Truss rods

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.