Truss Rod - Construction and Action

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 correct 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. Luthiers 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 tightens it, counteracting the tension of the strings and straightening the neck or creating a backward bow. Turning the truss rod counter-clockwise loosens it, allowing string tension to act on the neck and creating a forward bow (higher string action).

Some guitars (notably Rickenbackers) 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.