The Playing Action
For beginners, it is important not to have strings that are too high off the
fingerboard, because this increases the necessary pressure for the left-hand fingertips
to hold down a clear note or chord.
The strings are supported by detachable bones at the nut and bridge (see illustration).
The nut bone, which is slightly grooved to provide a guide for each string, sets
the height above the fingerboard at that end. If the strings are too low they will
buzz against the frets. If they are too high, the guitar becomes hard to play, which
can completely discourage you from continuing.
If the setting is too high, the nut bone needs to be removed and filed down from
the underside. If it is too low, a sliver of cardboard or similar material may be
inserted underneath, but this should be a temporary solution until a new bone of
the right height can be obtained. On a classical guitar the height of the strings
at the first fret will be about 1/16 in (1.5 mm).
At the bridge end, a similar adjustment can be made to the bridge bone to produce
a height at the twelfth fret of approximately 3/16 in (5 mm). The reason the measurements
are approximate is that the exact amount depends on the height of the frets and
the total string length, both of which vary from maker to maker.
Note that these measurements are for the nylon string guitar. The metal strings
of the acoustic guitar are set lower due to the greater tension, and for the sake
of the left hand, steel strings need to be as low as is practical, consistent with