With a few tools, you can perform a handful of tasks that will make your new axe play better and stay in tune. This article is for folks who already know how to tighten loose parts, raise and lower string saddles or bridges, and adjust their truss rods—though I’ll share a tip on how to check it with even more accuracy.
Is that big bulky stock nut uncomfortable on your hand? Let’s trim it down and reshape it. If the action feels high and the neck looks straight, I’ll show you how to lower the action. And haven’t we all swapped out pickups and wondered, “Do they really sound better, or do I think that just because they’re new?” Before you swap your pickups, I’ll share some pickup-height measurements that might make you change your mind.
But wait! There’s more. With everything feeling and playing great, does moving into the upper register start to sound out of tune? Intonation is very easy to check and adjust. When you go to vibrato or hold a note, do the frets feel “sandy”? Are the fret ends rubbing against your hand while you play? Let’s flush and polish those up.
To be clear, we’re not swapping out anything on your new guitar: We’re simply refining the setup. Be sure to go online to see eight videos I made showing various processes covered in this story.
Begin the Beguine
There is an order of operations for best results. Neck relief is the first item to dial in, followed by getting the nut slots cut to the proper depth. After that, setting your string and pickup heights is in order. The final step is setting intonation.
Fret polishing is its own event and can happen anytime between string changes. Getting the frets feeling comfortable and well-polished will take some time and attention. You’ll also need some specialized tools as well as some that can be found in most households. Check the box for my list.
Tools You’ll Need
All of the specialized tools in this list are available through online suppliers, including StewMac and Amazon.
- 6" Ruler with measures in 64ths
- String action gauge [Photo 1]
- Miscellaneous screwdrivers
- Allen wrenches
- Radius blocks
- Understring radius gauges (with the radius on the bottom and the top)
- Fret-end dressing file
- Micro-Mesh sticks [Photo 2]
- Tape (low tack)
- Cotton swabs
- Paper towels (blue shop towels preferred)
- Clean cotton rags
- Nut files [Photo 3]
- Stikit sandpaper
- Tri-Flow lubricant
- Capo
- Feeler gauges
- Simichrome polish
Polishing the Frets
Photo 4
Let’s start with the most Zen of these tasks: fret polishing.
Tape off the fretboard using low-tack tape, exposing only the frets. De-tack each piece of tape on your clothing or maybe a rag—I use my jeans or my sweatshirt. Making it less sticky helps prevent pulling finish off a maple fretboard or the neck. Taping the fretboard also prevents putting any cross-grain scratches into it while you file and polish. You can choose to tape off the entire fretboard or work your way down one fret at a time. Dealer’s choice.
One thing to note about tape, any tape: Even when you de-tack it, you do not want to leave it on overnight. If that happens, rub the tape with your finger, which will break the surface tension. Then carefully pull the tape off from a corner, making sure you’re pulling it off at an angle and not at a straight line with the fretboard edge.
Every fret end has a small burr on the corner from the initial fret job. The fret-end dressing file has a non-marring smooth side for rounding the fret end, and a safe square edge for getting into the corner of the fret end. So, take the fret-end dressing file, use the squared off-side, and file both corners of the fret end [Photo 4].
How to Polish Frets
Here’s how easy it is to polish and smooth frets.
One or two strokes is all you’ll need. Then, using the non-marring side of the file, slightly round off the fret ends.
Photo 5
With the file positioned vertically, file downward to make the fret end flush with the edge of the fretboard.
Photo 6
For a nice, rounded-off look, polish the frets using the same rounding motion from the previous step, working through all three grits of the Micro-Mesh stick.
Photo 7
Then, polish both the sides and the top of the frets.
Photos 8 (top) & 9 (bottom)
Using a soft cloth and Simichrome, buff every fret. This will give you a great shine and help prevent oxidation. Now it’s time to remove the tape and condition the fingerboard if it needs it.
Note: Every fret has two fret ends to clean up and polish along with the fret itself. This is a fair amount of handwork. If you’ve never done it, you will get tired and need a break. Take that break. Take multiple breaks. Let the process take however long it requires without rushing. If you’re new, do all the fret polishing over a weekend or a few days. It should be fun, not painful. If it is difficult, call your local luthier and hire them to do it for you.
Adjusting Neck Relief
Photo 10
Neck relief refers to the slight amount of concave bowing intentionally created in the neck of a guitar or bass by adjusting the truss rod. For the safety of the guitar, be sure to slack the strings before doing any adjustments to the truss rod. Neither you nor your guitar needs to be tense during this process.
Before whipping out an Allen wrench for the truss rod, start by sight-checking the neck’s straightness. You can sight the neck with the guitar on its back, but I like to put it on edge and look at it that way. It’s easier to see how much curve there is when the guitar is on its side. I feel like gravity plays tricks on my eyes when I sight the neck with the guitar on its back. When I play the guitar, it’s on its side anyway, so looking at it from this vantage point is best.
Tune the guitar to pitch, put a capo on the first fret, and press fret 15 with your left hand.
Photo 11
With your right hand, take a feeler gauge and check the gap at frets 7 through 9 (left-handed players, flip your hands around) [Photo 11].
From the top of the fret to the bottom of the string, the gap is usually anywhere from .003" to .012", depending on the feel you are going for. The feeler gauge should fit just between the top of the fret and the bottom of the string. The string shouldn’t move. This will tell you how much “relief” is in the neck. If you find this challenging, keep going—this will take some practice.
When dialing in the relief, I go back and forth between adjusting the truss rod and the string action. Getting the strings low and playing clean on a budget axe can be a challenge. Usually the fretwork isn’t that great, and in the upper register the frets can be unlevel, causing buzzes and clanks. If you need to raise the string action to get the notes to play clean, some fret leveling may be in order. (For more on fret leveling, go online to our article “About Fret Leveling,” from the December 2007 issue.) For good energy transfer, the neck should be as straight as possible. If the neck is straight and the frets are not level, the strings will buzz with low action.
In general, the flatter the radius on the fretboard, the straighter you can get the neck with the truss rod adjustment. On a fretboard with a 12" radius, you should be able to get .005" relief, and on a vintage 7.25" radius board you may need as much as .014" relief. The only way to get better at checking and setting relief is practice.
Refining the Nut
String buzzes, pinging noises when you tune, strings sticking in the slots, and too much string motion in the nut slots are all indicators of trouble. Before getting out the sandpaper and Micro-Mesh sticks, be sure you know if your guitar’s nut is TUSQ or bone. TUSQ is softer, so you should leave TUSQ nut slots a little higher. This leaves room for the TUSQ to wear without causing buzzing on the first fret. With bone, you can cut the slots lower, because it holds up to string wear.
How to Shape Your Guitar's Nut
Watch as Dave Helmer sands down the back half of a nut and creates a smooth finish.
The back side of the nut is usually very bulky and could often stand to lose some material to be more comfortable on your hand. So, let’s start there. Tape off the neck and headstock around the nut using a few layers of tape to protect the headstock face and fretboard. Then, slack the strings and pull them to either side of the nut.
Sand a bevel into the backside—the side closest to the headstock—of the nut using P320 and P400 grit Stikit sandpaper on a flat sanding stick.
Photo 12
The bevel should start at the back of the nut and come forward about one-third to one-half the thickness of the nut [Photo 12]. Use P320 for most of the sanding and switch to P400 for the last 5 to 10 strokes.
Next, take a fresh Micro-Mesh stick and work through the various grits to buff/round over the bevel you’ve sanded into back of the nut, so it looks and feels good.
Photo 13
TUSQ nuts are often tall, and the strings sit deep in the slots.
Photos 14 (left) & 15 (right)
Wound strings require 50 percent of the diameter of the string to sit in the nut slot, with the other 50 percent above the top of the nut surface. The plain strings should be flush with the top of the nut. Take a look at the wrong appearance [Photo 14] and the correct look [Photo 15] for properly seated strings.
How to Sand Your Guitar's Nut
Our luthier shows you how to use a radius block and sand down a nut.
Use a radius block that matches the radius of your fretboard.
Photo 16
With P320 and P400 grit Stikit sandpapers, use mild pressure to sand down the top of the nut. Sand a bit and check your progress by setting the strings in the slots and putting a little tension on them. Tuning to pitch isn’t necessary. Use the P320 for most of the sanding, and switch to P400 when you are close to the 50/50 height for the wound strings. The radius block sanding will leave a flat, sharp edge on each side of the TUSQ nut [Photo 16]. To round over the sharp edge, use the sanding block and Micro-Mesh stick.
Use the coarse grit of a Micro-Mesh stick to round over and blend the bevel from the back into the top of the nut. Work through the grit gauges until it’s smooth. There is a fine balance between the bevel at the back of the nut and the top radius of the nut. Go back and forth between the two steps to get a nice, finished look and a nut that functions at optimal levels.
… And Refining the Nut Slots
Photo 17
Nut height is the distance from the top of the first fret to the bottom of the string. A good height on the wound strings is about .020", and for the plain strings about .015". Measuring this gap with a feeler gauge can be tricky because of the fretboard radius. Many repair folks do this by eye and feel, based on experience. It takes some practice. A good check: At pitch, fret the third fret and check for a small gap between the string and the top of the first fret.
How to Widen Your Guitar's Nut Slots
A diamond file can make quick work of deepening and widening nut slots.
The bottom of the string should be sitting on the bottom of the front half of the nut slot [Photo 17]. File down each nut slot to its proper depth using the corresponding nut file. There are diamond nut files on the market in multiple sizes to accommodate many string gauges. Make sure to keep your strokes straight. The standard-toothed files have less sizes and usually require rolling them from side to side to get a well-fit string.
Next, using a proper-sized file, round over the bottom back half of the nut slots down, toward the face of the headstock and away from the strings. This will allow the strings to move freely during tuning or bending, while still having support from the front half of the slot.
How to File D and G String Slots on Guitar
Photo 18
On guitars with 3x3 headstock configurations, the D and G strings need the back half of the slots feathered out away from the center, so the string has a direct path to the tuner post. Using a file that is one size bigger than the string and rolling it side to side on the back of the nut slot will give the string a straight path to the tuner post. Photo 18 is my illustration showing which slots need feathering.
Watch How to File D and G String Slots on Guitar
The D and G nut slots require special attention on 3x3-style headstock configurations.
Additionally, use pencil lead to lubricate the slots. Just get in there with the point of a pencil and mark the slot with its graphite. You might also put a drop of Tri-Flow on the front of the string tree. Tri-Flow will run down the string, so take a cotton swab or cloth to clean up any excess. Tri-Flow has Teflon in it, so you don’t need much.
Adjusting String Action
Photo 19
First, find your string height by measuring the string action at the 17th fret on a Fender-style guitar and at the 15th fret on a Gibson-style instrument.On electric guitars, action can range from 3/64" to 3/32", depending on the player’s comfort. My preferences are 1/16" on the treble side and 5/64"on the bass side on both Fender- and Gibson-style guitars measured at the appropriate fret.
How to Adjust Guitar Action
Here’s a look at how our author adjusts the action.
Always loosen the string tension before making action adjustments. This will save wear and tear on the small bridge components. Take either a 6" ruler or a string action gauge and set it on the frets. Measure from the top of the fret to the bottom of the string [Photo 19].
If the action is high, you will lower that string’s saddle or that side of the bridge. If it is low, you will raise it. Make sure the individual saddles are sitting square and upright to the face of the bridge. You do not want them sitting at an angle or leaning over. This will cause buzzing.
The bottom of the strings should match the radius of the fretboard when measured with an understring radius gauge.
Photo 20
Start your adjustment with the outside strings, working toward the center. On Fender-style guitars, set the two outside strings to the height you want and have the middle four strings a bit higher than that. Bring the gauge up from underneath and just touch the two outside strings. Then, bring the strings down a little at a time until the radius matches.
On a Gibson-style Tune-o-matic, the saddles are not individually adjustable. So, if the radius doesn’t match, the saddles will need to be filed. To do this, I recommend using toothed nut files and a rolling side-to-side motion. Do a little work and check your progress. Remember to slack your strings when adjusting the saddle or bridge up or down.
Changing Pickup Height
Photo 21
Finally, let’s take a look at pickup-height adjustment. First, to check pickup height, use the two outside strings again. Press the top wound string on the last fret and measure the distance from the top of the pole piece to the bottom of the string [Photo 21]. This distance can range from 3/64" to 1/8". My preferences are 1/16" on the treble side and 5/64" on the bass side.
Adjusting Guitar Pickup Height
Dave Helmer walks you through the process of adjusting the height of your guitar’s pickups.
On most styles of pickups, there are height adjustment screws on either side of the pickup to raise or lower it. The closer the pickup gets to the strings, the more present string frequencies become. If you get too close, the magnetic pull can affect the string’s vibration and you may hear some strange sounds as you go into the upper register.
On Strats, the neck pickup is regularly set too close, and at the 12th fret and above, the low E and A can sound choked, honky, and not clear. Lowering the neck pickup with a screwdriver usually solves this issue.
Setting Intonation
Photo 22
If you can’t get your guitar accurately in tune, you might need to check its intonation. Adjust all saddles as far back as possible so every string will play flat at the 12th fret. You will adjust the saddles forward, gradually making the octave play sharper until it’s in tune with the open string [Photo 22].
Adjust Your Guitar's Intonation
With a tuner and a screwdriver, Dave Helmer shows you how to adjust your guitar’s intonation.
Depending on your vibrato style, experiment with intonating the plain strings slightly flat. Use your ear and do what sounds good. Sometimes, the plain strings can have perfect intonation, but playing with vibrato can make them sound sharp.
To fine-tune intonation, the individual bridge saddles must be adjustable. Once the intonation is set, recheck the string radius using the understring radius gauge and adjust as needed. The radius can change as the saddles come forward during intonation.
Tri-Flow is great for lubricating saddle parts. Put a small drop on the saddle-height adjustment screws and capillary action will suck it in. Adjust the saddle up and down a few times to coat the threads. Clean up any excess with a cotton swab or cloth. Put a drop or two onto a cotton swab and apply the Tri-Flow to the top of each saddle where the string rests. This will help strings move freely during tuning and after any bends or vibrato.
And that’s it! For a relatively small investment in tools and time, you’re now ready to supercharge your new guitar—and maybe your long-treasured axes, too.
Fig. 1. Our project guitar—the Zombie-Caster. Photos by John LeVan
At some point, the neck goes out of adjustment on virtually every guitar. The culprit is typically weather, humidity, or changes in altitude. When the weather changes, so does anything made from wood. Likewise, as the humidity changes, the wood in a guitar will contract or expand, and this causes the instrument to drift out of adjustment.
Fear not! With a few simple tools, you can adjust your neck and be back in business in just a few minutes. To illustrate the process, I'll turn to a Fender Stratocaster with a typical modern truss rod and a rather unconventional paint job. I call it my Zombie-Caster (Fig. 1).
There are several types of truss rods: single- action, double-action, and non-adjustable. Though they work in different ways, all truss rods are designed to counteract the tension of a guitar's strings, which are constantly pulling on the neck. Left unchecked, this tension would bow the neck forward.
Fig. 2. A single-action truss rod creates back-bow to counteract string tension.
A single-action truss rod moves the neck in one direction (Fig. 2). By tightening the rod, you force the neck into a convex shape known as "back-bow." Conversely, when you loosen the rod, it relieves the tension inside the neck and the strings will pull the neck forward, creating a concave shape called "fore-bow."
The single-action rod will eventually run out of adjustment. Once the rod has reached a fully relaxed position, by itself the neck won't offer any more fore-bow. This limits the adjustability and is a problem if the neck wasn't made properly when the truss rod was installed.
Fig. 3. A double-action truss rod allows both back-bow and fore-bow.
Double-action truss rods force the neck in either direction (Fig. 3). I've used this type of truss rod in several of my guitars and I really like them. You tighten the double-action rod to force a back-bow or loosen it to force a fore-bow. The key difference between a single- and double-action rod is the latter has the ability to create fore-bow. With a double-action rod, you can actually force the neck into either a concave or convex shape.
Non-adjustable truss rods are self-explanatory. Typically composed of wood, graphite, or metal, they cannot be manipulated. They are also referred to as a K-Bar or steel re-enforced neck. These rods are usually found in older archtops, classical, and some flattop guitars.
Step 1: Gather your tools and prepare your workspace.
You only need a few tools for this project, but it's very important to use the correct ones. Here are the three items I use when adjusting a truss rod:
- Action gauge (available from stewmac.com)
- Capo
- Correct neck wrench (typically, this is supplied with the guitar)
The measurements are very small on an action gauge, so you'll need good lighting to read them.
Step 2: Measure current neck relief.
Fig. 4. To measure relief, clamp a capo on top of the 1st fret and then hold down the 6th string at the last fret.
Before you adjust the truss rod, you need to assess the neck's current state. Measuring the amount of "relief "—i.e., intentional fore-bow to provide room for a vibrating string—in a neck can be tricky. I suggest using a light with a built-in magnifier. You'll need the magnifier when taking measurements that vary from 1/64" (.015) up to 3/64" (.045). These are very small increments, but just a few thousandths of an inch can make a big difference in playability.
Here is my process for measuring existing neck relief:
- Tune the guitar to pitch.
- Place a capo on top of the 1st fret (Fig. 4).
- Hold down the 6th string at the last fret.
- Place the action gauge behind the 6th string, resting on the frets (Fig. 5).
- Gently slide the gauge from the 1st to the last fret, taking note of the space between the fret and string as indicated by the gauge's markings.
Fig. 5. Using a Stewart-MacDonald action gauge to precisely determine neck relief.
Write down the greatest distance—the biggest gap you encounter—from the top of the frets to the bottom of the string. This distance tells us how much relief or fore-bow the neck has. This measurement can vary dramatically from one guitar to another.
If there is no relief or fore-bow, then either your neck is dead flat or has back-bow. This means you need to loosen the truss rod to add the proper amount of relief.
Step 3: Determine the correct amount of relief.
How much relief do you need? This depends on how you play: If you're a light strummer, you only need the minimum amount of relief. If you strum hard or use a capo, you'll need more relief—a larger gap between the frets and vibrating strings.
For a light-to-medium strummer, relief measuring about .010 is plenty. This will also help keep the action low. For an aggressive strummer (or if you use a capo), .015 to .020 is normal. This will help prevent string rattle and buzzy notes. Keep in mind that these measurements are the distance from the top of the frets to the bottom of the 6th string.
Step 4: Adjust the truss rod.
There are several different ways to adjust a truss rod. Some truss rods require a screwdriver; others use an Allen wrench or even a socket wrench. Make sure you have the correct tool for the job!
As for my Zombie-Caster, it has .020 relief, as you can see in Fig. 5. That's more than necessary for my playing style and explains why the action feels so high.
Fig. 6. Adjusting the truss rod with a 1/8" Allen wrench.
Because I don't play hard or use a capo, I'll adjust the relief to be around .010 (Fig. 6). To adjust this truss rod, I need a 1/8" Allen wrench.
Fig. 7. Some necks need to be removed to access the truss rod.
Sometimes the access for the truss rod is at the heel of the neck. If that's the case, depending on the design, you may have to remove the neck to adjust the rod (Fig. 7). Vintage and vintage-style reissue Fenders, for example, require neck removal. Of course, this means remounting, restringing, and retuning between each adjustment. That's okay—be patient and make small adjustments. It takes time to get this right, but the effort is well worth it.
To add relief or fore-bow, turn the wrench counter-clockwise. If the neck needs less relief turn the wrench clockwise. (If you're looking directly at the truss rod nut, you can think "righty-tighty, lefty-loosey.") Always retune and remeasure after every adjustment.
Tip: If the truss rod won't turn smoothly— stop! There could be a problem with it. Remember, never force a truss rod. If you break it, it will cost a fortune to repair and probably trash the neck. If you're not comfortable adjusting your truss rod, consult a qualified repair technician.
Because my Zombie-Caster has .020 relief, I needed to turn the wrench clockwise to tighten the truss rod and reduce the gap. After turning the wrench about 1/3 of a revolution, the neck was right where I wanted it.
Wrap. If you carefully follow this procedure, you'll be able to adjust your truss rod and keep your guitar playing its best. Don't be surprised if you have to make this adjustment once or twice a year. The frequency really depends on your climate and how much traveling you do. And if you change string gauge, you'll also want to tweak your truss rod to accommodate the increased or decreased string tension.
We'll tackle another DIY project next month, so see you then.
[Updated 7/21/21]