Truss Rod

A metal bar or rod used to reinforce the neck of a guitar, bass, or other stringed instrument. The tension created by a set of guitar or bass strings tuned up to pitch is several hundred pounds, which over time takes it toll on the relatively small piece of wood making up a neck. The truss rod is inserted inside for reinforcement and to enable adjustments to the bow of the neck to be made. By turning a properly shaped truss rod at different angles inside the cavity of the neck one can force the neck to slightly different shapes, which obviously will change the playability and action of the overall instrument.