is rotated in the direction necessary to remove the plug from the boss.

Abstract: A nib tap configuration in which the thread turns are of progressively increasing pitch diameter over a range of size limits associated with a standard basic pitch diameter. A particular size limit can be provided by grinding off the turns of a larger limit size. A family of taps covering an extended range of pitch diameter size limits allow selection over the extended range.

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 method of forming a threading tool for producing a thread of varying pitch in a work piece by relative rotary and axial movement between the tool and work piece. The tool is constructed to have a series of threading projections including a first series of pre-forming projections for initially producing a partial thread and groove in the work piece, and one or two final projections for reshaping the partial thread to have the varying pitch.

Abstract: A piloted hand tool adaptor for connecting a conventional rotary hand tool or rotary cutting tool to the chuck of a rotary-operated machine such as a lathe or drill press in order to provide mechanical axial support and alignment of the tool to a work piece while allowing manual rotation and advancement of the tool towards the work piece. One end of the adaptor has means such as a socket to attach to the butt-end and T-bar handle of a rotary hand tool such as a common tap handle. The other end of the adaptor has a two element axial support system such as a pilot and bushing, grippable within the chuck of the rotary-operated machine, which provides axial or lateral support and alignment without affecting manual control of rotational and longitudinal motion. The adaptor may have a supplemental detachable handle bar oriented perpendicular to the T-bar handle of the hand tool.

Abstract: Immediately behind a tap of an automatic threading machine to which nuts or like pieces are fed in succession, is a straight portion of a cast-off sheet coaxial with the tap and which is followed by an inclined portion including an obtuse angle with the straight portion. Another straight portion parallel to the first includes an obtuse angle with the inclined portion and guide passages are formed around the inclined portion and the final parallel portion in a head which is rotated to drive the tap. The nuts thus pass over the tap and the cast-off shaft and axial play of the cast-off shaft is minimized.

Abstract: A threading tap comprises a cylindrical shaft and a threading portion. At least the threading portion comprises a compound material comprising a core of high speed steel or tool steel and a cover of "Coronite".RTM., i.e., a hard material with 30 to 70% by volume of submicronic hard materials in the form of carbides, nitrides and/or carbonitrides of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and/or W in a metallic matrix based on Fe, Co and/or Ni. The chip surfaces adjacent to the cutting edges of the cutting threads have a negative rake angle. The threading tap has proven to be excellent at the threading of titanium-based alloys.

Abstract: A threaded hole (20) in a workpiece (22) is formed by rapidly spinning an elongated tool (24) having a drill point (64) at one end, at least one longitudinally extending flute (80) having thread milling faces (84) for milling the thread to be formed, and wherein the tool (24) is first moved axially to carry the drill point (64) against and into the workpiece (22) to form a hole (66), then is displaced radially a distance equal to the thread depth to be formed, then is moved orbitally around the hole (66) to mill threads therein, then is displaced back to the center of the hole (20) and then is retracted from the hole (20). To form a helical thread in the hole (20), the tool (24) is shifted axially one thread pitch during the orbital movement. A thread milling drill head (26) is disclosed for chucking the tool (24) and shifting it through the aforesaid movements.

Abstract: A combination tool is disclosed for drilling a hole in a workpiece on the inward feed of the tool and for threading the hole during retraction of the tool. The tool that has a straight body with a drill point at the forward end, a shank at the rearward end and a thread-form mill between the drill point and the shank.

Abstract: In a tap having a lead part and a complete thread part contiguous to the lead part, a relief is formed on at least one of a leading flank and a following flank of each of a plurality of thread ridges formed on the rear end side of the lead part and each of a plurality of thread ridges formed on the front end side of the contiguous complete thread part, so that the portion of an internal thread having been cut already by the preceding cutting edge may not be cut again and widened by the succeeding cutting edge.

Abstract: A process and apparatus for forming threads of varying pitch on a work piece, by first producing a partial thread and groove whose pitch does not vary in accordance with a pattern of pitch variation desired for the final product, and then reshaping the partial thread and groove to a final form whose pitch does vary in accordance with the desired pattern. The two steps may be performed by a single tool having a series of thread cutting projections which form the partial thread, and having one or two additional projections which then reshape the partial thread to its final form.

Abstract: A rotary tool connecting assembly is provided for use as a tap driver for transmitting torque to a tap. The assembly comprises an adapter receiver for receiving and securing a tap, a chuck body having one end which is detachably connectable to the spindle, and an opposing end having an axially aligned recess for slidably receiving the adapter receiver, and a mechanism for transmitting torque from the chuck body to the adapter receiver while allowing the receiver to freely axially slide within the recess of the chuck body that includes a plurality of linear roller bearings disposed between a single flat wall present on the side of the receiver and a flat bearing wall that defines a portion of the recess in the chuck body. The flat bearing wall of the chuck body is provided by a bearing insert which is compliantly seated within a slot in the chuck in order to keep its bearing wall parallel with the flat bearing wall of the adapter receiver when substantial amounts of torque are applied to the assembly.

Abstract: The invention provides an improved standardized blank adapted for making taps for making tapped holes and an improved positive lock tap holder. A standardized tap blank is provided which is standardized as to diameter, overall length, and shank length. Such a blank is adapted to manufacture a wide range of taps of varying thread sizes, both U.S. and British standards, and metric standard. For broadening the range of capacities that the blanks are adapted for, a set is provided including two additional standardized blanks, standardized as to a different diameter shank length and overall length. Each standardized blank is provided with a square end, standardized as to the square sides and overall length. The standardized tap blanks are further provided with an annular groove to for holding balls.

Abstract: A threading tool for repairing, in situ, threads within a bore of a head of an internal combustion engine without the danger of particulate waste falling into the engine housing. The threading tool can be used separately or in combination with a reaming tool for deburring, in situ, rough edges generally at the crest of threads within a bore of a head of an internal combustion engine without the danger of particulate waste falling into the engine housing.

Abstract: A combination tool is disclosed for drilling a hole in a workpiece on the inward feed of the tool and for threading the hole during retraction of the tool. The tool comprises a straight body with a drill point at the forward end, a shank at the rearward end and a threadform mill between the drill point and the shank.