Tools
Assessment
We’ve set a firm foundation with proper neck assessment and adjustment, now it’s time to put some walls up and assess and adjust the nut as necessary. The goal here is to make sure that the action is set properly at the nut. If your strings are too low at the nut, then you’ll almost definitely be experiencing some fret buzz when you play your guitar. If the strings are too high, then you might be having some difficulty playing chords and scales close to the nut. In this tutorial you’ll learn how to determine if your strings are too high or too low and how to adjust them accordingly.
Assessment Process
1. Tune your guitar to standard pitch (E, A, D, G, B, E).
2. Lay your bass down on your work surface. Rest the neck on a brace if you have one.
3. Fret the low E string at the fourth fret.
4. Now, while still fretting the string, slide a .006 feeler gauge between the first fret of your bass and the bottom of the low E string.
5. What you’re looking for here is a slight drag. You should be able to slide the feeler gauge between the bottom of the string and the top of the first fret fairly easily, but not without a little drag. If it’s very difficult or impossible to slide the feeler gauge between the bottom of the string and the top of the first fret, then the string is too low and your nut needs to be shimmed up or replaced. If it’s too easy and there is almost no drag or no drag at all when you slide the feeler gauge, then your low E string is too high and you’ll want to file down the slot that it sits in.
6. Continue assessing each of the remaining strings (A, D, G, B, E).
Results/Diagnosis
Okay, so now that you’ve assessed the condition of your guitar’s nut and made a diagnosis it’s time to make some adjustments. Depending on the results of your assessment you may either need to file down some nut slots, raise your nut with a shim, do both, or do nothing.
Here are the possible outcomes of your assessment (paired with actions):
A. All or some strings sit too low.
Adjustment: First shim up the nut to raise the lowest strings or strings to the correct height, then file down the strings that are too high.
Raise Nut with Shim –>
B. All or some strings sit too high.
Adjustment: File down the strings that sit too high.
File Down Nut Slots –>
C. Some Strings sit too high while others sit too low.
Adjustment: In this case you’ll want to shim up the nut so that the strings that are sitting too low are all raised to at least proper height. Then you’ll want to use your nut files to file down the strings that are sitting to high.
Sand Nut Down –>
D. All strings sit at the desired height already.
Adjustment: Well aren’t you lucky. Move on to the next step in the setup.