Bite Size Tips 002 - String Height @Nut

An Unbleached Bone Nut

There are many components on an acoustic guitar. Some which are very obvious and noticeable whereas some are inconspicuous but enduring. These passive components usually live through nearly the entire life span of any given guitar without breaking down. One may have lost count of the sets of strings changed as compared to replacement of those components. The guitar nut certainly fits the bill.

These are the basic functional aspects of a guitar nut,
1. Supports the guitar strings
2. Governs the string spacing
3. Enables guitar strings to vibrate with no obstruction
4. Ensures good playability
5. Increases the guitar aesthetic value

There are many aspects regarding guitar nuts. In this Bite-Size Tips edition, I will throw the limelight on point 4, i.e. ensures good playability. This actually means having the right string height at nut to stay away from string buzz and also gives comfort to its playability. The BIG question is; "How do we know what is the right height(s)?"

The first thing to learn is measuring the string height at nut. The following pictures have delineated the necessary steps and equipment you will need to accomplish this task.

1. Have you guitar tuned, place it in supine position. (ensure adequate cushion for protection)

Position your guitar properly

2. Start on any string; in this example, we shall start with the Lo E string
3. Press or fret the second fret of the Lo E string the regular way

4. Expect to see a narrow gap formed by the string and the crown of the first fret

5. Measure the gap using the right feeler gauge or a piece of cut regular office paper

6. Walah! The gap is measured!

Feeler gauge in use

Improvise with paper

Feeler Gauge (0.05mm to 0.5mm)

I shall stress that this method will give a relative measurement of the string height at nut. You should not expect to obtain the actual vertical height between the strings and the fingerboard regardless in mm or inches. If you insist of getting the vertical heights, you will find through experience that such measurements are hard to ascertain and they are barely useful as well.

In this article, I will address the measured space as "the gap". Most guitars get set up before they leave the factories or workshops. To eliminate any buzzing tendencies, the string heights at nut are usually generous. The gaps can vary from 0.40mm to 0.25mm. This can translate to vertical heights of 1.3mm to 1.6mm. Most accomplished players can handle such settings but not the beginners. While it may present as good training for beginners, it could be too tough for them. This is also the common cause for beginners in stopping to learn or play. Even the good players prefer good playability whenever possible.

Another common question; "Should the string height at nut be consistent for all strings?" It is probably a Yes/No answer. It has a lot to do with the player preferences, that is when the player is discerning of such adjustments. For those who are oblivious, it should be up to the guitar tech to recommend. Hopefully the recommendations are made with the guitar owner's interest as priority and not the convenience of the guitar tech. Below is a set of frequently used setting when I set up my clients' guitars, the measurements indicate separation of "the gap".

1st E - 0.10mm to 0.15mm
2nd B - 0.10mm to 0.15mm
3rd G - 0.10mm to 0.15mm
4th D - 0.15mm to 0.20mm
5th A - 0.15mm to 0.20mm
6th E - 0.20mm to 0.25mm

Some of you may wonder about the feeler gauge because not many people own one and let alone using it correctly. A regular office paper has thickness of 0.10 to 0.20mm. A common namecard is usually of 250 gsm weight and the thickness is about 0.25mm. If you don't have a feeler gauge, you can still make reasonable estimates of the "gap" by using paper or namecard.

One should bear in mind that wood built guitar will carry some degrees of inconsistencies especially in physical dimensions. Firstly wood is hygroscopic, i.e. wood absorbs moisture that leads to change in physical dimensions and wood is not perfect to begin with. I may vary "the gap" in accordance to the guitar's conditions and the owner's preferences.

Learning about the "gap"settings will naturally lead to the curiosity to make adjustments. The so called adjustment is actually deepening the nut slots by cutting them individually to attain the desired gap spacing. This task isn't impossible to undertake but it takes good practices to get the sweet spot. It is wise to practice on a subject before you embark to work on your guitar(s). Remember to sense the situation before you work on your guitar(s). If it is done blindly, the outcome can be tragically irreversible.

In closing, this article focuses on the means to determine if your guitar's string heights at nut are correctly set up or it is not. If you are able to successful determine the heights, it would be adequate. Making DIY attempts to adjust the string height at nut may not be advisable unless you are well practiced. Stay tuned for the next edition. Cheers.