Abstract: There is provided a screw for fastening a wooden member which includes: a shank that extends along a datum line; a head that is disposed at an end of the shank and has a plate portion having a cross-section that narrows as it goes to the shank such that the boundary of the cross-section and the datum line make a plate angle; and a tapered blade that protrudes from the outer side of the plate portion, has a bottom perpendicular to the datum line and a side making an obtuse angle with the bottom, and has a taper angle that is made by the side and the datum line and is 2.50° to 12.5° smaller than the plate angle.

Abstract: A fastener includes a cylindrical shaft, a screw head located at an uppermost portion of the cylindrical shaft and comprising a tool indentation therein, a threaded portion on the cylindrical shaft comprising a plurality of external threads, and a countersinking portion located between the threaded portion and the screw head and comprising a cutting section. The countersink portion is tapered from a first diameter equal to a diameter of the threaded portion to a second diameter that is equal to or larger than a diameter or a maximum width of the screw head. The countersinking portion is configured to form a countersink hole in a receiving material as the fastener is rotated and forced into the receiving material.

Abstract: A wave threaded fastener and system. A wave thread extends from the outer surface of the body and is made up of a profile wave and a lateral wave. The profile wave includes a plurality of profile crests and profile roots defining a plurality of profile thread widths. The lateral wave includes at least one lateral crest and at least one lateral root defining at least one wave period. Each wave period forms a period arc having a period arc angle and the sum of all period arc angles about the lateral wave equals three hundred and sixty degrees. Each of the profile crests and roots are aligned with corresponding lateral crests and roots and the wave thread travels one profile thread width per each period arc traveled.

Abstract: A threaded fastener includes a shank having a first, threaded portion and a hardened thread portion. The shank includes a thread extending outwardly from a shank body over a first length of the shank. A second portion of the shank includes a groove positioned coincident with the thread and including a turn ratio equal to a turn ratio of the thread. The shank comprises corrosive resistant stainless steel. A coil of hardened steel engages the groove to fill the groove along the second portion.

Abstract: A screw coupling between two bodies, one having an external screw thread and another having an internal screw thread complementary thereto, which screw threads are superimposed onto two base surfaces monotonously narrowing and widening respectively in the direction of a central axis, the longitudinal section of each of these screw threads relative to the central axis being a periodic univalent function which is continuous at least at the inflection points. The screw coupling has the following features: the first and second derivatives of the longitudinal section of each screw thread along the base surface is a continuous function; the second derivative of the longitudinal section of each screw thread relative to the central axis is a continuous function at least in the region of the inflection points; and the screw threads are in mutual contact over a substantial surface area differing from line contact.

Abstract: Non-dimpling fasteners and methods of installing non-dimpling fasteners are provided herein. Non-dimpling fasteners can include a body including a first end and a second end, a tip at the first end of the body, a head at the second end of the body, a first body portion adjacent to the tip, a second body portion adjacent to the head, and a shoulder adjacent to the first body portion and the second body portion. The first body portion can have a first diameter and can include a first thread. The second body portion can have a second diameter that is larger than the first diameter of the first body portion. The shoulder can have an angle with respect to a longitudinal axis of the fastener.

Abstract: A hole-forming and thread-forming screw for screwing into a sheet piece, including a slotted screw head for accommodating a tool, a threaded shank and a tapering hole-forming part having outer sides with a continuous convex-shaped curve along an entire length thereof, ribs running like threads along the hole-forming part being provided. The hole-forming part ends in a rounded, blunt end piece, and the rounded ribs, which chiplessly displace the material of the sheet part, are situated symmetrically opposite one another and have a pitch that is a multiple of the thread pitch.

Abstract: A bolted connection for connecting two wind turbine components by bolts is proposed. Each of the bolts has a shaft and a plurality of threads. A transition region between the bolt shaft and the bolt threads is tapered. The bolted connection can be used to connect a rotor blade to a blade bearing of a wind turbine.

Abstract: A self-drilling fastener for use in a friable material with or without an underlying member at the point of use comprises an elongated body, a threaded exterior, an enlarged head with torque transmitting surfaces, proximal, intermediate, and distal portions, and a drilling tip generally opposite enlarged head. Proximal portion has an axial length, a threaded exterior having root and crest diameters and a thread height, where the crest diameter is about twice the root diameter. Intermediate portion has an axial length, a threaded exterior having a root, a crest diameter substantially smaller than proximal portion crest diameter and a thread height substantially smaller than proximal portion thread height. Distal portion has an axial length, a threaded exterior with a root that tapers toward the drilling tip, a crest diameter substantially smaller than the proximal portion crest diameter, and a thread height substantially smaller than the proximal portion thread height portion.

Abstract: A screw which can be manufactured at a low cost with a relatively simple constitution by performing precise machining suitable for tightening a screw without employing a tapping thread structure as a threaded portion shape and machining only the distal end of the threaded portion to have a shape projecting spherically, and which can ensure smooth and quick screw tightening work without causing such problems as heat generation or molding powder at all at screw tightening. The screw includes a head (12) provided with a bit fitting groove (13) at one end, and a threaded portion (14) which is machined precisely with substantially equal circular diameter over a full length, wherein the distal end (20) of the threaded portion (14) is shaped to have a spherical projection varying in a plurality of stages.

Abstract: A screw for the creation of a metric thread in a female element, includes a load-bearing (metric) thread portion and a forming thread portion which is tapered to the tip of the screw. The flights of the tapered thread portion are sharp-edged and fully formed.

Abstract: The present invention comprises a neck extending upwardly from a container and having an upper rim defining a neck opening. The neck has a substantially vertical sidewall of a constant thickness and at least one container neck thread extending from the sidewall. The at least one neck thread has an outer thread face drafted from a radially inward upper position to a radially outward lower position. The device further comprises a closure having a top wall and a skirt depending from the top wall, wherein the skirt is tapered. The closure comprises a closure thread extending helically along an inner surface of the skirt. The container thread has increasing radial length moving downwardly along the container neck.

Abstract: A screw which can be manufactured at a low cost with a relatively simple constitution by performing precise machining suitable for tightening a screw without employing a tapping thread structure as a threaded portion shape and machining only the distal end of the threaded portion to have a shape projecting spherically, and which can ensure smooth and quick screw tightening work without causing such problems as heat generation or molding powder at all at screw tightening. The screw includes a head (12) provided with a bit fitting groove (13) at one end, and a threaded portion (14) which is machined precisely with substantially equal circular diameter over a full length, wherein the distal end (20) of the threaded portion (14) is shaped to have a spherical projection varying in a plurality of stages.

Abstract: Disclosed is a taper bolt connection including a taper bolt received in a taper bush, a fastening nut and a washer, the taper bush having a continuous longitudinal slot, and the taper bush being capable of being spread open uniformly in the radial direction by means of a fastening nut screwable onto the taper bolt. Since the taper bolt and/or the taper bush have/has, at least in regions, an at least Teflon-containing coating, tribochemical processes between the taper bush wedge surface and the taper bolt wedge surface are largely avoided, so that the taper bolt connection can be released again without great effort even after a long period of connection. Furthermore disclosed is the use of the taper bolt connection for connecting a rudder unit to a carrying structure of a fuselage cell of an aircraft.

Abstract: A fastening device for a heat sink includes a one-piece shaft. The shaft includes a head at one end thereof, an engaging section at an opposite end thereof, a connecting section between the head and the engaging section, and a tray extending above the engaging section. A spring surrounds the connecting section between the head and the tray of the shaft. A gasket engages with the connecting section of the shaft and is retained between the spring and the tray of the shaft. In this way the shaft, the spring and the gasket are assembled. The gasket extends a downward, annular sidewall for engaging in the heat sink, by which the fastening device can be stably fixed to the heat sink. A back plate extends a nut toward the shaft for engaging with the engaging section of the shaft.

Abstract: A threaded fastener and threaded fastener system. The threaded fastener includes a body having at least one outer surface and at least one thread forming a spiral about the outer surface of the body. The thread forms a plurality of crests and a plurality of roots and the tangential distance between adjacent crests is substantially constant. The threaded fastener system includes the threaded fastener and a workpiece with an opening having at least one inner surface dimensioned to mate with outer surface of the threaded fastener.

Abstract: A fastening device for joining together mechanical parts is provided, where the fastening device includes integrated cutting edges that are so arranged, during assembly of the fastening device, as to remove material from the envelope surfaces of the assembly hole by cutting in a rotating movement, so that the assembly hole is caused to fit the envelope surface of the fitting part. A fastening device can be provided which, by simple and inexpensive means, is so arranged as to absorb both shearing loads and tensile/compressive loads arising between the joined parts.

Abstract: Improved bone anchors are disclosed for anchoring one or more sutures attached to soft tissue to a bone. The bone anchor has an anchor body that extends between a distal and a proximal end. A bore is formed axially in the anchor body and opens at the proximal end. One or more pins are fixed within the bore of the anchor body. One or more sutures can be looped on the pins for anchoring soft tissue to bone. The anchor body has a socket within the bore for receiving a driver tool. The distal end of the anchor body forms a non-threaded extension, which stabilizes the bone anchor, and helps prevent lateral movement during use. In one embodiment, the anchor body has coarse threads for engaging soft bone tissue and fine threads for engaging hard bone tissue.

Abstract: An improved dual threaded fastener for composite materials having a head and a shaft. The head is affixed to one end of the shaft and the shaft includes a point at its other end. The shaft includes an upper threaded portion and an upper threaded portion. The diameter of the shaft within the lower threaded portion is greater than the diameter of the shaft within the upper threaded portion. In this manner, as the fastener is rotated within the workpiece, producing remnants may be stored in the area surrounding the upper threaded portion.

Abstract: Screw made of plastic for screwing into a material of low strength, e.g. rigid foam plastic, having a deep thread compared with the screw shank, the screw shank running out conically into a screw point. The screw has the following features: 1. the depth of thread H and the minor diameter Dk of the thread form a quotient Q1=H/Dk in the order of magnitude of 1 to 3.5, preferably 2; 2. the minor diameter Dk and the thread pitch P form a quotient Q2=Dk/P in the order of magnitude of 0.3 to 0.6, preferably 0.5; 3. the thread is designed as a V-thread having a vertex angle of the thread teeth of less than 30°.

Abstract: A screw form anchor device (10) intended for screwed penetration into a host material. The anchor device (10) includes a body (11) having a manipulating end (12) and a distal end (13). A screw thread (22) is formed by a plurality of tapering angular helix thread forms (22a) which extend from the distal end. Each angular helix thread form (22a) has an outward facing surface (24) and, relative to the distal end, a downward facing surface (25). In the preferred form an emergent helix thread (26) commences from a point distant from the distal end (13). This emergent helix thread (26) extends toward the manipulating end (12) of the body (11).

Abstract: A bolt is provided with a head part and a shank part. The shank part includes a first constant diameter cylindrical part, a transition part, a cylindrical connection part, and a second constant diameter cylindrical part concentrically extending from the first constant diameter cylindrical part to the second constant diameter cylindrical part. The first constant diameter cylindrical part has a screw thread with a predetermined pitch formed on the side surface thereof. The transition part has a tapered shape and has a screw thread with a predetermined pitch formed on the side surface thereof. The cylindrical connection part has a diameter smaller than that of the first constant diameter part. The second constant diameter cylindrical part has a diameter smaller than the first constant diameter part, and has a screw thread with a predetermined pitch formed on the side surface thereof. The crest part of the screw thread formed on the side surface of the transition part is truncated.

Abstract: A threaded self-tapping screw for joining thin workpieces having a tapered root portion adjacent to the head of the screw. A plurality of threads are disposed on the body and the tapered root portion of the screw such that the radial distance from the center of the screw to the crests of the threads is maintained along both the body and the tapered root portion.

Abstract: The present invention relates to a novel screw for use with dry wall and for hanging articles therefrom. This invention provides a screw with a head adapted for engagement with a driving tool, a shank whose diameter decreases from the head to a distal end, and a helical thread with a pitch diameter of at least about twice the largest minimum diameter of the shank. The thread including a geometry of an auger.

Abstract: A suture anchor for facilitating the anchoring of soft tissue to a bony site includes a distal sharpened tip, and intermediate threaded section and a proximal drive head. The drive head is configured to receive a socket drive tool and has a suture-receiving eyelet formed therethrough. The threaded section is defined by a crest taper angle that is greater than the root taper angle.

Abstract: A self-tapping fastener is provided. The fastener is formed from a blank having an odd number of lobes along a cross section taken perpendicular to its axis of rotation. The lobes define a relatively high out-of-round cross section along a tapered thread-forming zone, and a relatively low out-of-round cross section along the main body taken in a direction toward the drive head. Between the main body and tapered thread-forming zone is located an additional thread forming zone having an axial length of approximately one thread pitch and a cross section that conforms to the high out-of-round of the tapered zone. The maximum diameter (at the lobes) of the additional thread-forming section approximately matches that of the full-diameter main body section. A lower-diameter stabilizing section can be provided ahead of the tapered zone, adjacent the tip of the fastener.

Abstract: A self-drilling, self-tapping screw for concrete blocks which includes a shank having a proximal portion equipped with a double lead, self-tapping spiral thread and an unthreaded portion which connects the threaded shank portion to a carbide drill tip in an axially spaced relationship. The length of the unthreaded portion of the shank is selected to allow the drill tip to form a clearance hole extending through the concrete block prior to engagement of the threaded shank portion with the clearance hole.

Abstract: An anti-cross threading fastener having a threaded shaft portion with a major diameter and a minor diameter, a leading end shaft portion devoid of screw threads and having a diameter less than the major diameter of the threaded shaft portion. The leading end shaft portion also includes a tip having an at least partially substantially curved surface, and a groove disposed about the shaft portion between the tip portion and the threaded shaft portion. A cylindrical shaft portion may be disposed between the tip portion and the groove. A portion of the threaded shaft portion tapers narrowingly toward the tip portion thereof, and the screw threads of the tapered threaded shaft portion have a flank angle greater than a flank angle of the screw threads of a non-tapered threaded shaft portion. The tapered screw threads may be formed of spaced apart lobes.

Abstract: Disclosed is a bolt which has been contemplated to solve problems of prior bolts and to provide the bolt adapted to corrects its own position in a precise direction to permit normal fastening without failure such as slipping, seizure or the like even when the bolt is inserted slantingly into a mating female screw. The bolt comprises a constant diameter columnar portion having a smaller diameter than that of a bolt shank portion and formed on an end portion of the bolt shank portion, formed with normal screw threads, in a direction of insertion with a short tapered portion therebetween, and complete screw threads formed on the constant diameter columnar portion to be equal in pitch and thread groove depth to the normal screw threads on the bolt shank portion.

Abstract: A blank for a self tapping fastener, and corresponding fastener is provided. The blank defines an odd number of lobes along a cross section taken perpendicular to its axis of rotation. The lobes define a relatively high out-of-round cross section along a tapered thread-forming zone, and a relatively low out-of-round cross section along the main body taken in a direction toward the drive head. Between the main body and tapered thread-forming zone is located an additional thread forming zone having an axial length of approximately one thread pitch and a cross section that conforms to the high out-of-round of the tapered zone. The maximum diameter (at the lobes) of the additional thread-forming section approximately matches that of the full-diameter main body section. A lower-diameter stabilizing section can be provided ahead of the tapered zone, adjacent the tip of the fastener.

Abstract: The spacer screw has a first thread section (1) which can be screwed into a base element, a head section (3) which can be introduced into the construction element, a shank section (2) formed between the head section and the first thread section and a recess for the insertion of a tool. A second thread section (4), is additionally formed between the anchoring section and the shank section and has the same core diameter as the anchoring section (6). When using the spacer screw the head section (3) is drawn into the construction element by the second thread section (4) independently of the turning in of the first thread section (1), so that on the one hand the adjustment of the spacing between the base element and the construction element can take place without special measures and, on the other hand, the screw can be used independently of the differences in strength of the base element and the construction element.

Abstract: Bone screw for osteosynthesis devices comprising a screwing head and a screw-threaded shank having a transition portion having a variable profile between two shank parts of different profiles. The threading has a constant pitch and a constant outside diameter, and includes cutting crests throughout its length, including in the transition region. According to one method for manufacturing this screw, there are machined on the transition portion of the shank threads of decreasing depth up to the end of this transition region, the threads along the transition portion defining truncated, non-cutting crests. There is removed from the threads on the transition portion a sufficient amount of material for converting the non-cutting crests into sharp, cutting crests. This method provides a screw with bone anchorage capability throughout the length of the thread.

Abstract: A bolt provided with a pilot of the present invention is formed with a pilot portion, on the front end side of a shank portion, having an axis aligning with an axis of the shank portion. The pilot portion is formed with a guide thread portion continuous to the normal thread portion to about half portion of the pilot portion. The connecting portion between the normal thread portion and the guide thread portion has a connection thread portion having an outer diameter gradually reducing from the normal thread portion toward the front end portion of the pilot portion. According to such structure, workability can be improved.

Abstract: A method and apparatus for repairing a casting in a cold metal repair process includes a plurality of drilling fixtures which facilitate the creation of one or more lock receiving recesses positioned generally transverse to the casting crack. The lock receiving recesses are formed of a single sized circular bore combination having alternating double and single circular portions to maximize strength. A plurality of correspondingly configured metal locks are inserted into the lock receiving recesses to provide transverse metal locks drawing the casting portions on each side of the crack together. A plurality of threaded bores are formed along the remainder of the casting crack in overlapping spacing which receive a corresponding plurality of stitching pins. The stitching pins each define threaded shaft portions having pointed ends and undersized major pitch diameter threads adjacent the pointed ends.

Abstract: A lead-in point on an end of an externally threaded fastener has a shape in any axial section defined by a curve tangent to the inside of a cylinder formed about the thread axis. The cylinder is of a diameter smaller than the smallest permissible minor (inner) diameter of a mating internal thread, but preferably larger than the minor diameter of the external thread. The length of the lead-in point is preferably from one to three thread pitches. The curved surface of the lead-in point is such that at any practical angle of insertion (where thread engagement is possible), the dimensional characteristics of the lead-in point present only a curved surface (not an edge) for possible contact with the internal threads. This length also insures that the end of the fastener is small enough to feed into internal threads at all angles where such thread contact is effective in producing a threaded joint.

Abstract: In a fastener having a head and a shank having a generally cylindrical portion with a proximal end adjoining the head and with a distal end, the shank has a primary thread formation and a secondary thread formation. The primary thread formation has a generally uniform radial dimension along the generally cylindrical portion. In one embodiment, the secondary thread formation has a radial dimension tapering outwardly so as to increase continuously from a region where the secondary thread formation originates near the distal end to a region where the secondary thread formation has a maximum radial dimension, which is equal approximately to the generally uniform radial dimension, the latter region being closer to the distal end than to the proximal end. If the secondary thread formation is interrupted, tapping torque is lower, as compared to tapping torque if the secondary thread formation is continuous.

Abstract: A screw having a root and threads formed on the root. The screw is configured to generate and/or maintain axial compression between threads formed in leading and trailing sections of the screw either by virtue of pitch differential in the threads or the way in which the screw is installed.

Abstract: A bone screw having a continuously varying pitch includes a tapered root portion having a relatively small diameter on a leading end of the screw and a larger trailing diameter. The pitch of the screw decreases between the leading and trailing ends thus causing the bone fragments in a fracture to be drawn together when the screw is installed across the fragments. The radially outer diameter of the threads increases between the leading and trailing ends thus causing each successive thread portion to cut into bone radially outwardly from the preceding thread portion thereby providing uncut bone in which the succeeding threads can gain purchase.

Abstract: An orthopedic interference screw for compression anchoring a bone graft in a bore formed in a bone mass. The interference screw includes a biocompatible body with a root. A screw thread is formed over substantially all of the root. The screw thread includes buttress structure on only one side of the screw thread so that forces applied to the screw thread from a side remote from the buttress structure will be buttressed by the buttress structure.

Abstract: A fastener is constructed having four thread zones constructed over the length of the fastener, from the head to the tip, namely a ridged cylindrical holding zone, a ridged cylindrical transition thread forming zone, a rectilobular tapered thread forming zone, and a rectilobular alignment zone. The pitch cross section of the thread varies in each zone.

Abstract: A self perforating (punching) and thread forming connecting element such as a screw having a screw shaft 2 and screw tip 6 which tapers to a pointed end 4 as well as a single or multiple thread 8 which extends at least partially along the screw shaft 2 and along the screw tip 6 to the pointed end 4. This screw tip 6 has an essentially polygonal cross section along at least a partial region of its axial length and the thread 8 is constructed as a radially raised portion which has a helical shape with an outer thread edge 8a which, when viewed in an axial projection, forms a spiral in the region of the screw tip 6 as the radius of the thread becomes smaller and in the region of the screw shaft 2, the outer thread edge 8a proceeds with a constant radius in the form of a circle.

Abstract: An orthopedic interference screw for compression anchoring a bone graft in a bore formed in a bone mass. The interference screw includes a biocompatible body with a root. A screw thread is formed over substantially all of the root. The screw thread includes buttress structure on only one side of the screw thread so that forces applied to the screw thread from a side remote from the buttress structure will be buttressed by the buttress structure.

Abstract: A retaining element to hold together a multipart preassembled screw connection or the like until the assembly can be further processed or assembled in a later step. The retaining element includes a ring section to be installed on a free part of the multipart connection unit so as to hold together the individual parts of that section, and a handle that extends in an outward radial direction from the ring section. Once the free part of a multipart connection unit is assembled to a mating connection unit, the ring section can be removed by applying a tensile force to the handle in an upward radial direction. The ring section may have a predetermined breaking point so that the ring section becomes severed when sufficient tensile force is applied, whereby the retaining element can be removed without difficulty.

Abstract: A drive screw comprises: a head portion; a shank; and a helical thread portion extending along almost all the length of the shank, wherein an outside diameter of the drive screw including the thread portion being formed so as to be reduced from a portion close to the head portion in at least three stages.

Abstract: A biangular countersink in a skin panel to be joined to an underlying support member includes a frustoconical base portion defining a large included angle and an extremely shallow outer portion cut at a very small acute included angle. Fasteners usable with the countersink have heads with frustoconical undersides matching the deeper base portion of the countersink and rounded heads sized to fit within the shallow, acutely angled outer portion of the countersink. The combination of fastener and biangular countersink reduces annular grooves or "halos" which typically are formed around conventional flush head fasteners.

Abstract: The present invention supplies a drilling screw which can fix a gypsum board to a thin steel plate by utilizing an impact-type air driven screw fastener and execution method for fixing efficiently the gypsum board to the thin steel plate. The drilling screw 11 comprising the parallel thread part 13 and the smaller diameter parallel thread part 15 which are connected through the taper thread part 14. The height of thread crest of the smaller diameter parallel thread part 15 is as small as about 0.1 mm. The taper bit 16 is formed at the fore end of the smaller diameter parallel thread part 15. When the drilling screw 11 is hammered into the gypsum board and the C-type steel plate structural material with the impact-type air driven screw fastener, the smaller diameter parallel thread part 15 is inserted through the steel plate. Since the smaller diameter parallel thread part 15 has so small diameter, the steel plate is seldom deformed.

Abstract: In a fastener having a head, which may have having torque-absorbing ribs, and a shank, which is unitary with the head and which has a primary thread formation and a secondary thread formation. The primary thread formation, which defines axially spaced threads along a generally cylindrical portion of the shank and along a tapered tip of the shank, has a generally uniform radial dimension along the generally cylindrical portion of the shank. The secondary thread formation, which defines axially spaced threads between some of the threads defined by the primary thread formation, originates at a region spaced axially from the distal end of the generally cylindrical portion of the shank, terminates at the head, and tapers outwardly from the region where it originates toward the head. The secondary thread formation at the region adjoining the head has a radial dimension less than the generally uniform radial dimension of the primary thread formation along the generally cylindrical portion of the shank.

Abstract: An osteosynthesis device having a bone screw, particularly a pedicle screw, a fork head that has a groove and a corrective pin seated in the groove of the fork head. A corrective pin is secured against twisting in that the bottom of the groove of the fork head is provided with a plurality of longitudinal slots lying parallel to one another.

Abstract: A threaded screw has a first segment adjacent the screw head (10) with nontapered sides for engaging metal automotive fastener clip nuts (30) and a second segment with tapered sides for engaging plastic bosses (24). The second segment is adjacent the first segment but distant from the screw head (10). A single set of threads (36) is used for both the metal clip nut (30) and the plastic boss (24). The threads (36) have a helical pitch angle (P) of about nine degrees and form a flank angle (.beta.) of about thirty degrees relative to a horizontal axis (20) of the screw. The screw taper matches the taper of the boss opening (22) to promote even stress distribution.

Abstract: A self-tapping screw fastener includes a shank having first and second ends and a head disposed at the second end of the shank. The shank has a tapered portion of a predetermined axial length adjacent the first end, and the tapered portion terminates at the first end in a substantially circular end surface having a first diameter. The shank also has a substantially cylindrical portion having a second diameter extending from the second end to the tapered portion. A thread extends helically along a circumferential outer surface of the shank from a location near the head substantially to the first end such that the thread at least partially covers the cylindrical and tapered portions of the shank. The ratio of the axial length of the tapered portion to the diameter of the end surface exceeds substantially 1.5, and the diameter of the end surface is less than but substantially equal to the diameter of the cylindrical portion of the shank.