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.
I unwrapped a new Fender hex key (more about the condition of your tools in a moment) and inserted it into the truss rod nut. But instead of finding a secure grip, I felt the tool spin around inside the nut. Oh, that sinking feeling: I realized the nut’s socket was stripped, which is very bad news for this particular Strat.
Why? The truss rod nut on this type of Strat is recessed into the neck and surrounded by wood (Photo 1), so when the socket that holds the truss rod tool is stripped out, you only have two options: perform major surgery to remove the stripped nut and replace it with a new one, or buy a replacement neck. Realistically, it would cost more to perform the extraction, so I advised my client to contact Fender about getting a new neck.
Fortunately, not all Fender guitars have a recessed truss rod nut—in fact, many guitars don’t. You can often replace a stripped truss rod nut, and it’s not a tricky repair if you know what you’re doing. Inexpensive replacement nuts are available from such suppliers as Stewart-MacDonald, Luthiers Mercantile, and Allparts.
Different types of truss rod nuts.
Before we discuss why a truss rod nut might fail and how to fix it, let’s explore several common types of nuts used on guitars. You adjust some nuts by inserting a tool into them, others by enclosing them with a nut driver or special socket wrench.
Using the wrong tool to adjust a nut is the most common cause of truss rod problems.
The nut placement varies too: On Taylor and Gibson instruments, for example, the truss rod nut is typically located at the headstock, under a plastic or wood cover. These are among the easiest to remove. Some Fender guitars have a “bullet” truss rod nut at the headstock; these are not recessed and can be removed without surgery. Older Fender guitars have a truss rod nut at the heel of the fretboard, and these are very easy to remove, once you take off the neck. Some modern electrics have an exposed “wheel” nut located at the heel, and these can be adjusted without removing the neck.
Some acoustics, such as Takamine and modern Martins, have a truss rod nut that you access through the soundhole by inserting the tool through a small hole in the upper top brace (located between the soundhole and neck block). In some cases, this hole is just big enough for a wrench to poke through, but not big enough to accommodate the nut. The brace can be removed, but that is considered a surgical procedure, which is why some luthiers opt to simply enlarge the hole to remove the nut.
Truss rod tools vary, as well.
Some require a hex key (Allen wrench), while others take a flathead or Philips screwdriver, a nut driver, a mini socket wrench, or a small metal rod. To learn more, read “Demystifying Truss-Rod Tools.”
Why truss rod nuts fail.
There are three main reasons why you might have a problem with a truss rod nut:
- Hardware defect.
- The wrong size tool was used in an attempted adjustment.
- The correct tool was used, but it was worn.
A manufacturing defect is pretty rare, but they happen. When you think about how many guitars are built (probably millions each year), there’s a good chance a few lemons are going to squeeze through. It usually comes down to poor quality metal or slight discrepancies in manufacturing tolerances.
Photo 2
Using the wrong tool to adjust a nut is the most common cause of truss rod problems. I’ve seen many nuts that were ruined because someone decided to force the wrong tool around or into them. Photo 2 shows a Fender bullet nut that suffered this fate. Once a socket’s edges have been rounded like this, the hex key can’t grip the nut to turn it.
Photo 3
Recently I removed the neck on a client’s vintage Tele to adjust the truss rod. The nut looked like Photo 3, which illustrates what happens when someone uses a screwdriver that’s the wrong size. The slots get deformed, and this makes truss rod adjustments difficult. The good news is these nuts are easy to remove, even when they’re butchered like this, but unfortunately it’s nearly impossible to find a “period correct” replacement. Sure, there are plenty of aftermarket parts available, but for a vintage guitar, it’s imperative to use period-correct parts to maintain its value. I mention this simply to drive home the importance of using the correct truss rod tool—one that fits snugly.
Worn-out tools will also damage a truss rod nut. For example, if the truss rod requires a hex key and its edges have become worn and rounded, it can in turn round out the inside of the nut. It’s important to check your tools to ensure they won’t damage your guitar.
A basic guitar tech principle: Replacing worn tools is much cheaper than fixing the damage they can cause.
Tools for removing a stripped nut.
There are times when you can use the specified tool to remove the nut, but often you have to be creative. Once when working on a Gibson electric, I had to remove a hex nut that was so stripped that a nut driver wouldn’t grip it. Fortunately, a pair of needle-nose pliers did the job, but you must be careful to avoid stripping the nut more than it already is as you remove it. An improvised tool can easily damage the headstock, so proceed with caution.
Important: Always slacken the strings before you remove the truss rod nut.
Photo 4
In other cases, I’ve used a small flathead screwdriver to extract a nut when a hex key wouldn’t work. For example, by gently tapping the screwdriver into this stripped bullet nut (Photo 4), I was able to get it to catch hold. I turned the screwdriver counter-clockwise and voilà, the nut came off.
I’ve also used a screw extractor, a tool that looks like a drill bit, but with a twist: Screw extractors have tapered, reversed cutting threads designed to dig into a damaged screw and grip it tighter as you turn the extractor counter-clockwise while carefully applying pressure. The counter-clockwise movement backs out the damaged screw—typically its head is mangled or broken off—even as the extractor bores deeper into the screw shaft. I do this manually using a T-handle, but you can also use vice-grips with a screw extractor. I’d advise against using a power drill for extraction, but some techs do, running the drill at slow speeds. Using an extractor to remove a stripped truss rod nut takes a lot of patience, but it’s doable. The trick is to be gentle but firm.
Installing the new truss rod nut.
This is the easy part. Just slide the nut onto the truss rod threads and turn it clockwise. Tighten the nut until it’s just a little snug. Tune the guitar up to pitch and check the relief in the neck. Depending on your playing style, .010" to .012" should be plenty of relief. Check out “Time for a Neck Adjustment?” if you’re not sure how to adjust the truss rod.
Averting disaster.
A stripped truss rod nut is bad news, but it can usually be replaced inexpensively. However, if you strip the threads or nut at the other end of the truss rod—where it screws into hardware embedded within the neck itself—that’s a different story. Also, if the exposed threads on a truss rod are stripped, a replacement nut will not help. In either case, the truss rod itself would need to be replaced—a very invasive and expensive repair. At that point you have to decide whether replacing the neck makes more sense than spending a fortune on major surgery. The bottom line is simple: When adjusting your truss rod, don’t over-tighten the nut.
If you’re not comfortable working with your truss rod nut, consult a qualified repair technician. Guitar techs and luthiers deal with these issues all the time, and paying them for their expertise can be a wise investment.
[Updated 1/25/22]