5 Ways To Adjust Acoustic Guitar Action

Learning to play your acoustic guitar effortlessly can take some time. One of those aspects of playing is known as the ‘action’ and has several facets.

5 Ways To Adjust Acoustic Guitar Action

From how easy the acoustic guitar is to fret to the simple height of those guitar strings can enhance how easy the action truly is.

You should want to get to know your acoustic guitar and that means finding the ways you can adjust the action.

Ensuring that you have a comfortable feeling with your guitar playing can allow you to focus on other parts of your performance.

Perhaps you have seen lowered or adjusted parts of the guitar, even a playing card in a specific position or some evidence of sanding. All these slight alterations can help the action. 

In this guide, we will look at five different ways to adjust the acoustic guitar action.

Why The Action Is Important To Your Playing

Any acoustic guitar player will have their favorite action yet how they came to arrive at it could be through different ways, even simple trial, and error.

A harder player may prefer the action a little higher to prevent the strings from buzzing whereas a lighter, more delicate player will prefer it lower so the fretting is easier. 

Three parts on an acoustic guitar control the action which includes the bridge saddle, the nut, and the truss rod.

Do not forget the specific places on an acoustic guitar either which are at the first, fifth, and 12th frets.

Learning where you can adjust the action is important to know how to get the action to just how you want it on any acoustic guitar. 

The Places To Adjust The Action

There are three places on an acoustic guitar where you can adjust the action but five different ways in total to do it.

Some are easier than others so, just how you would practice learning new chords, practice the ways you can adjust the action so you can get it just right. 

Lowering The Action – Sanding The Nut

5 Ways To Adjust Acoustic Guitar Action

If your acoustic guitar is proving difficult to play then it may be because the action is positioned too high.

With a large distance between the fretboard and the strings, it can prove difficult to fret. One method of lowering the action is by sanding the nut.

Be careful with this method as once you have sanded too much you may need to replace it altogether.

Check the channel that lies between your acoustic guitar’s headstock and fretboard and you should see the nut.

There will be strings that pass over it and it effectively offers a fixed point for the fretboard and scale length to begin at. 

Just use some sandpaper to sand the underside of the nut which should lower its height.

That sounds straightforward but you will need to remove the strings first then reattach them several times until you get the nut just the right height.

Also, sanding the nut too much can cause it to be too low which will inadvertently make the fretboard buzz and that can get truly annoying. 

Raising/Lowering The Action – Altering The Truss Rod

5 Ways To Adjust Acoustic Guitar Action

The truss rod can be crucial to your action and simply raising or lowering it can have an impact. This is the metal bar that lies inside the guitar neck and goes all the way down the fretboard.

The truss rod is fixed at two separate points under the fretboard, you can find one close to the 14th fret and the other at the start of the nut. 

Getting to the truss rod can be from the top of the neck, just where the fretboard meets the headstock, or from inside the sound hole.

Tension is used to put a forward or backward-bow into the guitar’s fretboard and you would need an Allen wrench to create either one.

This is simply done by turning it clockwise or counterclockwise around the center of the neck just by the fifth fret.

A higher action in the center of your acoustic guitar can be achieved by turning that Allen wrench counter-clockwise.

If you want a lower action, turn it clockwise which sounds simple enough. Bear in mind, the action will be altered most around that fifth fret so the results will be less felt around the first and 12th frets. 

Be careful not to turn the truss rod excessively as you may experience fretboard buzz by making the plane uneven and the strings still have to be placed over it. 

That fretboard buzz may not be down to the acoustic guitar but it may be down to how hard you fret. If your playing style is not at fault then check that the strings are not too low.

You can also place the acoustic guitar down to check that the heights of each fret are level.

Remember that raising the action should decrease any perceptible buzz while lowering it is likely to increase that buzz.   

Raising The Action – Shimming The Nut

5 Ways To Adjust Acoustic Guitar Action

Another way to raise the action is by shimming the nut. By shimming the nut, you can affect the action in those first five frets but it will have little effect on the ones further up.

You can still do that but you would need to alter the bridge saddle, which we will look at next.

This is the spot where you can insert part of a playing card to act as a makeshift shim below the nut.

Only a thin strip of a playing card is needed and it should match the size of the nut slot but you will need to then de-tune your guitar first and then remove that nut.

You can also use a pencil placed under the strings to effectively hold them in place while you do this. 

The act of removing the nut may be difficult, especially if it is fixed in place with glue or lacquer.

If you are worried you may be committing irreparable damage to your acoustic guitar then a local guitar shop should be able to help you out.

Once the nut has been removed, the playing card can be put into that channel then you can replace the nut and re-tune the guitar. Give it a quick strum and the action should be improved.

Lowering The Action – Sanding The Bridge Saddle

5 Ways To Adjust Acoustic Guitar Action

Ah yes, the bridge saddle can also be sanded to effectively lower the action though with any sanding you should be careful not to go too far.

The height should be a certain height or you do run the risk of creating a buzz whenever you strum the strings.

The bridge saddle is that solid piece of plastic or even bone that is sat in the guitar’s bridge. This is then mounted along the belly of the guitar to hold the final endpoint of your strings.

When you do alter the height of the bridge saddle, you can expect more of a change at the position of the 12th fret rather than the first.

The bridge saddle effectively does the same thing as the nut in that it controls the height of the guitar strings.

Once you have lowered the action by the nut, you should lower it at the bridge to ensure level strings and an even tone. 

First, you want to measure the guitar’s action right at the bridge with a ruler which will measure the distance from the sixth string and the 12th fret.

Make a note of that measurement then repeat it for the first string, again at the 12th fret. 

A lot of acoustic guitars will take around 2/32 of an inch (1.5mm) of action for that first string then a little more at 3/32 of an inch (2.3mm) by the sixth string.

Any more than that should be lowered and you can do that by simple sanding.

Start by loosening each string to get access to the bridge saddle. As the string’s tension holds that bridge saddle in situ, you will need to loosen the strings first.

You can use your string winder if you want to de-tune your acoustic guitar and it should make the strings nice and loose so you do not have to remove them.

If you did want to get the bridge saddle out then you will have to take out the lower three strings.

Not all of them, just the lower three strings which should give you ample room if the remaining strings are loose.

You should be able to slide the bridge saddle out of its slot but do so carefully as you may need pliers if it is in good and tight.

Once out, you can use your sandpaper to lower the action at the bridge but ensure it is an even sanding. 

Do some preparation first to see how much you should sand it by and to ensure it is even. Use a level table or a workbench and use a ruler with a pencil to make each measurement.

Do not sand too much as then the strings would be excessively long. Check it after some sanding as you can always repeat the process though if you go too far there will be no turning back.

With your bridge saddle just sanded enough, you can replace it by lifting those remaining strings. Pop the bridge saddle back in its slot then replace those other three strings and re-tune your guitar.

Like every other method, perform a quick strum of your guitar and check that the action suits you.   

Raising The Action – Shimming The Bridge Saddle

5 Ways To Adjust Acoustic Guitar Action

As well as shimming the nut, you can also shim the bridge saddle. This is the ideal method if you wanted to change the action closer to the top of your fretboard.

Again, you will need a thin strip of a playing card that matches the slot for your bridge saddle. Ensure it is the same length and width then make it slightly smaller so it can lie flat at the bottom. 

With an ideal fit, the piece of a playing card should be flat in the channel without any bumps and you should not have to squeeze it in.

Place the bridge saddle on top again then restring your guitar. Whatever you do, do not use glue as the bridge saddle may need to be altered again and you do not want to break it off. 

However, that does mean that you can use this method alongside another. For instance, if you sand off too much of the bridge saddle or not, you can add a shim to balance it out.

This only proves effective so far as with too many shims the saddle can begin rocking which will hurt your guitar playing.

Simply stick to one or two shims as any more and you could have an unstable nut or bridge saddle. 

Final Thoughts

Adjusting the action of your acoustic guitar can be a fundamental step to ensure that you can play it properly.

This can be as simple as sanding the nut or bridge saddle though do not sand too much as it cannot be retrieved.

You can also shim both parts to balance it out though too many can mean too many moving parts of your acoustic guitar which can prove distracting.

Then there is the truss rod which can be raised or lowered and each method can bring you closer to your acoustic guitar and closer to your ideal playing.

Frequently Asked Questions

How Do I Get A Low Action Without Fret Buzz?

You can sand both the nut and the bridge saddle though this may prove challenging and there are other ways.

You could improve your fretting technique or opt for fret dressing. There is also the neck relief which can be adjusted or you can simply buy a higher gauge string for more tension. 

What Can Cause Fret Buzz On An Acoustic Guitar?

That buzzing sound can get so annoying and it occurs when the guitar strings vibrate against one or a few frets. This can be in the open position or just with specific strings and specific frets.

The humidity and temperature can also be a common cause of fret buzz. There could also be an issue with the wiring of your guitar and you can always take it to a guitar shop to check.

Howard Matthews