After a
look at the chart of string tension, mass, and frequency, one will
realize that with that particular gauge of strings and string length,
the strings pull on the neck with 46.96 kilograms!! That's roughly 100
pounds!! The neck alone doesn't supply enough force to resist the
string tension, so engineers designed what is called a truss rod to
support this tension.
The truss rod runs through the neck of the guitar, and is bowed (as pictured above). If a set of thick strings are installed on a guitar, the strings will have a tendency to bow the guitar neck upward. To counter this force, a nut on the end of the truss rod is tightened, pulling the neck back down to equilibrium.
Above is another example of a truss rod being used. In the top picture, the strings are not parallel to the fretboard. On the bottom, the truss rod has been tightened, pulling the strings and neck back into proper place (note, the pictures are exaggerated and are used just as an example).
The truss rod runs through the neck of the guitar, and is bowed (as pictured above). If a set of thick strings are installed on a guitar, the strings will have a tendency to bow the guitar neck upward. To counter this force, a nut on the end of the truss rod is tightened, pulling the neck back down to equilibrium.
Above is another example of a truss rod being used. In the top picture, the strings are not parallel to the fretboard. On the bottom, the truss rod has been tightened, pulling the strings and neck back into proper place (note, the pictures are exaggerated and are used just as an example).