Abstract: An improved body for a stringed instrument wherein the base of the neck slides into a body pocket and onto a flexible protrusion, both made of the body material. The flexible protrusion is drawn toward the pocket by a fastener thereby clamping the base of the neck to the instrument body. No metal parts attach to the base of the neck. The only metal parts involved are the threaded fastener which draws the flexible protrusion toward the pocket and the threaded insert in the flexible protrusion to which this fastener threads. Most of the clamping assembly is hidden inside the body and neck and is not visible when the body and neck are connected. The neck can be removed and replaced rapidly allowing instrument storage in a smaller space and allowing necks of varying scale lengths, fret configurations, or fretboard radius to be attached to the same instrument.

Abstract: An actuator system for a foldable stringed instrument (for example, a travel guitar). The actuator system serves two primary function: 1) to selectively retract and extend a ram rod used to unlock and lock a mid-neck hinge of the foldable stringed instrument.

Abstract: A string instrument has a neck attached to a body and extending outwardly therefrom. The body has a top plate joined to a bottom plate by a continuous rib forming an interior volume therebetween. A tailpiece is joined to the body. The tailpiece has tubular string bores. Each string bore has an entrance for receiving a string therein and an exit from which the string emerges and extends to the neck. At least one the exits has a cross-sectional shape in which a length of a major axis of the cross-sectional shape is greater than a length of a minor axis of the cross-sectional shape.

Abstract: A guitar includes fibers of lengths between 0.2 millimeters to 3 millimeters. The guitar further includes a guitar body, a headstock board, a soundboard, a fretboard, and a guitar bridge. Each of the guitar body, the headstock board, the soundboard, the fretboard, and the guitar bridge is a continuous and single structure. The disclosure also relates to a guitar and a method for manufacturing a guitar. The guitar is superior to the traditional acoustic guitars in terms of volume and mechanical performance, so that a service life of the guitar of the application can be increased by 2 to 3 times compared with traditional acoustic guitars and durable.

Abstract: A stringed instrument with sympathetic strings is provided that includes (in addition to the primary elements corresponding to standard instrument elements) sympathetic strings, one or more supplementary bridges, a supplementary string termination assembly, and a set of supplementary tuners. The sympathetic strings are stretched diagonally across the soundboard of the instrument, with one end of each string attached at a supplementary tuner and the other end attached at a supplementary string termination assembly. The sympathetic strings are spaced by the supplementary bridge(s) a sufficient distance from the soundboard to prevent interaction with it during vibration of the string during playing. The sympathetic strings are activated by sound vibrations created by the bowed primary strings, may additionally be activated by plucking or strumming, and may be manually muted.

Abstract: A playing aid for a stringed musical instrument comprised of an elastic member attached to a capo at one end and near the bridge at the other end. The elastic member has marks along its length indicating a certain number of frets between that mark and the capo. When the capo is attached in different locations along the neck, the elastic member stretches such that the number of frets between the capo and each marker is constant regardless of the capo position.

Abstract: A linear dovetail neck joint for a musical instrument having a neck, a body, and a fretboard. The linear dovetail neck joint relies on an internal dovetail with screw-adjustable tension while avoiding screws that go directly into the neck. The linear dovetail neck joint allows for extreme fret accessibility in the upper register of the fretboard (due to lack of heel on the neck), easier neck height adjustments, intonation correction, and unique front block configurations with hand relief—all without the need for adhesives. The linear dovetail neck joint permits a practical and aesthetically pleasing neck-to-body joint without the need for a heel on the neck. The result is a neck-to-body joint that is easily adjustable and serviceable.

Abstract: A system and method directed for an aluminum guitar frame or chassis contained or suspended inside a wooden acoustic guitar. The frame having a neck that provides a rigid skeletal frame for the guitar's neck that eliminates truss rods and need for adjustments, a suspended body frame that transfer energy from the strings to the sound board more efficiently while providing longer sustainability, and an adjustable bridge suspension system allowing for slight adjustments to the action of the strings while enhancing resonance of the sound board as well as reducing the amount of bracing required permitting the sound board to be thinner while enhancing the tone.

Abstract: The fretboard system provides a replaceable fretboard with customized placement of frets along the fretboard for a stringed instrument. A configuration of magnets on the neck of the stringed instrument secure the fretboard to the stringed instrument. The magnets attract a metallic underside, such as a sheet metal, of the detachable fretboard. A separating layer, including but not limited to a layer of wood or other composite material, separates the magnets from the sheet metal. At least one, preferably two or more, reinforcing members extend longitudinally along the neck of the stringed instrument to reinforce the neck.

Abstract: This invention comprises a novel mechanical system for adjusting downward and side-to-side pressure of strings on the bridge of stringed musical instruments. The system comprises a threaded female element, to which an instrument's tailgut is attached, and a threaded mounting bolt which freely spins in a socket joint, which is incorporated into a mounting bracket secured to the instrument's end block, thereby allowing the tailgut's position at the point of the saddle to be adjusted higher, lower, or side-to-side relative to the instrument's table. These features allow the instrument's volume, resonance, and playing response to be adjusted in small increments, without detuning the instrument, to allow musicians to adapt quickly to different environmental playing conditions and musical repertoire.

Abstract: A portable, modular guitar platform enables guitarists to explore the potential of their instrument by allowing a user to mix and match many different functional modules, including modules handmade by a luthier or other skilled artisan. The design accommodates many options for customization, may use off-the-shelf components, is highly portable, and can be made from a variety of materials. The arrangement enhances ease of maintenance, and reduces waste from defective components in manufacturing. While the preferred embodiment captures the standard functionality of an electric guitar in a collapsible and customizable package, the modular nature of the platform allows for the expansion of this functionality. Any number of other technologies, electronic or mechanical, may be incorporated to expand the functionality of the platform in practice, performance, and recording contexts.

Abstract: A portable guitar may include a neck provided with a string on its top surface, a head machine provided on one side of the neck and provided with a piezo device for amplifying a sound, a first and a second covers hinged on both sides of the neck by hinges and configured to open or close the neck by rotating about the hinges, a speaker installed in the inner space of the first cover, a detecting sensor installed on the first cover and configured to detect the closing or opening of the first cover and output a signal, and a controller for controlling for supplying a power to the piezo device and selectively switching a mode of the speaker into an amplifier mode or a speaker mode based upon the detected signal.

Abstract: In a method for improving the acoustic properties of spruce resonance wood for musical instruments at least one resonance wood blank is subjected to a treatment with Physisporinus vitreus under controlled, sterile conditions. The previously sterilized resonance wood blank is immersed into a liquid medium enriched with fungus myecelium and kept therein in the dark for an exposure time and finally sterilized, wherein during the exposure time a temperature of 18 to 26° C. and a relative humidity of approximately 60 to approximately 80% are maintained. Due to the fact that the liquid medium contains nanofibrillated cellulose (NFC) in an amount of 200 to 300 g per liter, a reproducible, uniform improvement of the acoustic properties of the resonance wood free from local defects is ensured.

Abstract: In effect, the Sculptured Neck Guitar comprises of purposefully structured fret shapes depicting a three-dimensional pyramid or top half of a circle into the entire guitar neck; face, sides, and the back uniformly. This structure of frets allows drastically improved string bending and also affords multiple variations of string and fret contact points to achieve multiple pitches sounded from one originating fret. Each fret position is enabled to produce a myriad of pitches opening multiple dimensions of pitch options on any or every fret. These structural modifications alone enable the musician a myriad of mobility and multiple new playing techniques adding new sound options within every fret when played while also maintaining the standard functionality and traditional sounds the guitar offers. To simplify, the invention affords a musician the ability to produce multiple notes with one finger on one fret by dramatically bending one string.

Abstract: Disclosed is a set of guitar accessories comprising a headstock plate adapted to be attached to a backside of the headstock of a guitar, and a bridge plate adapted to be placed inside a body of the guitar under the bridge, the headstock plate and the bridge plate being made of brass. Also disclosed are a version of the bridge plate located outside the guitar and a guitar comprising the headstock plate and bridge plate.

Abstract: A time clock signal processing system and method thereof, applicable to an environment of USB synchronous mode audio clock reconstruction, is disclosed. The clock signal processing method employed by the clock signal processing system first uses a first-stage phase-locked loops (PLL) to raise the frequency of the inputted USB start-of-frame (SOF) field, provides clock synchronization and outputs the second-stage PLL; then, the second-stage PLL reduces the timing jitter of the output of the first-stage PLL to below 20 ps.

Abstract: An adjustable instrument neck stiffener includes end plugs at each end of a hollow composite tube, which is preferably D-shaped, along with an adjusting bolt at one end. A first tension strip connects to one of the end plugs and a sliding element. A second strip, which is preferably made of carbon fiber, is located near the flat surface of the hollow composite tube, stiffening that side of the hollow composite tube. Tightening the adjusting bolt moves the sliding element towards the adjusting bolt end. The tension strip is also tightened, thus bowing the hollow composite tube and the instrument neck downward. This puts the hollow composite tube into compression and counteracts the tension created by the strings of the musical instrument.

Abstract: A modular apparatus and method of varying the playability and tonal characteristics of a stringed instrument such as an acoustic or electric guitar which is commonly provided with a body and a fretboard to the instrument's neck. The modular apparatus includes a longitudinal rail, accessible fasteners, intermediary spacer blocks and a plurality of adjustable and removable frets. The rail is configured to connect with the neck of the stringed instrument and to provide a base for the frets. The frets are configured to move as needed within apertures within the rail. The frets are also configured to receive and support the instrument's strings. The frets are selectively adjustable relative to the rail by the user to change the tonal and playability characteristics of the instrument.

Abstract: The present invention relates to a method and apparatus for adjustably associating two components such as two components of a stringed instrument. Such invention is particularly well suited for adjusting the action of a guitar and for allowing any one of a plurality of guitar necks to be quickly and easily associated with a guitar body. One embodiment of the invention includes associating a body-plate with a body interface defined by guitar body and configured for being mechanically associated with a neck-plate associated with a guitar neck wherein the body-plate in the neck-plate are movably associated with each other so that the action of the guitar maybe easily adjusted. Another embodiment of the invention utilizes a pintle block and pillow block configuration for providing the same function.

Abstract: A stringed musical instrument has a neck having a truss rod embedded therein and a tensioning mechanism to adjust the tension of the truss bar. A truss rod is typically seated at the peghead and extends within the neck to the body of the stringed instrument. A tension adjustment mechanism may incorporate a slide assembly having a ramp that engages with an actuating screw that is accessible from the front surface of the stringed instrument. Adjustment of the screw changes the tension of the truss bar. A tension adjustment mechanism may incorporate a cam that interfaces with an actuating screw, wherein the cam interfaces with the truss bar to adjust tension.

Abstract: A stringed musical instrument has a molded sound box and neck where the sound box is formed of between 20% to 60% carbon fibers, or other suitable fibers, and a polymeric resin or binder. The composition of materials utilized in the sound box is selected to increase stiffness and to control the tone of the instrument. The sound box includes an adjustable attachment mechanism having a pivot which is used to secure the neck to the sound box. The sound box includes a molded bracing structure having a plurality of braces and a molded bridge having a plurality of pockets which are used to enhance the structure for the sound box and provide a desired tone quality for the stringed instrument. The neck may include a molded neck insert and a molded fingerboard which are used to enhance the stiffness and stability of the neck.

Abstract: A musical instrument having a plurality of strings is provided, the strings extending along a longitudinal dimension. The instrument includes a concave fingerboard extending along the longitudinal dimension and spaced from the plurality of strings to define the action, wherein a portion of the concave fingerboard is below an adjacent surface of a body of the musical instrument.

Abstract: Stringed instrument, especially the guitar with flexible connection of the upper part of the heel of the neck below the fingerboard to the fixing block in the body of the instrument, whereby the lower free end of the heel of the neck is coupled to a fixing block in the body of a stringed instrument through the rod via a rectification element which dilates in reaction to atmospheric humidity changes.

Abstract: Embodiments are disclosed that relate a stringed instrument having a fingerboard support disposed between a fingerboard and a neck base. For example, one disclosed embodiment comprises a body, and a neck structure extending from the body, the neck structure comprising a neck base, a fingerboard support coupled with the neck base, and a fingerboard coupled with the fingerboard support, wherein the fingerboard support comprises a support surface configured to contact an underside of the fingerboard and a raised side that at least partially covers a lateral side of the fingerboard.

Abstract: A modular apparatus and method of varying the playability and tonal characteristics of a stringed instrument such as an acoustic or electric guitar which is commonly provided with a body and a fretboard to the instrument's neck. The modular apparatus includes a longitudinal rail, an accessible fasteners, intermediary spacer blocks and a plurality of adjustable and removable frets. The rail is configured to connect with the neck of the stringed instrument and to provide a base for the frets. The frets are configured to move as needed within apertures within the rail. The frets are also configured to receive and support the instrument's strings. The frets are selectively adjustable relative to the rail by the user to change the tonal and playability characteristics of the instrument.

Abstract: This is an improved pivot hinge for a collapsible stringed musical instrument providing for easy collapse and assembly of the instrument, such as the neck to the body of the instrument, collapsing into a sturdy, compact, and portable package, without altering the basic industry standard shapes and acoustics, and without twisting, or crimping the instrument's strings.

Abstract: A guitar neck joint routing system. The system includes a probe and router assembly comprising a gantry, a probe, and a plurality of routers, and a guitar neck and body nest comprising clamps and vacuum grips for holding a guitar neck and guitar body in place for taking measurements and routing a dovetail joint.

Abstract: A musical instrument having a plurality of strings is provided, the strings extending along a longitudinal dimension. The instrument includes a concave fingerboard extending along the longitudinal dimension and spaced from the plurality of strings to define the action, wherein a portion of the concave fingerboard is below an adjacent surface of a body of the musical instrument.

Abstract: Conventional stringed musical instrument fingerboards are constructed with a constant longitudinal slope, relative to the string, along the fingerboard's length direction. Fingerboards with variations in their slope along their length direction could improve playability by shortening the string-to-fingerboard distances. A variable slope fingerboard is suggested to improve playability at locations close to the bridge.

Abstract: Stringed instrument having an elongated neck member optionally including a fingerboard, with a plurality of frets fixedly positioned at predetermined spaced locations along the neck. The frets include a tang and a mushroom shaped crown, each positioned and secured in a corresponding fret slot formed in the neck. The neck member includes a carbon fiber based support member that can be T-shaped. In its method aspects, the neck can be straight and of neutral strain or a desired backbow/underbow or curvature in the elongated neck member is created, such as by introducing a carbon fiber T-bar support member in the neck member in a “neutral” state while clamping the neck member in an underbow shape, or forming underbow directly into the finished neck in which a carbon fiber T-bar is already present, and then introducing crown bar style frets to wedge the neck back to an optimum playable shape.

Abstract: A truss rod for use with a neck body of a musical instrument. The truss rod includes a first rod connected to a second rod. An adjustment member is connected to the first rod and configured to exert a longitudinally directed force on the first rod that causes the first rod to move longitudinally with respect to the second rod. This movement exerts a laterally directed force on the second rod that causes the second rod to exert a laterally directed force on the neck body to thereby change the curvature of the neck body. The adjustment member may threadedly engage the first rod and exert the longitudinally directed force on the first rod by threading into or out of the first rod. The adjustment member may also threadedly engage the second rod. Different thread pitches may be used to threadedly engage the adjustment member with the first and second rods.

Abstract: An adjustable musical instrument neck stiffener includes a beam fabricated by embedding uni-directional material only at the upper portion of the beam, and constrained by braid or bias weave material. In a preferred embodiment, the uni-directional layers are preferably made from carbon fiber tow, cloth, or pultruded carbon fiber and the braid or bias weave material is made of carbon fibers. To reduce weight, the middle section of the beam is preferably hollow. A threaded rod and threaded sleeve provide a way to adjust the neck stiffener beam curvature so that it is straight while under string tension.

Abstract: A stringed musical instrument has a molded sound box and neck where the sound box is formed of between 20% to 60% carbon fibers, or other suitable fibers, and a polymeric resin or binder. The composition of materials utilized in the sound box is selected to increase stiffness and to control the tone of the instrument. The sound box includes an adjustable attachment mechanism having a pivot which is used to secure the neck to the sound box. The sound box includes a molded bracing structure having a plurality of braces and a molded bridge having a plurality of pockets which are used to enhance the structure for the sound box and provide a desired tone quality for the stringed instrument. The neck may include a molded neck insert and a molded fingerboard which are used to enhance the stiffness and stability of the neck.

Abstract: Slide guitar for providing various improvements and advantages including instant accurate string height adjustments simultaneously at the nut and bridge. The slide guitar has a marked adjustment knob adjacent a graduated scale under the headstock to visually determine with repeated mathematical accuracy the exact distance between the bottom of the strings and the top of the first fret as a point of reference. The improved string musical instrument includes a leveling head embedded into portions of the headstock and neck wherein the leveling head contains a slide selector having a sloped surface for contacting the nut combined with a dual bridge for instantly changing the instrument's string height and bridge type. The slide guitar instantly changes from a conventional type guitar to a steel type guitar creating an improved variable string action slide guitar.

Abstract: A truss rod adjustment device includes a truss rod gear assembly, an adjustment gear assembly and a base. The truss rod gear assembly includes an end shaped to fit in and engage a truss rod wrench socket attached to a neck of a guitar. The adjustment gear assembly includes an adjustment socket shaped to receive and engage a wrench. The base attaches to the neck of the guitar and holds the truss rod gear assembly in position to engage the truss rod wrench socket. The base also holds the adjustment gear assembly in position both to engage the truss rod assembly gear assembly and to position the adjustment socket to be accessible through a hole in a back of the guitar.

Abstract: A neck construction for a stringed instrument such as a guitar has an asymmetric, preferably trapezoidal, profile of the neck. The asymmetry is opposite at the distal end, depicted in FIG. 9, and proximal end, depicted in FIG. 10. As the musician plays the instrument, the hand will move between the proximal and distal ends of the neck, using the thumb and palm as a support to press the fingers against the front portion of the neck. By changing the angles of the surfaces denoted as (15) and (19), and (16) and (20) from the proximal to the distal end, the musician's wrist is encouraged and guided to move in a comfortable and relaxed angle throughout the playing range of the instrument, while the musician's muscles and tendons are supported, thereby reducing the risk for the musician to develop repetitive strain injuries and allowing the musician to play better.

Abstract: Stringed instrument having an elongated neck member optionally including a fingerboard, with a plurality of frets fixedly positioned at predetermined spaced locations along the neck. The frets include a tang and a mushroom shaped crown, each positioned and secured in a corresponding fret slot formed in the neck. The neck member includes a carbon fiber based support member that can be T-shaped. In its method aspects, the neck can be straight and of neutral strain or a desired backbow/underbow or curvature in the elongated neck member is created, such as by introducing a carbon fiber T-bar support member in the neck member in a “neutral” state while clamping the neck member in an underbow shape, or forming underbow directly into the finished neck in which a carbon fiber T-bar is already present, and then introducing crown bar style frets to wedge the neck back to an optimum playable shape.

Abstract: The present invention is directed a retractable stringed musical instrument, and more particularly, to a stringed musical instrument having a tailpiece, a body coupled to the tailpiece, a neck coupled to the body and a fingerboard coupled to the neck. The fingerboard and the neck adjustably extendable and retractable relative to the tailpiece. The retractable stringed instrument further comprises a bridge coupled to the body where the bridge vertically movable upon retraction of the fingerboard and the neck to enable the fingerboard to move over the bridge.

Abstract: A stringed instrument can be manufactured with a neck that contains a back-side soft surface layer and optionally also a front-side soft surface layer, whereby the soft surface layers can increase comfort and enjoyment, and prevent, reduce or alleviate injury during play of the instrument. Alternatively, a standard stringed instrument can be retrofitted with an installable soft surface component, which can be fitted on top of the surface of the back-side of the neck of the standard stringed instrument. Further disclosed is a method of using a neck mounted soft surface layer with a standard stringed instrument.

Abstract: The present invention extends to practice devices for practicing to play stringed instruments. More specifically, the present invention relates to a practice device that may assist a user in learning how to properly finger and play a stringed musical instrument. A user can hold an elongate handle and place one or more of his or her fingers on strings to practice fingerings that are used to play chords/notes. Real instrument strings can be used, helping to strengthen a user's fingertips and get the fingertips accustomed to holding/pinching the instrument strings. Further, the stringed instrument practice device can be portable and sized to fit within the user's hand. Accordingly, a user can realize advantages of the invention and utilize practice methods while the user is “on the go,” riding on a bus, watching television, waiting in line, etc.

Abstract: A training aid for playing a stringed instrument of the type having a neck and a fingerboard for assisting an instrument player in the proper placement of the thumb on the back of the instrument neck while playing the instrument, said training aid comprising: (a) a solid piece positioned on the back of the neck of the instrument against which said instrument player's thumb will be positioned; (b) an attachment to the solid piece, wherein said attachment enables said solid piece to be added to the back of the instrument's neck or removed from the back of the instrument's neck. The instrument may be a guitar.

Abstract: A musical instrument neck stiffener includes a beam fabricated by embedding uni-directional material only at the upper and lower portions of the beam, and constrained by braid or bias weave material. In a preferred embodiment, the uni-directional layers are preferably made from carbon fiber tow, cloth, or pultruded carbon fiber and the braid or bias weave material is made of carbon fibers. To reduce weight, the middle section of the beam is preferably hollow. An angle neck stiffener includes a hollow tube connected to a cradle, which is bonded within an instrument neck. The angle neck stiffener bridges the connection between the instrument neck and a preferably D-shaped neck stiffener.

Abstract: A stringed musical instrument comprises a neck, a body and a neck joint. The neck has a heel comprising at least a wedge. Correspondingly, the body has a heel slot at a neck joint location along an upper bout of the body. The heel slot is complementary to the heel of the neck and includes a shaped pocket that corresponds with the wedge of the neck. The neck is attached to the body such that the wedge engages the shaped pocket of the heel slot and the neck is fixed to the body, e.g., using an adhesive.

Abstract: A stringed instrument having a body assembly including a fingertip locating feature is disclosed together with methods of manufacturing the instrument. The instrument body is characterized by a bottom surface, a top surface, and a bridge mounting location at the top surface adjacent to a heel end of the body. A neck connection interface end is located opposite the heel end, a string sounding area defined between the interface end and the bridge mounting location. The body assembly has at least a first underpitched feature extending a selected distance between the ends adjacent to the string sounding area.

Abstract: An attachment mechanism for selective attachment of a stringed instrument neck to a stringed instrument body includes a recess formed in the body with a first part of a latch mechanism. The neck includes a capture block at a forward end thereof adapted to fit snugly within the recess of the body and having a second part of the latch mechanism. With the neck seated in the recess of the body, the neck may be pressed down until the first part of the lock mechanism engages the second part of the lock mechanism to lock the neck into the body. A threaded bolt traversing the body may be included to engage a threaded aperture formed in the neck to further secure the neck to the body. A removable bridge and carrying case may be further included.

Abstract: A guitar neck joint routing system. The system includes a probe and router assembly comprising a gantry, a probe, and a plurality of routers, and a guitar neck and body nest comprising clamps and vacuum grips for holding a guitar neck and guitar body in place for taking measurements and routing a dovetail joint.

Abstract: This system provides an acoustic string instrument that allows a musician to carefully adjust the height of the fingerboard relative to the body of the instrument by means of two slidable machined inserts that are inserted into the neck and body of the instrument. The inserts are adjusted by a hex wrench inserted into the back of the body of the instruments. The neck can also be completely removed by disengaging the inserts for transport.

Abstract: A stringed instrument having a body assembly including a fingertip locating feature is disclosed together with methods of manufacturing the instrument. The instrument body is characterized by a bottom surface, a top surface, and a bridge mounting location at the top surface adjacent to a heel end of the body. A neck connection interface end is located opposite the heel end, a string sounding area defined between the interface end and the bridge mounting location. The body assembly has at least a first underpitched feature extending a selected distance between the ends adjacent to the string sounding area.

Abstract: A truss rod adjustment device includes a truss rod gear assembly, an adjustment gear assembly and a base. The truss rod gear assembly includes an end shaped to fit in and engage a truss rod wrench socket attached to a neck of a guitar. The adjustment gear assembly includes an adjustment socket shaped to receive and engage a wrench. The base attaches to the neck of the guitar and holds the truss rod gear assembly in position to engage the truss rod wrench socket. The base also holds the adjustment gear assembly in position both to engage the truss rod assembly gear assembly and to position the adjustment socket to be accessible through a hole in a back of the guitar.

Abstract: A truss rod for use with a neck body of a musical instrument. The truss rod includes a first rod connected to a second rod. An adjustment member is connected to the first rod and configured to exert a longitudinally directed force on the first rod that causes the first rod to move longitudinally with respect to the second rod. This movement exerts a laterally directed force on the second rod that causes the second rod to exert a laterally directed force on the neck body to thereby change the curvature of the neck body. The adjustment member may threadedly engage the first rod and exert the longitudinally directed force on the first rod by threading into or out of the first rod. The adjustment member may also threadedly engage the second rod. Different thread pitches may be used to threadedly engage the adjustment member with the first and second rods.