Adjusting the action on an acoustic guitar is a critical but often overlooked maintenance task. It can significantly improve playability, enhance tone, and prevent issues like fret buzzing or string height issues. This guide will take you through the steps of how to adjust the action on your acoustic guitar so that it plays and sounds its best.
Before you begin, you’ll need a few basic tools: a hex key (often provided with the guitar), a ruler or straightedge, and a capo. First, measure the current action at the 12th fret. The ideal action height is around 2.5mm for the low E string and 2mm for the high e string. Adjust the truss rod at the headstock using the hex key. Turning clockwise will increase the neck’s relief (lowering the action), while turning counterclockwise will decrease the relief (raising the action).
Once you’ve set the neck relief, adjust the saddle height at the bridge. This directly affects the height of the strings above the fretboard. Using a hex key or small screwdriver, carefully raise or lower the individual saddle inserts until you achieve the desired action height. Remember to check the action at multiple frets and make fine adjustments as needed. Proper action adjustment not only ensures optimal string height but also contributes to the overall setup and playability of your acoustic guitar, allowing you to enjoy a more comfortable and enjoyable playing experience.
Identifying and Measuring String Height
Measuring String Height
Precisely measuring string height is crucial for optimal guitar playability and tone. Utilize a string height gauge, a specialized tool designed to measure the distance between the strings and fretboard at specific points.
Steps to Measure String Height
- Gauge Selection: Choose a string height gauge with the desired measurements (typically 0.025" – 0.125").
- Fret Placement: Position the gauge’s arm perpendicular to the fretboard at the 12th fret.
- Measurement Reading: Press down on the string at the 2nd fret, ensuring it rests on the fret. Read the measurement displayed on the gauge arm, which indicates the string height above the 12th fret.
- Repeat Process: Repeat the measurement for each string, ensuring consistent pressure and perpendicular gauge placement.
Acceptable String Height Ranges
The ideal string height varies based on personal preferences and playing style. However, generally acceptable ranges are provided in the table below:
| String | Height (12th Fret) |
|---|---|
| 12th String | 0.060″ – 0.070″ |
| 11th String | 0.065″ – 0.075″ |
| 10th String | 0.070″ – 0.080″ |
| 9th String | 0.075″ – 0.085″ |
| 8th String | 0.080″ – 0.090″ |
| 7th String | 0.085″ – 0.095″ |
| 6th String | 0.090″ – 0.100″ |
| 5th String | 0.095″ – 0.105″ |
| 4th String | 0.100″ – 0.110″ |
| 3rd String | 0.105″ – 0.115″ |
| 2nd String | 0.110″ – 0.120″ |
| 1st String | 0.115″ – 0.125″ |
Remember, these ranges are approximate and may be adjusted to suit individual playing preferences.
Adjusting the Truss Rod
The truss rod is a steel rod that runs through the neck of the guitar, just beneath the fingerboard. It is used to adjust the curvature of the neck, which can have a significant impact on the action of the guitar. If the neck is too curved, the strings will be too high off the fingerboard, making it difficult to play. If the neck is too flat, the strings will be too close to the fingerboard, causing buzzing and fretting out.
To adjust the truss rod, you will need a truss rod wrench. These wrenches are typically included with new guitars, but they can also be purchased separately. Once you have a wrench, follow these steps:
1. Locate the truss rod nut. It is typically located at the headstock of the guitar, just behind the nut that holds the strings in place.
2. Insert the wrench into the truss rod nut and turn it clockwise to tighten the truss rod or counterclockwise to loosen it.
3. Tighten or loosen the truss rod in small increments, checking the neck curvature after each adjustment.
4. Once the neck curvature is correct, tighten the truss rod nut securely.
Checking the Neck Curvature
To check the neck curvature, place a straightedge across the frets. The straightedge should be parallel to the fretboard and should touch the frets at the first and last frets. If the neck is correctly curved, there should be a slight gap between the straightedge and the frets in the middle of the neck.
| Neck Curve | Description | Action |
|---|---|---|
| Upbow | The neck is curved away from the strings. | The strings will be too high off the fingerboard. |
| Backbow | The neck is curved towards the strings. | The strings will be too close to the fingerboard. |
| Straight | The neck is perfectly straight. | The action will be correct. |
Fine-Tuning the Saddle Height
The saddle height plays a crucial role in the guitar’s overall playability and sound. To adjust the height, you’ll need a ruler and a set of hex keys (Allen wrenches). Follow these steps:
- Measure the current saddle height: Place the ruler’s edge on the 12th fret and hold it parallel to the guitar’s neck. Measure the distance from the ruler’s edge to the top of the saddle at the 12th fret. This distance is the saddle height.
- Adjust the saddle height: Once you know the current height, you can adjust it to your preferred level. Most acoustic guitars have an ideal saddle height range of 2.5 to 3.5 millimeters. If the action is too high, the strings will be too far from the fretboard, making it difficult to play. If the action is too low, the strings may buzz against the frets.
- Use a hex key to adjust the saddle height: Locate the adjustment screws on the bridge. These screws are typically recessed into the bridge and may require a specific hex key size. Turn the screws clockwise to raise the saddle and counterclockwise to lower it. Make small adjustments at a time, checking the action and measuring the saddle height as you go.
Tip: The saddle height affects intonation, which is the accuracy of the guitar’s pitch. If you adjust the saddle height significantly, you may need to adjust the intonation later.
| String | Recommended Height (mm) |
|---|---|
| High E (1st) | 2.5-2.8 |
| B (2nd) | 2.6-2.9 |
| G (3rd) | 2.7-3.0 |
| D (4th) | 2.8-3.1 |
| A (5th) | 2.9-3.2 |
| Low E (6th) | 3.0-3.3 |
Leveling the Frets
Regularly checking and leveling the frets on your guitar ensures a smooth and consistent playing experience. Here’s a detailed guide to help you achieve optimal fret leveling:
Gather Your Tools:
You will need:
- Fret leveling beam or file
- Sandpaper (various grits)
- Markers or felt pens
Step-by-Step Instructions:
1. Inspect the Frets:
Examine the frets carefully for any high or low spots. Use a straightedge or fret leveling beam to determine which frets need adjustment.
2. Mark the Frets:
Mark the high frets with a marker or felt pen. This will help you identify them during the leveling process.
3. File the Frets:
Securely hold the fret leveling beam or file perpendicular to the fretboard. Start filing gradually from the highest fret, applying moderate pressure. Avoid filing too aggressively, as this could damage the frets.
4. Sand and Polish the Frets:
After filing, sand the leveled frets using sandpaper of various grits. Start with coarser sandpaper (e.g., 240 grit) to remove excess material and gradually move to finer sandpaper (e.g., 1000 grit) to smooth the surface. Finally, polish the frets using a polishing cloth or compound for a glossy finish.**
<table>
<tr>
<th>Sandpaper Grit</th>
<th>Purpose</th>
</tr>
<tr>
<td>240</td>
<td>Remove excess material</td>
</tr>
<tr>
<td>600</td>
<td>Smooth the surface</td>
</tr>
<tr>
<td>1000</td>
<td>Final smoothing</td>
</tr>
</table>
5. Remove Markers:
Once the frets are leveled and polished, remove any marks or residue using a cleaning cloth.
6. Recheck the Level:
Use the straightedge or fret leveling beam to recheck the level of the frets. Adjust any remaining high or low spots as necessary.
Inspecting and Cleaning the Nut
The nut is a small but crucial component that holds the strings in place at the headstock. A clean and properly adjusted nut is essential for maintaining optimal string height and intonation.
Cleaning the Nut
- Remove the strings carefully, keeping track of their original positions.
- Use a soft-bristled brush or a toothpick to gently remove any dirt or debris from the slots.
- Avoid using sharp tools that can damage the nut.
- If necessary, apply a small amount of guitar cleaner or denatured alcohol to a clean cloth and wipe the nut to remove any remaining dirt.
- Allow the nut to dry completely before restringing the guitar.
| Slot | String |
|---|---|
| 1 | E (high) |
| 2 | B |
| 3 | G |
| 4 | D |
| 5 | A |
| 6 | E (low) |
Adjusting the Intonation
Intonation refers to the accuracy of the guitar’s pitch across the entire fretboard. To adjust the intonation, follow these steps:
1. Tune the Guitar
Start by tuning your guitar using a tuner or tuning fork.
2. Check the Intonation
Play the 12th fret harmonic on the 6th string (E). Then, fret the 12th fret on the same string. If the fretted note is sharp (higher pitch), the saddle needs to be moved back. If it’s flat (lower pitch), the saddle needs to be moved forward.
3. Adjust the Saddle
Use a screwdriver or Allen wrench to loosen the screws holding the saddle down.
4. Move the Saddle
Slide the saddle forward or back as needed, then tighten the screws.
5. Fine-Tune
Repeat steps 2-4 until the fretted and harmonic notes sound in unison.
6. Adjust the Other Strings
Repeat the above steps for each string, adjusting the saddles as necessary to ensure accurate intonation across the entire fretboard.
The following table provides a summary of the adjustments required:
| String | Adjustment |
|---|---|
| 1st (E) | Move saddle forward if sharp, back if flat |
| 2nd (B) | Move saddle back if sharp, forward if flat |
| 3rd (G) | Move saddle forward if sharp, back if flat |
| 4th (D) | Move saddle back if sharp, forward if flat |
| 5th (A) | Move saddle forward if sharp, back if flat |
| 6th (E) | Move saddle back if sharp, forward if flat |
Setting the Relief Angle
The relief angle, or neck relief, is the slight curvature in the neck that allows the strings to vibrate without buzzing against the frets. This curvature is measured using a feeler gauge, which is a thin piece of metal with different thicknesses.
Using a Feeler Gauge
To set the relief angle, insert a feeler gauge between the 7th fret and the bottom of the string. With the string pressed down at the first and 14th frets, the feeler gauge should slide through with a slight amount of resistance.
For most guitars, a relief angle between 0.008 inches and 0.012 inches is recommended. Refer to the table below for specific measurements based on the scale length of your guitar.
| Scale Length | Relief Angle |
|---|---|
| 24.75 inches | 0.008 inches – 0.012 inches |
| 25.5 inches | 0.010 inches – 0.014 inches |
| 26.5 inches | 0.012 inches – 0.016 inches |
If the feeler gauge cannot slide through or slides through too easily, the relief angle needs to be adjusted. To increase the relief angle, loosen the truss rod nut slightly using a hex key or truss rod wrench. To decrease the relief angle, tighten the truss rod nut slightly.
Once the relief angle is set correctly, the guitar should have good intonation and playability without any buzzing or fretting out.
Using a Radius Gauge
A radius gauge is a tool that helps you measure the radius of the fretboard. The radius is the curvature of the fretboard, and it affects the action of the guitar. A smaller radius will result in a lower action, while a larger radius will result in a higher action.
To use a radius gauge, simply place it on the fretboard and bend it until it conforms to the curve of the fretboard. The number on the gauge will indicate the radius of the fretboard. If the radius of the fretboard is not within the recommended range, you may need to adjust the neck relief or the truss rod.
| Radius | Recommended Action |
|---|---|
| 7.25 inches | 0.08 inches at the 12th fret |
| 9.5 inches | 0.10 inches at the 12th fret |
| 12 inches | 0.12 inches at the 12th fret |
It is important to note that the recommended action height is just a starting point. You may need to adjust the action to your personal preference. If you are not sure how to adjust the action, it is best to take your guitar to a qualified guitar technician.
Tightening Loose Hardware
The hardware on your guitar, such as the bridge, tuners, and truss rod, can become loose over time. This can cause buzzing, rattling, and other problems with the guitar’s intonation and playability. To tighten loose hardware, you will need a few basic tools, such as a screwdriver, a wrench, and a hex key. Start by inspecting the bridge. The bridge is responsible for holding the strings in place and transferring their vibrations to the body of the guitar. If the bridge is loose, it can cause the strings to buzz or rattle. To tighten the bridge, use a screwdriver or a wrench to turn the screws that hold it in place. Be careful not to overtighten the screws, as this can damage the guitar.
Tightening the Tuners
The tuners are responsible for keeping the strings in tune. If the tuners are loose, the strings can slip out of tune easily. To tighten the tuners, use a hex key to turn the screws that hold them in place. Again, be careful not to overtighten the screws.
Tightening the Truss Rod
The truss rod is a metal rod that runs through the neck of the guitar. The truss rod is used to adjust the neck’s relief, which is the amount of curvature in the neck. If the neck is too bowed, the strings will be too high off the fretboard and will be difficult to play. If the neck is too flat, the strings will be too close to the fretboard and will buzz when played. To adjust the truss rod, use a hex key to turn the nut that is located at the headstock end of the neck. Turn the nut clockwise to tighten the truss rod and reduce the neck’s relief. Turn the nut counterclockwise to loosen the truss rod and increase the neck’s relief.
Here is a table summarizing the steps involved in tightening loose hardware:
| Component | Tool | Direction |
|---|---|---|
| Bridge | Screwdriver or wrench | Tighten the screws that hold the bridge in place. |
| Tuners | Hex key | Tighten the screws that hold the tuners in place. |
| Truss rod | Hex key | Turn the nut clockwise to tighten the truss rod and reduce the neck’s relief. Turn the nut counterclockwise to loosen the truss rod and increase the neck’s relief. |
Professional Setup Considerations
10. Truss Rod Adjustment
The truss rod is a metal rod that runs inside the neck of the guitar. Its purpose is to counteract the tension of the strings and keep the neck straight. Over time, the neck can bow or warp, which can affect the action. To adjust the truss rod, you will need a specialized wrench.
| Turn Clockwise to: | Turn Counterclockwise to: |
|---|---|
| Straighten the neck | Bow the neck |
To make a truss rod adjustment, follow these steps:
1. Loosen the truss rod nut by turning it counterclockwise.
2. Use the wrench to turn the truss rod in small increments.
3. Check the neck after each adjustment to see if it is straight.
4. Once the neck is straight, tighten the truss rod nut by turning it clockwise.
How to Adjust the Action on an Acoustic Guitar
The action on an acoustic guitar refers to the distance between the strings and the fretboard. A properly adjusted action can significantly improve the playability and tone of the guitar. Here’s a step-by-step guide on how to adjust the action on your acoustic guitar:
- Measure the Action: Use a feeler gauge or a business card to measure the action at the 12th fret. The ideal action is around 2/32 inches (1.6 mm) for the low E string and 1/16 inches (1.6 mm) for the high E string.
- Adjust the Truss Rod: If the action is too high or too low, you can adjust the truss rod to bring it closer to the correct height. Turn the truss rod nut clockwise to raise the action and counterclockwise to lower it. Make small adjustments and allow the guitar to settle for a few minutes before re-measuring.
- Adjust the Bridge: If the action is still too high or too low after adjusting the truss rod, you can adjust the bridge. Most acoustic bridges have individual saddle pieces that can be raised or lowered to change the action. Use a hex wrench to make adjustments.
- Check the Saddle Slot: If the saddle is not sitting properly in the slot, it can affect the action. Inspect the slot for any debris or damage and make sure the saddle is securely seated.
- Test and Repeat: After making an adjustment, re-measure the action and test the guitar. Make further adjustments as needed until the action is correct for your playing style and preferences.
People Also Ask About How to Adjust the Action on an Acoustic Guitar
How can I tell if the action on my guitar is too high or too low?
If the action is too high, the strings will be difficult to press down and the guitar will have a ‘buzzy’ sound. If the action is too low, the strings will be too close to the fretboard and may buzz when played.
Can I adjust the action on my guitar myself?
Yes, you can adjust the action on your acoustic guitar yourself if you have the proper tools and knowledge. However, if you are not comfortable making adjustments, it is recommended to take your guitar to a qualified luthier.
What tools do I need to adjust the action on my guitar?
You will need a feeler gauge or business card to measure the action, a hex wrench or screwdriver to adjust the saddle, and a wrench or socket to adjust the truss rod.
