Abstract: A stock lifter for metal forming dies includes a self-contained assembly. The assembly includes a guide pin that reciprocates within a base. A hardened end cap, which contacts the stock, is attached to the guide pin. A spring is located on the exterior surface of a portion of the base and surrounds the guide pin body. One end of the spring contacts a surface on the cap, while the other end of the spring contacts a surface on the base or an optional mounting flange that is attached above the base. Thus, the stock lifter assembly has a hardened cap for the stock to slide on and a larger, externally mounted spring that provides longer life for the stock lifter. The stock lifter assembly can be made of several different lengths and sizes by using longer or wider guide pins and springs.

Abstract: A twisted helically-shaped member (15) in the form of a twisted tie, twisted fastener, twisted wire or twisted rod; said twisted helically-shaped member (15) having an axial core (12) and a plurality of helical threads (13H) extending along the axial core (12); and wherein a variation in lead measurements along the length of at least one helical thread (13H), is less than a variation in pitch measurements along the lengths of the helical threads (13H); wherein the axial core (12) has a transverse cross-sectional area comprising two-fifths or less of the transverse circumscribed cross-sectional area of the helical threads (13H).

Abstract: An example terminal stud of a ram air fan connection assembly has a threaded portion extending from a head that is held within a slot of a base. The head has a sidewall that interfaces directly with the base. The sidewall has a length and a height. A ratio of the length to the height is from 2.18 to 2.35.

Abstract: A screw plug for a liquid conduit, particularly an oil pipe or an oil container, comprising a cylindrical shaft that is placed on a top plate and is provided with an external thread. A pocket hole having a polygonal cross section is centrally arranged on the top plate as a receiving member for a tool. The shaft is embodied as a tubular butt that is provided with the external thread. A pocket hole which is arranged coaxial to the pocket hole of the top plate extends from the face of the shaft. In order to produce the screw plug, a blank comprising the cylindrical tubular butt that is connected to the top plate in a molded on manner is made, the inner diameter and outer diameter of the tubular butt being smaller than the final corresponding diameters (e, f) of the screw plug. The tubular butt of the blank is then enlarged by applying pressure to the inner wall surface of the pocket hole thereof.

Abstract: Methods and apparatus for an asymmetrical fastening system according to various aspects of the present invention include a driver and a fastener that are configured to have corresponding conforming surfaces suitably adapted to provide substantially complete engagement between a torque surface of the driver and a recessed socket area of the fastener. The driver and fastener may each be configured to include a driving surface that is aligned with a longitudinal axis and a removal surface that intersects a radial extending from the longitudinal axis at an oblique angle. The driver and fastener may further include corresponding tapering surfaces that allow the torque surface of the driver to wedge against the recessed socket area of the fastener.

Abstract: This disclosure relates to a frangible fastener configured such that a first end of the fastener separates from a second end of the fastener responsive to a breaking force. The fastener may comprise a head portion, a frangible portion, a tool engagement portion, a threaded portion, and/or other portions. The frangible portion may include a frangible body. The frangible body may form a plurality of through wall cuts. The frangible portion may be configured such that the breaking force is proportional to a quantity of through wall cuts, a cross sectional area of through wall cuts, and/or a shape of through wall cuts. The frangible portion may be configured such that the breaking force is proportional to a wall thickness of the frangible body. The location of the tool engagement portion may minimize and/or eliminate torsional loading of the frangible portion during tightening with a tightening tool.

Abstract: A testing method for the bolt to be used under the conditions of excessive wind force by which bolts made of Cr—Mo steel can be separated into a group of bolts usable in cold areas and a group of bolts unusable in cold areas without conducting Charpy impact test involving complicated operation, specifically, a testing method for determining whether bolts made of heat-treated Cr—Mo steel are usable or unusable in cold areas, wherein the determination is conducted on the basis of both J parameter calculated by formula: J=(Si %+Mn %) (P %+Sn %) 104 (wherein P %, Si %, Mn % and Sn % are contents (mass %) of phosphorus (P), silicon (Si), manganese (Mn) and tin (Sn) respectively as disclosed in the inspection certificate of the Cr—Mo steel) and bolt diameter.

Abstract: A method for the production of torque-limited fastening devices, which each have a first head element with a contact for a fastening tool, and a second head element that is joined to the first head element via a welded joint that shears off at a predefined limit torque, said method providing a plurality of first head elements and second head elements having the same geometry, and in each case, a first head element and a second head element are welded together in a welding process that creates the welded joint. At least two welding processes are carried out employing at least one different welding parameter, so that different limit torques can be obtained for parts having the same geometry. A fastening device on a concrete anchor.

Abstract: A wire thread insert comprises besides a cylindrical helix consisting of a plurality of coils a moving tang projecting into the interior of the helix for installing the wire thread insert into a receiving thread. The wire thread insert is connected to the cylindrical helix via a bending portion such that the moving tang can be redressed into the receiving thread after installation of the wire thread insert. The wire thread insert is installed by means of an installation tool with a mounting spindle, which installs the wire thread insert in the receiving thread via a moving shoulder and the moving tang. A compression blade provided at the mounting spindle bends the moving tang back into the receiving thread while the mounting spindle is removed from the installed wire thread insert.

Abstract: Techniques for reinforcing concrete using rebar are disclosed. Some example embodiments may include prestressed concrete structures reinforced by twisted, threaded reinforcing bars. An example reinforcing bar for a prestressed concrete structure may include an elongated, generally cylindrical rod; an external thread disposed on the generally cylindrical rod, the external thread formed from an elongated, generally nonlinear channel wrapped about a radial surface of the generally cylindrical rod in a generally helical fashion. A base portion of the nonlinear channel may be disposed substantially against the radial surface of the generally cylindrical rod and/or an upstanding portion of the nonlinear channel may extend generally orthogonally from the radial surface of the generally cylindrical rod.

Abstract: By changing the timing of applying a heat treatment, a high-strength aluminum based alloy-made fastening part having an unprecedented tensile strength or other strength property and a method for manufacturing of the same are provided. The method is characterized in that an aluminum based alloy-made material is subjected to a solution treatment and is then age-hardened; work hardening is further applied to a shaft portion by drawing thereof in a heading process; and the shaft portion is thereafter subjected to a process of rolling male threads.

Abstract: Various embodiments described herein provide a fastener system having straight walled driving surfaces that provides a reliable stick fit feature, while also improving stability of engagement between the system components. A feature of the new system is to allow engagement of existing standard straight walled drivers in the new system.

Abstract: A die for roll forming threads on a cylindrical blank includes a planar die body having a longitudinally elongate working face of sufficient length for the blank to make multiple revolutions across the face. A plurality of thread forming elements on the face. The thread forming elements are spaced apart longitudinally of the die working face an ever increasing distance, based on the actual rolling diameter of the blank with the spacing between the thread forming elements at the start end equal to the diameter of the blank and the spacing between the thread forming elements at the finish end equal to eighty-five percent of the final diameter of the thread formed on the blank. The thread forming elements on the working face of the die are equally spaced apart in a direction perpendicular to the longitudinal extent of the working face.

Abstract: A method of manufacturing fastenings or fasteners with radial outer contours, especially screws or threaded bolts, made of solid metal is performed by a device. The method manufactures the fastenings or fasteners preferably on a multi-stage press. Several recesses running in an axial direction at a fixed radial distance are formed in the shank-shaped section of a blank. The prefabricated blank with the recesses is inserted into a multi-part split mold within a multi-stage press, whose die stocks have an inner profiling forming the outer contour, and are opened in the starting position, that at the places where the die stocks are opened, there are the recesses. During the closing movement of the die stocks, at least one radial outer contour is pressed on the shank-shaped section of the blank by radial action of forces, with the recesses preventing material from getting between the die stocks during the pressing process.

Abstract: A spiral fastener is provided. In another aspect, a spiral fastener, is made of layers of material and/or a light curable material. Another aspect uses a three-dimensional printing machine to emit material from an ink jet printing head to build up a fastener having a spiral formation.

Abstract: A shaft for anchoring in a vertebra or bone section is connected to a receiving part which serves to connect to a rod having a pre-determined diameter (D). The receiving part provides a U-shaped recess, forming a channel for the reception of the rod, and two legs. The legs are free on their ends and have a thread that cooperates with a securing element to fix the rod in the receiving part. When inserted into the receiving part, the rod surface facing an end surface is at a pre-determined distance (A) in an axial direction from the end surface. The thread of the legs extends from the end surface a distance that is smaller than or equal to the pre-determined distance (A). Also, an undercut is provided adjacent to the thread whose edge farthest away from the thread is located at a distance (B) from the end surface.

Abstract: A thread forming screw having a minimum surface hardness of HRC 56. The screw can form threads in a workpiece having a surface hardness which exceeds HRC 23. A method of surface hardening a screw includes carbon enriching the screw to at least a 0.48 carbon level, and then quenching the screw. Then, the screw is tempered such that the surface hardness does not exceed the core hardness by more than 3 Rockwell C points, and both the surface and core are at a Rockwell C33-C39 hardness. Subsequently, the point is induction hardened, and the screw is quenched again. The screw is again tempered such that the lead threads and the first 3-4 full threads are at a Rockwell C56 minimum hardness, preferably to a depth of at least 0.008 inches, and the core of the fastener is at Rockwell C33-C39 hardness. Finally, a finish is applied.

Abstract: A threaded element in the shape of a wire thread insert with a specific geometric design is disclosed. This threaded element contains, in particular, a narrowed helical winding of at least two helical winding sections that enclose one or a plurality of sequential secants. Based on this geometric design of the threaded element, a matched installation process is described.

Abstract: A two-piece guide pin for metal forming dies includes a guide pin body formed from a cut length of an elongate, solid bar of stock having a cylindrical shape and a hard and smooth finished exterior surface with an outside diameter selected for close reception and reciprocal motion in an associated die bore. An alignment member is formed on a first end of the guide pin body. A guide pin head is formed from a cut length of an elongate, solid bar of stock having an outside diameter that is substantially greater than that of the guide pin body, and is rigidly connected with the second end of the guide pin body in a generally concentric relationship to define an enlarged head that positively limits travel between an associated die shoe and die pad.

Abstract: A method and apparatus for molding a high-strength, non-metallic fiber-reinforced threaded fastener, such as a bolt or the like. A non-metallic preform (e.g., a solid rod) having longitudinally-extending fibers running therethrough is located in a mold. A mold insert is positioned at the top of the mold, and a penetrator having a pointed tip is located at the bottom of the mold. Upper and lower press plates are closed against the mold insert and the penetrator. Accordingly, the upper press plate moves the mold insert against the top of the preform in the mold to form the bolt head. The lower press plate moves the penetrator against the bottom of the preform, whereby the penetrator is embedded therewithin. By virtue of the embedded preform, the molded fastener will have axially-extending fibers which are compressed into the threads and run in substantially parallel alignment to better resist failure under load conditions.

Abstract: Various embodiments described herein provide a fastener system having straight walled driving surfaces that provides a reliable stick fit feature, while also improving stability of engagement between the system components. A feature of the new system is to allow engagement of existing standard straight walled drivers in the new system.

Abstract: A corrosion-protected, self-drilling anchor and an anchor subunit and to a method for the production thereof is provided. A self-drilling anchor of the invention includes a number of anchor subunits, each with a hollow bar element, which are connected together by the formation of an axial bell butt joint to form a connected pull and pressure member. The first subunit t its end has a drill bit and the subunit is connected non-rotatably with its end to a drilling and injection device. It is provided according to the invention that each hollow bar element is surrounded by a sheathing except for its end sections and the annular gap between the sheathing and hollow bar element is grouted with a first corrosion protection compound. A coupler in the area of the bell butt joint fits tightly against the sheathings of the two hollow bar elements which are part of the bell butt joint. The hollow space between the coupler and hollow bar elements is filled with a second corrosion protection compound.

Abstract: A formed product, characterized in that it is produced by using, as a material, a steel having an ultra fine structure comprising ferrite grains having an average grain diameter of 3 ?m or less and by a method comprising only a forming step and including none of refining steps; and a method for producting the above formed product with ease. The formed product contains no alloying element and has been subjected to no refining step, and has been imparted with high strength and high toughness by the above ultra fine structure.

Abstract: Interference surfaces are constructed on inner transition surfaces between wings of a fastener having a spiral recess. A portion of the transition surface is tapered to provide the interference. A standard driver for a spiral recess will engage the interference surface to create a “stick fit” engagement. The punch is formed using a wire EDM operation to construct tapered surfaces within the die cavity of a hob. The hob is machined down to obtain the desired depth, which is measured up from a gage spot indicative of the sticking point.

Abstract: In mounting a resin panel to a car body member, the car body member is provided with a car body member thread part, a portion of the resin panel corresponding to the car body member thread part is formed with a slot extending along a direction of allowance of thermal deformation of the resin panel, and the resin panel is mounted to the car body member using a fastener including: a threaded stem; a first large diameter part provided to one end of the threaded stem and insertable in the slot; and a fastener thread part provided at an end surface of the first large diameter part opposite to the threaded stem and screw-engageable with the car body member thread part.

Abstract: Interference surfaces are constructed on inner transition surfaces between wings of a fastener having a spiral recess. A portion of the transition surface is tapered to provide the interference. A standard driver for a spiral recess will engage the interference surface to create a “stick fit” engagement. The punch is formed using a wire EDM operation to construct tapered surfaces within the die cavity of a hob. The hob is machined down to obtain the desired depth, which is measured up from a gage spot indicative of the sticking point.

Abstract: The fastener of this application is designed to facilitate the insertion of rotating power driven tools into the fastener recess. The recess of this fastener generally uses spirally configured driving surfaces and is formed in a counterbore in the upper surface of the fastener. The driving lobes have upper surfaces that are depressed a distance into the counterbore. A ramp surface is formed on each of the upper surfaces that causes a spinning bit to fall into the recess in an engaged manner. The ramp surfaces are constructed with both removal and installation ramp portions.

Abstract: A self-tapping screw includes a head, a shaft, a tapered end and a rounded distal tip. A thread includes a thread start on the tapered end. The axial position of the thread start and a first full thread, the radius of the round distal tip and the diameter of the tapered end at the thread start are controlled in relation to the screw size for consistent, improved screw performance.

Abstract: The present invention relates to a method for manufacturing a bolt that includes an axis, including the steps of providing a metal rod, providing a die, extruding the metal rod through use of the die, cold forming the metal rod, at least in part, to provide a shaft and a head so that, the head includes a torque transferring structure, the head includes a flange located adjacent to the torque transferring structure, a generally cylindrical surface is located adjacent to the flange, and a sloping surface that extends from the generally cylindrical surface towards the axis, rolling a threaded surface into the shaft, and providing a plurality of grooves so that the grooves extend from an end of the bolt.

Abstract: A method for making a ball-nut includes cutting a 360-degree closed-loop surface groove in the inner-circumferential wall portion of a ball-nut body using a whirling-type internal-diameter cutting machine. The closed-loop surface groove surrounds the longitudinal axis of the wall portion, is adapted for receiving a plurality of ball bearings, includes a helical-grooved portion substantially coaxially aligned with the longitudinal axis, and includes a crossover-grooved portion. A method for making a ball-screw includes cutting at least one 360-degree closed-loop surface groove in the outer-circumferential wall portion of a ball-screw body using a whirling-type external-diameter cutting machine. The closed-loop surface groove surrounds the longitudinal axis of the wall portion, is adapted for receiving a plurality of ball bearings, includes a helical-grooved portion substantially coaxially aligned with the longitudinal axis, and includes a cross-under-grooved portion.

Abstract: In a process for the production of a screw comprising a low-alloy carbon steel, having a head, an adjoining holding portion and a functional tip which, in the outer region of limited radial depth, is of a greater hardness than the holding portion, in which the screw body is shaped by pressing and rolling and then the functional tip is subjected to a hardening operation, hardening is effected by momentary heating with a high level of energy transfer and subsequent quenching and is limited to portions of the periphery of the functional tip.

Abstract: The invention relates to a tissue anchor which is an open helix of biocompatible material having a slope of from 0.5 to 10 turns per centimeter, a length from 3 to 75 millimeters, a diameter of from 1.5 to 11 millimeters, and an aspect ratio of from about 3 to about 5 to 1. The anchor can have a head which is capable of securing or clamping tissue together, such as holding a suture to secure a ligament or tendon to bone. The anchor can also have a head which causes an inward, compressive loading for use in fastening bone to bone, orthopedic plates to bone, or cartilage to bone. The head may be an integral member and may include a self-reinforcing wedge which joins the helix to the head. Further, the elongate member, or filament that forms the helix may have a tapering diameter along its length.

Abstract: The novel concept to be patented involves minutely indenting the standard fasteners along the pitch line at various points and utilizing the small material deformations around these indentations to provide substantial engagement to resist loosening of the joint under operational loads. The basic idea is to stamp a typical pattern (two are described below) on the fastener to achieve the advantages of a self-locking mechanism as well as enhance the torque and load carrying capability of the joint. Moreover, the indentations being in the order of few mils would not degrade the strength of the fastener, but would continue to provide sufficient load transfer across the joint without loss of preload. Furthermore, the joint can be disassembled and the fasteners can then be reused for the subsequent operations. These unique indentations on the fasteners can be of varying numbers, depths, geometry (spherical, elliptical etc.) and of various patterns (linear, staggered etc.

Abstract: A fastener is described having a head formed with a recess which accommodates a square head driver, symmetrical drivers, such as PHILLIPS™ style drivers, asymmetrical style cross head drivers, such as POZIDRIV® style drivers, and combination square and cross drivers without compromising performance of the drivers.

Abstract: The present invention relates to apparatus and process for roll forming a fillet at the juncture of the shank and head of a pin type fastener. The process and apparatus can be preset to perform the fillet rolling at selected parameters and to monitor the parameters for providing parts with uniformly rolled fillets.

Abstract: A cool-wrought pressing forming method for slotted headless screws includes five steps of using five different molds and five pressing heads for processing a unit of screw material cut from linear material for forming an unfinished screw with a slot in an upper end. A clamping member is provided for clamping a screw material for moving it from a first mold in a first step to a second mold in a second step after pressed by a first pressing head and then from a second step to a third mold in a third step, and so forth. The slot of a screw is formed by pressing to make the slot neat and without any hairy sides and look very flat, enhancing production effect and lowering cost.

Abstract: A method of making a UHMWPE body combined with a bolt, a cap screw, a reinforcing member uses a compression molding machine equipped with a male and female mold set. Particulate UHMWPE dispensed into the cavity of the female mold surrounds the head of the bolt and screw and reinforcing member. Pressure and heat applied to the particulate UHMWPE molecularly bonds the UHMWPE to the bolt, screw, and reinforcing member.

Abstract: A method of making a recess in a drive socket and the like includes forming a groove to extend along a face of an elongated drive opening in a metal workpiece from one end of its drive opening, moving material from the surface of the groove to increase its depth from its outer end along only a portion of its length and gathering the material so moved from the groove surface to form a ledge between ends of the groove, whereby a recess is defined by the groove extending beyond the ledge. In addition, a female drive device for socket wrenches and the like is disclosed having an elongated drive opening, a groove longitudinally extending from one end of the drive opening along a face of the drive opening, and a ledge between ends of the groove. The ledge protrudes radially inwardly such that a recess is defined by the groove extending beyond the ledge for retaining a male drive member.

Abstract: A method for manufacturing of fastening elements (5, 6) and including producing a blank (1) having a length exceeding a combined length of two fastening elements, upsetting a head (2, 3) at each of opposite ends of the blank (1), heating a section of the blank (1) located between the opposite heads (2, 3) formed at the opposite ends of the blank, and, thereafter, pulling apart the heated section (4) until the heated section (4) is separated.

Abstract: The slotted screw is made with an apparatus for forming a slot in a semi-product of a screw prior to thread formation and includes a punch and a die mechanism. The die mechanism includes a tubular member, and an elongated die member formed integrally with a slot-forming plate which is located at a front end portion thereof and which has a uniform-thickness flat middle portion and two side portions that are wider than the middle portion. The semi-product can be compressed between the punch and the slot-forming plate of the die member in a central bore in a high-hardness block, which is fixed in the tubular member, to form the slot. Accordingly, the slot has a uniform-width middle portion and two end portions which are wider than the uniform-width middle portion.

Abstract: A method for heat treating a metal article such as a fastener comprising the step of case hardening the fastener in a gas carborizing atmosphere at a temperature of about 1700° F. or in a carbonitriding atmosphere at a temperature of about 1550° F., and quenching the fastener in water or oil and tempering the fastener at a minimum temperature of 770° F. for approximately one hour.

Abstract: A method of fastener identification for traceability of manufacturing information of an individual fastener, is achieved by applying a code to the fastener. The fasteners to be identified typically are formed of hardened materials such as steel. A die cast, forged or pressed roll stamp or forge stamp is thus used to apply the code and is formed with a raised stencil of one or more characters or indicia. Multiple lots of a certain fastener typically are manufactured in a given time period, such as a year, thus requiring a different code to identify each fastener lot. Numbers of lots and sizes of individual lots for a given time period are difficult to predict for a fastener producer, thus risking waste if multiple customized stamps are used to identify the lots. A universal stamp having a single indicia stencil is utilized to identify all lots of a certain fastener in a given time period, by removing selected ones of the stencil characters from the universal stamp for each different lot.

Abstract: A male screw which has a protrusion protruding from a thread thereof at least with regard to the normal direction to a flank of the thread. To obtain such male screw, a blank is introduced between rolling dies which are moved relative to one another and is rolled between the rolling dies to be formed with a thread. In this thread rolling process, the rolling pressure on an area of a die face of at least one of the rolling dies is determined to be higher than that in an ordinary thread rolling process and the rear end portion of the area of the die face is made to bite into the blank, causing the corresponding portion of the blank to be forced out to form the protrusion.

Abstract: In a first embodiment, a method for forming a hardened fastener having a hardened fastener head. Alloys made of cobalt, nickel, chromium, and molybdenum have very high hardnesses while maintaining ductility. Metals conforming to the chemistry of AMS 5844 and AMS 5842 are disclosed as the preferred materials. These hardnesses are also maintained at high temperatures. In order to form a head upon such materials, a fastener blank is first initially hardened by cold reduction twenty to thirty percent (20%-30%). A fastener head is then formed in the fastener blank by additional cold forging. The remaining shank portion of the fastener blank is cold worked in a third process with the entire three-part cold forging process cold reducing the material forty-eight to fifty percent (48%-50%). Additional hardness may be obtained by heating the material in a temperature range between ca. 1200.degree. F. and 1300.degree. F.

Abstract: A method of forming an apparatus having a captured washer includes the step of forming a shaft with a first end, a second end, a shaft diameter, and an axis. A stop element is provided on the shaft. An integral washer is formed on the shaft spaced from the stop element. The washer has a thickness and a diameter greater than the shaft diameter. The washer extends generally perpendicular to and radially outward from the shaft. The washer has a first surface facing the stop element and opposite surface facing opposite the first surface. A button is formed on and extends axially from the washer opposite. The button has a diameter greater than the shaft diameter and less than the washer diameter. A groove is formed into the first surface of the washer and defines a washer opening having an inside diameter less than the button diameter. The groove is formed so that the washer remains attached to the button by a material bridge extending between the button and.

Abstract: A method of manufacturing a connector bolt includes the steps of forming axial grooves on a part of the shank of the connector bolt, and then simultaneously performing a rolling process for thread formation around the shank part with the axial grooves formed thereon with a rolling tool and a different rolling process around a part of the shank without the axial grooves with a different rolling tool.

Abstract: A method of making a shaft abutment screw, especially for axial engagement with an armature shaft of an electric motor, includes the following steps:(a) pressing out a flat mild steel blank,(b) subjecting the blank to a drawing operation so as to form a hollow component comprising a generally flat radial base wall and a generally cylindrical skirt portion extending from the base wall and describing a screw driving socket within it,(c) machining a screw thread on the outside of the skirt portion, and then(d) nitriding the component.A shaft abutment screw having a flat base portion joined to an externally threaded cylindrical skirt portion, within which a hexagonal screw driving socket is formed, is also described per se. The invention is applicable especially to motorised reduction gear units for driving motor vehicle screen wipers for windshields and rear windows.

Abstract: The invention relates to thread formation and particularly to the formation of threads on deformed steel reinforcing rods. The method of forming a thread on the steel reinforcing rod comprises the steps of cold upsetting an end region (1) of a deformed steel reinforcing rod having a nominal diameter, the upsetting being arranged to increase the diameter of the end region to a new, upset, diameter greater than the nominal diameter, rolling a thread onto the end region (1) so as to produce a threaded region having a thread major diameter which is greater than the nominal diameter and a thread minor diameter which is less than the nominal diameter. The formation of such a thread enables the production of mechanical connections between pairs of rods, the connections having a strength greater than that of the rods being connected to one another.

Abstract: A fastener has a head and a shank with two ends. One of the ends includes the head while the other includes a pilot point. Also, the shank includes a threaded portion adjacent to the pilot point. A pair of recesses are formed 180.degree. from one another on the point and threaded portion. The recesses extend from the end of the point through at least a first full thread.