How to adjust the neck on a guitar

Truss rod adjustments can be a scary thing, especially when you’re new to the game.

A Les Paul leaning against the wall

Trust me, they’re not. Not if you know what you’re doing.

If your guitar is acting up, and doesn’t quite feel or sound the way it should, don’t worry. You’re about to get all the info you need to take matters into your own hands.

Time for a Neck Adjustment?

Before jumping in to any details, let’s first get our heads around the basics.

A truss rod is a metal bar that reinforces the neck, and is designed to counteract the tension of a guitar’s strings. It creates stability and makes it possible to adjust the curvature of the neck. If this tension isn’t checked once in a while, it can bow the neck.

There are two types of truss rods: single- action and double-action. Single action came first and has been around for while, whereas the double action design is quite modern. The difference between the two is that double action rods are threaded on both ends. And rather than one end being anchored in the wood, a double action design has two shafts anchored to each other. Threading both ends allows for the rod to move in two directions at once when the nut is tightened. This makes it quite stable, with low maintenance

Now, with that out of the way, let’s move on to the interesting stuff.

Primary signs that tell you your neck needs adjustment

Sooner or later, the neck will go out of adjustment on pretty much every guitar. Why might you ask? It usually has to do with weather, changes in humidity and altitude. Sometimes also after changing the gauge of your strings.

The first signs are usually fret buzz and bad intonation, but you can also tell something is off if you experience a change in the action of the guitar. Perhaps it’s a little higher and stiffer than normal? It could also be that you find dead notes on your fretboard all of a sudden.

Checking Neck Relief

So, if you suspect you have a slightly bowed neck, for whatever reason, what do you do next? There are two good ways to check what the exact problem is

How to Sight a Guitar Neck

Checking if guitar neck is bowed

To check if the neck on your guitar needs to be adjusted, start off by taking a good look. At this stage, you’re just trying to understand if the neck is straight or not.

Make sure it’s tuned to pitch, turn it on it’s side and look down the neck from the headstock to the bridge. Look at both sides of the guitar, the treble and bass side. Is it straight, or can you see a curve? If you’re a bit uncertain what to look for, don’t worry. If the neck isn’t straight it’s likely to have an upbow or backbow. An upbow is most likely caused by high string tension, where the string is too far from fret.  A backbow will be the opposite and is probably due to actual warping of the neck. Culprits already mentioned above

Checking Relief Using The Strings

Eyeballing the neck to look for a bow if you’re a beginner can sometimes be tricky. You may not trust your eyes or interpret what you see correctly. If you’re still a bit uncertain after having checked your guitar, there is another thing you can try.

Simply fret the string at the first fret (you can use a capo for this) and then depress the last fret. The string now serves as a straightedge. After that you put your finger on the 7th fret, and you look at the gap between the bottom of the string and the top of the 7th fret.

A large gap indicates an upbow which means the neck needs to be tightened. If it’s too tight or maybe no gap at all, then you’re dealing with a backbow, and you’ll need to loosen the tension in the neck.

How does it work?

By now you’ve realised that the problems you experienced are caused by a bowed neck. You have also noted whether you need to tighten or loosen the neck. Next, you need to get your tools out and get started.

Locating The Adjustment Nut

At The Headstock

The truss rod is either located on the headstock, behind the nut or at the end of the neck. In most guitars, especially the Gibson and Gretsch designs, the truss rod access is found on the headstock. It usually sits behind a cover that you can easily take off. This is ideal and makes the actual adjustment of the truss rod fairly straight forward, and you can do all the tweaking under tension.

Truss rod at headstock

At The Heel

On some Fender style guitars, and on many acoustics, the truss rod access is found at the end of the neck. With acoustics you can always reach through the sound hole, and it’s not too much of a problem. But, with electrics it gets a little more complicated, and often you’ll need to remove the neck altogether.

Truss rod at the heel

The tools you’ll need

  • Capo
  • Some truss rods require a screwdriver, flathead or phillips; others use an Allen wrench or even a socket wrench. Some guitars come with their own tool.
  • If you need to remove strings, maybe you’ll need a wire cutter

Which Way Do I Turn?

If you have an upbow you need to tighten the neck. Do this by turning the wrench/screwdriver clockwise, or to the right.

If you have a backbow you need to loosen the neck, and this is accomplished by turning counter clockwise, or to the left

Important to know is you should not adjust too much at once. Only make small adjustments, no more than ¼ of a turn at a time. Then you re-tune and check it again before continuing. How much you need to turn is different from one guitar to another, so doing a little at a time is a much better and safer approach.

Remember these tips

If your truss rod won’t turn, Do NOT force anything. It might mean that it’s maxed out and won’t go any further. If that’s the case, you need to take it to a luthier or a guitar tech.

Some necks won’t adjust right away. In fact, you might have to wait until the next day (or at least a few hours) before checking again, and making further adjustments. Just be patient.

Minor corrections are well within the scope of what you can do. Just know that if your neck has a severe bow, a truss rod adjustment is probably not the answer. Take your guitar to a qualified guitar tech.

Always use the correct size wrench or screwdriver. Remember, not all truss rods can be replaced.

Wrap up

As you can see, adjusting the truss rod is not as difficult as you might have thought. It’s just one of those things that we believe takes years of experience before we can do, and it’s simply not the case.

It’s also something that, if you check it once or twice a year, will render your guitar so much more playable.

Still not convinced you can do it? Don’t worry, the video below will put you at ease.

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