This is one of those sticky adjustments on your guitar that is a pain to get just right. Check this out:
An Alternative Way To Adjust Your Guitar Nut
By: Andrew Preston
Most new guitars arrive from the factory with the nut just
barely playable. Older guitars may have the nut filed or worn
down so much that fret buzz cannot be eliminated by neck or
string height adjustment. If you have a new guitar, or you are
replacing the nut with a new one, here is an alternative method
to file and adjust the nut material to make your guitar play
like the professionals guitars play.
Before adjusting anything, make sure your guitar is strung up
correctly and that your neck is straight and not bowed or
warped. If your neck is bowed you first need to adjust the truss
rod. If your neck is warped it will require a more extensive
repair. For the lowest possible action or to avoid fret buzz all
across your finger board it may be necessary to have your frets
leveled and crowned first.
You will need a set of nut files (available from Stewart
MacDonald), and a good set of feeler gauges as well. Different
grades of sandpaper are very useful too.
Fret each string individually, starting with the High E, between
the second and third fret, use your feeler gauge to check the
amount of space between the bottom of the string and the first
fret. You should have approximately .005" of space between each
one, with the string barely touching the second fret. If this
measurement is close or dead on then move on to the next string
right up to the Low E string. You may want to record the gap on
a scrap piece of paper as you move across the fret board, to see
the nut slot's height in relation to the fret board as you do so.
For most players a string height (also known in guitar slang as
"action") of 3/64" of an inch is considered normal. Some players
choose a higher sting height such as 4/64" of an inch while
players which tend to have a light touch and want the fastest
action possible strive to lower the action as close as possible
to 2/64" which in many case's is very hard to setup and maintain
without fret buzzing somewhere on the finger board.
Of course, you can use the traditional method to set your string
height in relation to the nut, by using multiple feeler gauges
below the nut, and filing down to the factory depth and width.
However, I have found this method to provide a better and more
consistent feel while playing near the nut.
About the author:
Andrew Preston is a professional guitar session player and
dabbles in part time guitar repair. Your can see more
information at Guitar