How to Repair a Guitar Nut
Improved sound, playability and intonation are all benefits of a properly cut, well fitted guitar nut. String height, spacing and nut material all play important roles in producing a nut that, together with a good setup, will allow the instrument to perform at it's peak.
This page contains tips and techniques on how to repair a guitar nut that has relatively minor flaws, wear or damage. We'll focus on economical ways of maintaining an original part to get it back in working order, plus look methods used when the damage starts to become more involved. Use these quick links to jump to the two major sections: how to repair an existing nut and how to properly remove an old nut.
Table of Contents:
- Refitting A Loose Guitar Nut
- Dealing with Excess Material
- Repairing Worn Slots
- Re-Cutting a Nut
- Repairing Minor Cosmetic Damage
- How to Properly Remove an Old or Damaged Nut
- Splitting A Nut For Removal
- Cleaning The Nut Slot
- Shimming A Guitar Nut
In contrast, the decision to fully replace an existing nut depends on many factors and requires a different process. Therefor, installing a new nut is covered in more detail in related articles. But with a little patience and the right tools, you'll be able to repair or replace a guitar nut like a pro!
Please understand this material is for those who consider themselves handy and are interested in learning more about the next level of maintenance of their instrument. If you don't have any previous experience with this type of work, get yourself a cheap guitar you can experiment on until you gain confidence in your own skills, and leave your favorite prized axe in the care of a qualified guitar tech. (Note to novices: my own ' 70's U.S. Strat would be worth a heck of a lot more money today if I hadn't "tinkered" with it years ago.)
IMPORTANT!: Before doing any work on an instrument, make sure the guitar is situated on a stable bench of some sort with appropriate support and padding, and under lots of light.
Refitting A Loose Guitar Nut
First, remove the strings or position them out of the way to provide free access to the nut area. Make sure the nut is securely in place to begin with. If it isn't, gently pull it out, clean off any excess glue and try dry-fitting the nut to see if lines up properly or not. You might find the nut centers nicely - that's a good thing. At this point you can put a couple of small drops of Titebond, Krazy Glue (if you want it done quick) or a decent quality wood glue on the bottom and reset it. Replace the strings and snug them up to apply pressure and give the glue a chance to set - anywhere from 30 minutes to a couple of hours.
Due to seasonal changes and wood tending to dry out, even the best guitars, both acoustic and electric, can suffer from a "slipped nut". It's a very common occurrence and also one of the easiest to fix.
Dealing with Excess Material
Flaws. Overhangs, excessive top material and sharp edges are usually cosmetic in nature and fairly easy to remedy.
If the nut has excess material sticking out each side and is solidly in place to begin with, it's best not to try and remove it unless it's absolutely necessary. Mask around the nut using a low-tack masking or painter's tape to prevent damage to the surrounding area. Use a small, fine-cutting file and carefully remove excess material - using upward strokes from the bottom of the nut to the top, away from the neck - until the nut ends are flush with the neck surface. Check your work often. Some types of cheap soft plastic nuts can cut very quickly compared to other harder nut materials such as bone or Tusq. If you're not careful, you can wind up scratching or gouging the neck finish.
Excessive top material can feel uncomfortable especially around the edges. You can use a flat file that's a little more course, or a sanding block with 200 grit sandpaper to bring the material down to an acceptable level. Be cautious of the surrounding area, make sure it's masked off - one bad slip and you're into neck refinishing.
Without getting into exact string height just yet, let's say an acceptable level is when there's a little room, say the width of a plain G string, from the top of the string in the slot to the top of the nut.
Next, with your fine file, trim up the corners at each side of the fretboard so they're smooth with the curve of the neck. To finish up and remove any scratches from rough filing, polish the nut starting with 400, then 600, and lastly 1000 grit sandpapers. Sand lightly around the corners to smooth uncomfortable sharp edges. Remember, different materials produce different results so take it easy.
Repairing Worn Slots
Wear. As guitar nuts age, they can feel quite comfortable but the slots can become low enough to cause an irritating buzz on the open strings and produce a loss in tone. It's pretty easy to determine which ones are the culprits, they're the ones that buzz when you give them a good open pluck and sometimes you can actually see them riding the first fret. Usually it's only one or two strings which show these symptoms and to keep things simple, we'll deal with rebuilding string height on a limited level.
A standard remedy for this problem is to use Krazy Glue and baking soda. The recipe works fine, but I'm a fan of using the same material the nut is made of. I keep a handy supply of bone dust available as it tends to cover most instances of string slot repairs nicely. We'll also need something to cut the slots with. A good set of nut files will go a long way, but a fine-toothed hacksaw blade ground down to the right thickness will do, as will an X-acto sawblade. For a more comprehensive list of guitar setup tools check out our guide here.
After identifying the bad string slots, get the strings out of the way and mask off the work area. Using one of the fine cutting blades, carefully clean out the old slots to expose new material.
Have a small flat-bladed tool like a screwdriver handy, and all the other materials you'll need laid out for quick access.
PRO TIP: Keep a small jewellers screwdriver ground down to a nice point on the business end, this makes a great awl for lots of small tasks around the guitar in general. For nut slot repair, use the sharp tip to "prime" the bottom of the nut slot by pushing it into the slot at three or four points along it's width. This helps the new material grip the bottom of the nut slot and resist breaking free prematurely.
Put a tiny drop of Krazy Glue in the freshly cleaned slot, careful not to let it run. Immediately scoop up a fair bit of filler material and drop it in the glue. Compact it into the glue by rolling the shaft of the small screwdriver in the slot - try to work quickly because this stuff sets up fast! Follow the same procedure for each worn slot. Give the filler a couple of minutes to set up then carefully remove any excess material from the top surfaces by either filing or scraping it away.
Now that you've got a newly rebuilt nut-slot, it's time to cut it to the right depth.
Re-Cutting a Guitar Nut
There are lots of ways to re-cut a guitar nut and it can be a little tricky. The most important thing to remember is if you go too low, you'll have to start over. I've developed my own particular ways of determining when the slots are deep enough through years of experience. You can find more detailed information on cutting a nut on the How To Set Up A Guitar page, and in other articles on the site.
After the slot's been filled you should be able to see where it originally was through minor color variations.
Take your slot cutting tool and make sure there's at least enough of a groove to grab the string tuned near to pitch. Loosen the string off a bit and move it out of the way. Carefully work the slot deeper until the string, near pitch again, seems to be sitting at the right level. This is really going to be a matter of feel or intuition for now until you gain a little more experience and information. When you're satisfied with the results, polish up the nut, put a little bit of Teflon oil or pencil lead in the slots for lubrication, tune the instrument up to pitch and away you go!
Repairing Minor Cosmetic Damage
Cosmetic damage is more unsightly than anything else. Small chips that don't affect the integrity of the nut aren't much of a problem. Whereas cracks, severe chips and missing chunks will warrant a total replacement. If the nut isn't structurally sound, it must be replaced.
Minor chips can be filled and buffed out using the methods described in this section. And please remember to mask off the area around the damage.
Using a similarly colored filler material, build up the damaged area using successive applications of glue and filler until the material is slightly above the contour you want to recreate. Level it out with a fine file and polish it up. You might find small pits and or discoloration when your finished but at least the nut is uniform again - and it's a relatively fast, economic alternative to installing a new one!
How to Properly Remove an Old or Damaged Guitar Nut.
Time, wear and tear and unfortunate happenings can warrant a guitar nut replacement. Once you're sure it's time to remove an old or damaged nut, well... it has to come out! It can be as easy as a simple tap or rather like pulling a tooth - Nurse?... pliers and a crowbar please.
In a best case scenario, the nut's already loose or just sitting cleanly in a right angle slot with no back edge.
If there's finish on and around it, take a sharp knife and score all around the edges to avoid chipping. On some older necks with maple fingerboards you'll see the finish, usually yellowed, layered on pretty thick. Be very careful around the finish, too much pressure can induce chipping particularly on vintage instruments.
It's also good practice to score along the back edge of the nut. The key here is to break the surface tension of any finish that might be attached to the nut itself.
Typical Fender and Gibson style nuts sit in a square u-shaped slot requiring a little more care and patience in removal. The same principals apply in protecting the finish as above.
Many other types of guitars, acoustic and electric, North American and offshore, have nuts that sit in a simple right angled shelf. These tend to be the easiest to remove.
Right Angled Nuts
To get the job done, you'll need some tools to extract the nut: larger screwdrivers and a pair of end nippers.
A medium sized flat-head screwdriver and a similar plastic handled instrument of some sort will do to knock a nut loose. Rather than using a hammer, these lighter tools will provide a little more control over the force applied to the nut.
Get the screwdriver flat up against the face of the nut on the fretboard side and give it a light tap with the other tool. If you're lucky the nut will pop right out. If not, give it a couple more light taps.
I have to stress this because you could wind up tearing out some of the wood underneath or behind it creating a nasty problem and extra repair work.
Sometimes well-fitted original nuts can be tough to remove, it pays to be patient - and careful.
With a few taps from either side, you should be able to see the nut shift slightly when it's loose. If it's really being stubborn and will not come out freely, use the end nippers to carefully try to pull it up and out of the slot; grip the nut at it's mid point and gently rock it back and forth while pulling upward.
Splitting A Nut For Removal
On some Fender type instruments with thin nuts, none of these efforts may seem to work so we'll try a different approach. Use a fine saw such as an Exacto Precision Saw or a Japanese Razor Saw and carefully cut the nut in half along it's length, then collapse it in upon itself by squeezing the two halves together. Of course this technique totally destroys the nut. Be sure to keep the fragments to help determine the original string spacing later on.
Cleaning The Slot
There are some fine specialty tools available from various suppliers for cleaning and squaring up the nut slot, but the same job can be done quite easily with some basic tools at hand. A sharp 1/4" chisel and a small mill file will do fine. You can use the chisel to scrape off any leftover glue and the file to square up the slot. Be careful when filing not to oversize the slot or create an uneven width from one side of the fretboard to the other. A good set of needle files will also help square up the surfaces and get tight into the right angles.
TIP: You can grind down the tang end of the mill file to create a chisel point - one tool two jobs!
As a final comment, the intention of this page is to give do-it-yourselfers a kick-start in basic guitar repair. If you're not 100 percent confident in your abilities, or are concerned about wrecking a prized possession, play it safe and take your instrument to your local guitar tech.
Shimming A Guitar Nut
When done properly, shimming a guitar nut can extend the life of an original guitar part dramatically.
The first step is to determine what thickness and type of material to use. Relatively thin cardboard makes an excellent shim material when treated properly. It's an extremely common product making it very easy to select something with the right base color and thickness. Plastic materials will work just as well, but they tend to be a bit too thick and harder to find in the right shade.
By saturating a piece of cardboard with Krazy Glue beforehand, you can essentially create a piece of plasticized material to work with that will do the job just fine. Look for something in the range of .015 to .020 inches, the equivalent of a medium G string on an electric guitar. It might not seem like a great thickness, but a little goes a long way as most shim jobs tend to require a marginal height adjustment.
Let's assume you already have the nut extracted and any remaining old adhesive has been removed. The mating surfaces on the guitar should also be cleaned of debris and trued up. It's imperative to note that in order to achieve a good, solid shimmed nut, all elements must rely on thoroughly cleaned and prepare surfaces.
Scuff the bottom of the nut with sandpaper or a file to prep the surface. Set the nut on top of your selected shim stock to check for relative position, in other words make sure you have enough material to work with and anticipate positioning. Apply a couple of drops of Krazy Glue to the bottom of the nut, then stick it to the shim material holding it firmly in place for a few seconds until the glue sets.
Once the glue has hardened, take a sharp knife or tool of your choice and carefully remove the excess material that doesn't constitute the new base of the nut. Trim up the surfaces with a fine file or fine sandpaper and you should have a rejuvenated nut worthy of a few more years of use.
The only thing left to do now is check for fit and glue the nut back in place.