Truss rod 3669380 223149557 2008-07-02T19:59:25Z KazKylheku 1015710 /* Application */ Add link for intonation. A '''truss rod''' is a [[guitar]] part used to stabilize and adjust the lengthwise foward curvature (also called ''relief''), of the neck. Usually it is a [[steel]] rod that runs inside the neck and has a bolt that can be used to adjust its tension. The first truss rod patent was applied for by Thaddeus McHugh, an employee of the [[Gibson Guitar Corporation|Gibson]] company, in 1921<ref>{{US patent reference |number = 1446758 |title = Neck for musical instruments |inventor = Thaddeus McHugh |y = 1923 |m = 02 |d = 27 }} — first patent known on truss rod.</ref>, although the idea of "truss rod" can be encountered patents as early as 1908<ref>{{US patent reference |number = 964660 |title = Stringed musical instrument |inventor = George D. Laurian |y = 1910 |m = 07 |d = 19 }} — a patent on instrument that is "designed like [[harp guitar]]", but it mentions "truss rod" concept "to prevent a head springing under the strain of strings".</ref>. == Application == [[Image:Guitar neck.svg|thumb|400px|Cross-section of an electric guitar neck showing the position of the truss rod]] When the truss rod is loosened (i.e. moved towards the guitar's body), it allows the neck to bend slightly in response to the tension of the strings. Similarly, when tightened (i.e. moved towards the guitar's [[headstock]]) the truss rod straightens the neck by resisting the tension of the strings. It is desireable for a guitar neck to have a slight relief in order that reasonably low action is achieved in the high fretboard positions, while at the same time, the strings ring clearly in the low positions. Improved action in the high fret positions also allows for more accurate [[Intonation (music)|intonation]], to be achieved with less compensation at the bridge. Truss rods are required for instruments with steel (high tension) strings. Without a truss rod, the guitar's wooden neck would gradually warp (i.e. bend) beyond repair due to applied high tension. Such devices are not normally needed on instruments with lower tension strings, such as the [[classical guitar]] which uses [[nylon]] (previously [[catgut]]) strings. == Construction and action == Truss rods are frequently made out of [[steel]], though [[graphite]] and other materials are sometimes used. The truss rod can be adjusted to compensate for expansion or contraction in the neck wood due to changes in humidity or temperature, or to compensate for changes in the tension of the strings (the thicker the guitar string, the higher its tension when tuned to concert pitch). Usually, the truss rod of a brand-new instrument is adjusted by the manufacturer before sale. Adjusting the truss rod is not recommended for a novice, as guitar necks can be easily damaged beyond repair in the process. [[Luthier]]s or more experienced players can adjust it when necessary (e.g. if strings of a very different tension are to be used). Turning the truss rod clockwise will tighten it, counteracting the tension of the strings and straightening the neck or creating a backward bow. Turning the truss rod counter-clockwise will loosen it, allowing string tension to act on the neck and creating a forward bow (higher string action). Some guitars (notably [[Rickenbacker]]s) come with dual truss rods that are more stable and not affected by seasonal climate changes, they are also more difficult to adjust and should be serviced by a professional. Though uncommon there are also left-handed truss rods that need to be rotated in the opposite direction of a normal truss rod. == Location and adjustment == [[Image:Truss_rod_screw.jpg|thumb|Truss rod adjustment bolt visible from the side of headstock]] The truss rod tension is usually controlled using an adjustment bolt (a hex nut or allen-key). Depending on the model of guitar, this bolt can be located: * On older [[Fender Musical Instruments Corporation|Fender]]-style electric guitars with [[bolt-on neck]]s (and vintage re-issues) &mdash; on the heel of the neck. Adjustment of such truss rods can be done by a Phillips screwdriver and requires prior removal of the guitar's [[pickguard]] or neck. * On newer Fender-style electric guitars &mdash; behind the nut, uncovered and can usually be adjusted by a 1/8" (3 mm) [[Allen wrench]]. * On [[set-in neck|set-neck]] electrics &mdash; under a cover-plate behind the nut. [[Gibson Guitar Corporation|Gibson]] & [[Epiphone Guitars|Epiphone]] guitars have their truss rod bolt covered with a signature bell-shaped plate. Most Gibson electrics have a 5/16” (8 mm) or a 1/4" (6 mm) hex adjustable truss rod nut that can be adjusted with a hex box spanner [[wrench]]. * On [[Steel-string guitar|acoustic guitar]]s &mdash; inside the guitar body, accessible through the [[sound hole]], or on the headstock. Martins use a 3/16" (5 mm) [[Allen wrench]] and Gibson uses the same as for the Gibson electrics above. * Counterclockwise adjustment will decrease the truss rod tension (correct an overbow) and clockwise adjustment will increase the truss rod tension (correct an underbow). Installing a truss rod in a newly constructed guitar requires woodworking capabilities. Special tools are required including a router with a variety of bits and ability to work with metals. Completed truss rods can be purchased through suppliers or manufactured according to specifications given in literature. Be sure of your measurements when constructing a guitar as they all play into the guitars full scale and playability. Consult a professional luthier or literature before constructing your own guitar. == See also == *[[List of guitar-related topics]] <!-- Set one the neck clamping staff under (course)Spannung, then the curvature of the staff that the griffbrett is pressed upward in the center and the neck, from the player regards itself, causes quasi to the rear bends. However the course of the strings works against this tendency . With optimally adjusted neck this will bend itself even easily forward, since the strings have the largest amplitude when playing in the center. If the tension of the staff is thus too large, the neck is whole straight or bends themselves even to the rear. The strings affect then when fastening fast the griffbrett (with federationless neck) or the federations and scheppern. If the clamping staff is however too weakly adjusted, the neck bends itself too far forward. Then the problem arises that the taping bar of the instrument decreases by the high string situation (distance it strings to the griffbrett) strongly. Precise play and good Intonation are then more with difficulty possible. --> == References == <references/> [[Category:Guitar parts and accessories]] [[de:Halsspannstab]] [[es:Alma (instrumento)]] [[fr:Barre de réglage]] [[it:Truss rod]]