The Cook Trio

How To Lower Action On Acoustic Guitar?

Do you want to learn How To Lower Action On Acoustic Guitar?

Are you having a hard time playing your acoustic guitar? Or is it hard to deliver a full sound? You came to the right place!  

 You might be having difficulty because the action is too high. If this is the case, it leaves a significant gap between the strings and fretboard, which makes fretting the string more strenuous. That said, knowing how to lower action on acoustic guitar will come in handy in making playing more pleasant.  

 Here, we walk you through lowering the action on acoustic guitar, which involves three main steps: 

  • Fine-tuning the truss rod  
  • Modifying the action at the nut  
  • Modifying action at the bridge  

Tools for lowering the action on acoustic guitar

Tools for lowering the action on acoustic guitar

Before we delve into the guide, let’s first look at the tools you’ll need.  

 The first tool you’ll require is an accuracy-marked straight edge or a string action gauge. The latter is somewhat pricier than its counterpart but is worth every penny.  

 Next, it is necessary to have sandpaper, pencil, ruler, needle-nose pliers, and a file. The ruler and pencil will come in handy in marking out the section of the nut or saddle that needs to be removed.  

 You could also purchase a complete kit, as it comes with all the tools you’ll require for the task. It’s also a good idea to have some spare parts. In the event you remove too much of the nut or saddle, it would be best to have replacements. Similarly, you might want to replace it with a much better saddle or nut. 

 So, if you’re on the market for an upgrade, make sure it’s compatible with your acoustic guitar. Lastly are the shims. These will be useful when installing the components that can’t be fitted using glue.  

How to lower action on acoustic guitar

How to lower action on acoustic guitar

As promised, here is a multi-step guide on how to lower action on acoustic guitar: 

Step 1: Fine-tuning the truss rod

Assess the guitar neck's straightness

It would be best to assess the guitar neck’s straightness this way; you’ll see whether you need to modify the truss rod to reduce the action. Again, you’ll have to check if it is back-bowed or up-bowed.  

 If the neck is up-bowed, it will bend upwards marginally when holding the instrument flat. On the other hand, if the neck is back-bowed, it will slightly bend downward when held in the same position.  

 To inspect the straightness of the guitar’s neck, grip it at eye level, and check the neck. Alternatively, you could place it flat on a bench or table and inspect the neck.  

 Also, there’s another way to inspect the guitar neck’s straightness, though you’ll need someone to assist you. Press down a string on the 12th and 1st frets. Next, your friend will place a ruler against the strings you’ve pressed down. There is supposed to be about 0.01-inch between the fret and string.  

Find the truss rod.

This is a slender, steel rod within the guitar neck. Depending on your guitar’s design, you can locate the adjusting nut via the sound hole or at the peghead.  

 A modifiable truss rod is two-way or one-way, also called double-action or single-action. A single action rod will only straighten the guitar neck against upbow and tension. However, a double-action will correct both an up-bowed and back-bowed guitar neck. Again, you cannot modify a back-bowed neck with a one-way rod. On the other hand, if your guitar is new, there are high chances it sports a double-action since it became conventional in the 1980s.  

Modify the strings

This will be handy if the truss rod can only be accessed via the sound hole. This is because you’ll want to untighten the strings before trying to modify the truss rod. Additionally, placing a tool in the sound hole and twisting it will be easier. Then again, don’t completely remove all the strings.  

 Inspect the truss rod to determine the type of tool you’ll use. Generally, it will sport either a hex key or nut slot. If the truss rod can only be accessed via the sound hole, you’ll likely need a longer nut driver or Allen wrench to turn it. This way, you won’t be sticking your arm into the sound hole.  

 If your guitar’s truss rod can be accessed through the headstock, you won’t have to be stressed about the sound hole. You simply require removing the screws securing the cover of the truss rod. Avoid loosening the guitar strings when adjusting the rod from the headstock, as you’ll want to have them tuned ideally for the correct neck tension.  

Turn the screw on the truss rod.

With your nut driver or Allen wrench, slowly twist the truss rod screw. It might also be a good idea to lubricate the rod nut, particularly if your guitar is one of the older models or you’ve never turned the truss rod.  

 Keep in mind that turning right is tightening while turning left is loosening the truss rod screw. So, turn it right to fix an upbow and left to fix a back-bow. Mark the nut to know where you began when you’re finished. Don’t twist the screw over 1/8 per turn to avoid over-tightening.  

Tune your guitar again

Once you’ve made the first turn, you’ll have to tune your guitar once more so you can inspect the distance between the frets and strings to confirm if you’ve fixed the issue. This isn’t as simple as it sounds. The neck needs to have the right tension for it to show whether you properly straightened it or not.  

Repeat #4 & #5

If the first 1/8 turn hasn’t yet rectified the back-bow or upbow in the guitar neck, turn it again, then tune your guitar again and check. Remember the mark you made, and don’t turn the truss rod screw more than once since this can significantly harm your instrument.

Step 2: Modifying action at the nut

Modifying action at the nut

Have the necessary tools

The next step is to modify the action at the nut. So, if you’re done adjusting the truss rod, this is what you’ll do next. It would help if you had a set of nut files compatible with the string gauge on your guitar. Because every string features a different thickness, you’ll require six nut files. On the other hand, if you don’t have these nut files, you can purchase them at your local luthier shop or music store. You’ll also require a feeler gauge to measure each fret’s action

Tune the guitar

If it is not yet tuned, ensure you tune all the guitar strings before you begin assessing the action at the nut and making modifications.

Using a feeler gauge, gauge the action of the first fret.

Position the feeler gauge directly on the first fret to find out how much you must file down the nut to lower the guitar’s action. First, utilize a ruler to measure. It’s supposed to be 0.3 inches from the first fret’s string. If it’s more than that, keep looking at the gap using bigger feeler gauges till the guitar strings move.  

The gap between the frets and strings is the width of the biggest feeler that doesn’t cause string motion. Do this with all six strings.  

Untighten the sixth string

Cautiously loosen this string, only for it to get off the nut without spoiling it. Again, it should be loose enough to snap out, making it easy to thread it alongside the nut easily.  

File the nut

Have a proper nut file that can be used to file the sixth string, and get a small Masonite and plastic piece to shield the headstock. This way, you won’t file it as you file the nut.  

 Position the nut file in the notch and gradually file, motioning in the headstock’s direction. Make sure you file a small portion at a time since you can’t replace the material when you file it down. Also, it would be best to avoid filing it down excessively.  

 Once you’re finished, change the string, tune it, and gauge it once more to find out whether you have to refile; on the other hand, if you corrected the issue, proceed to the next step.  

Repeat #5 on the other strings individually

When you’re done filing the first guitar string, do this for the rest to lower the action on the guitar at the nut.  

Step 3: Lowering the action at the bridge

Locate the saddle & bridge

Lowering the action at the bridge

The saddle is an extensive, slender nut, typically made using synthetic material or bone, and it’s positioned at the bridge. That said, to lower action on acoustic guitar, you don’t need to modify the bridge at all; you simply need to tweak the saddle.  

 It plays the same role as the nut, regulating the guitar strings` height. Seeing as you already lowered the action at the nut, it’s now time to do it at the bridge; otherwise, the tune won’t be right. The strings are threaded via the bridge, and the saddle remains in position thanks to the bridge’s tension.  

 Typically, saddles are compensated or straight. Compensated saddles have a curved shape to compensate for the strings` tune. For this reason, if you’re looking to reduce action at the bridge, you must sand down the saddle’s bottom and not the top.  

Gauge the action of the guitar at the bridge

Using a ruler, measure the gap between the 12th fret and sixth string. Again, it would also help if you did this for the other strings. Most acoustic instruments take 2/32 inches of action from the initial string and 3/32 inches from the last string, so if your guitar is yielding more action than this, you might have to lower it, depending on your preferences. 

Untighten the strings

Since the strings` tension keeps the saddle in position, you will have to loosen the guitar strings. On the other hand, you can leave the strings on the tuners. Utilize the strings winder to untune the guitar till the strings are untightened. Do not remove all the guitar strings.  

Detach the three lower strings

It would be best to remove the last three strings when removing the saddle, though it’s unnecessary to get them all out. This will make the process more time-consuming and tedious. The last three strings will offer more than enough space to remove the saddle, as long as the rest of the strings are loose.  

You won’t have to detach the strings from the tuners unless they pass via the bridge. If this is not the case, the process will be more time-consuming since you’ll need to detach the guitar strings from the tuners to effectively remove the saddle.  

Detach the saddle from the bridge

Upon detaching the last three strings, you are supposed to have sufficient space to slide out the saddle from its position on the bridge. It would help if you were extremely careful as you do this. If it’s tightly secured, you might require pliers to hold and pull it gradually without spoiling the guitar.

Sand the saddle

When you successfully remove it, it’s now time to lower action. Keep the saddle even as you sand it down since an uneven saddle will spoil your guitar’s tone. There are several ways you can do this.  

 One of those techniques includes positioning double-stick sandpaper on a flat workbench or table. Take your ruler and find out how much of the saddle you wish to sand down. Mark it across using a pencil. Next, sand it down till you reach the place marked with a pencil.  

 Remember that if you overdo it, the strings will be extra-long. Also, taking out more than necessary might not be a good idea. Be careful and sand a portion at a time. You can always do it again if you feel like you didn’t sand enough. On the other hand, if you overdo it, it’s impossible to put back the lost section.

Put back the saddle & bridge.

The final step is to put back the saddle & bridge, lift the guitar strings and gradually slide the saddle back to position. Next, attach the three strings you had removed and tune your guitar again.  

 Gauge the action once more and play the instrument to see if you’ve lowered the action successfully. If the results are unsatisfactory, you can remove the saddle again and sand it down. However, the results will differ from one guitarist to another.  

What can cause high action on an acoustic guitar?

Now that we have walked you through how to lower action on acoustic guitar, let’s see what the main causes of high action on your instrument are: 

The nut is extremely high.

The nut is situated at the top end of the instrument. It is the top point of the guitar neck. That said, if it’s not correctly set or too high, it will surge the strings` height over the fretboard and spoil the instrument’s playability.  

The bridge saddle is extremely high.

This is one of the major culprits when it comes to your acoustic guitar’s action being too high. If your instrument’s action is too high, the bridge & saddle at the lower part of the strings are too long. Luckily, it‘s somewhat straightforward to fix it.  

The truss rod is not correctly adjusted.

Another source of high action on your acoustic guitar is that the truss rod is incorrectly set. The truss rod, as mentioned above, is the elongated pole, typically made of graphite or metal, positioned within the neck of the guitar. Its function is to hinder the formation of a bow on the neck of the guitar due to the strings` tension. So, if there is excessive neck relief, there will be too much action.  

 These are some of the manufacturing issues that could lead to high action on your guitar. All the same, there are environmental factors that can impact your acoustic guitar’s action like: 

Humidity & temperature

Like most wooden items, an acoustic guitar will be impacted by shifts in temperature and humidity. These effects are particularly evident when the shifts are sudden and sharp.  

 For instance, keeping your acoustic guitar in an air-conditioned room would be best if you reside in high-temperature areas. On the other hand, humidity makes the porous timber absorb the air’s moisture; therefore, it swells and expands.  

Shifts in string tension

The guitar strings put huge tensions on the neck of the guitar, which could result in bowing, and, afterward, high action. However, if the truss rod is properly set, a shift in the strings` gauge can lead to high action by increasing the neck relief.  

 For instance, if you’re used to playing light or extra light gauge, you might switch and fit in heavy gauge ones. The heavy strings will surge the tension, which might bow the guitar neck and increase your guitar’s action.  

Wear & tear

After playing your acoustic guitar for a long time, the frets might wear, increasing the gap between them and the strings. Since action is the height of the guitar strings above the top frets, it will surge the gap between them and the strings when the frets are worn out.

How about increasing guitar action?

Yes, you may use lemo

Increasing action on your guitar is rather effortless. The same steps as lowering action apply, particularly about settling the strings and modifying the neck in advance. When it comes to an electric guitar, the small loosened screws close to the bridge increase the strings` height.  

 At times, there are independent saddles for every string, though most of them have two screws on both sides of the bridge. Make minor adjustments, retune your instrument and play it.  

 For an acoustic guitar, it’s hard to raise the bridge & saddle other than putting shims underneath it. However, you can also purchase a new white saddle and replace your current one. When reducing action, you only have to resurface the bottom.  

 Shimming should be a last resort to your resurfaced saddle, though crafting and resurfacing the whole saddle will take time. This might be a good idea if you have plenty of time. Again, you can purchase a pre-cut saddle or consult a luthier on the best way to heighten the action. When you install the new saddle and find that the action is too high, you might need to lower it by working on the bottom of the saddle & bridge.  

n oil cleaners to wipe, rehydrate, and revitalize a rosewood guitar. But remember to only use lemon oil instead of lemon juice or sliced lemon fruit since it comes in the proper concentration for the wood.


Is it hard to lower action in an acoustic guitar?

No. While this is a three-stage process, it is not hard. Lower action means a huge gap between the frets and strings on your guitar.  

How do I lower the action on my guitar?

As pointed out, this is a three-stage process involving the following: 

  • Adjusting the truss rod 
  • Adjusting action on the nut 
  • Adjusting action at the bridge & saddle  

How do I determine whether my guitar's action is too high?

Here is how to know whether your guitar’s action is too high: 

  • You have difficulty fretting notes  
  • The tuning is off  

In conclusion

It’s not that hard to lower action on your acoustic guitar. It might be a long and meticulous process, but it’s not difficult. This guide will certainly come in handy for jazz players who like lower action.  

On the other hand, high action might not be the go-to option for these players. Hence, higher action is the most suitable option for heavy strummers and blues players, particularly if they have heavy gauge guitar strings.  

Most guitar players usually switch guitar strings, and sanding down seems like s difficult process. However, it is not hard, it’s just time-consuming, and you should be extremely cautious about ensuring that no harm comes to your instrument.  

Besides, in the end, this process is worth the effort and time since the result is a better playing instrument. A playable instrument entices you more to play; the more you play, the more you sharpen your skills and become a better guitarist. So, yes, this process is worth it.  

Didn’t know how to lower action on acoustic guitar? Now you know!  

Simon Mattav

I am the owner of The Cook Trio, a three-piece band that has been performing in the Chicago area for over 10 years. I have a passion for music – everything from guitar to songs. I graduated from the music University of Chicago! My passion is writing songs about my life experiences, feelings and emotions through different genres. My inspirations are some of today’s popular songwriters such as Ed Sheeran, Taylor Swift, Justin Timberlake, Selena Gomez among others.

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