Everything you ever wanted to know about adjusting a guitar truss rod

There is tons of information out there on this particular subject, but nearly everyone explains how truss rods work the wrong way. This is my attempt to explain it the right way.

Oddly enough, this is my first article written here exclusively on truss rods. I will explain how they work in a moment, but first, a few facts.

This is lengthy, but worth the read, trust me on this one.

Fact: The vast majority of guitar players do not adjust their truss rods. Ever.

It can safely be said - and this is a raw guess but I'm pretty sure it's accurate - that about 1 out of every 25 electric guitars sold never have their truss rods adjusted after purchase.

Does this mean there is a very high chance any used guitar you buy will have a screwed up neck because of this? Yes.

With the exception of guitar shops that sell high-end gear where every guitar is set up by a tech before sale, any used guitar you buy is pretty much guaranteed to have a neck that has only had its rod adjusted once, and that was at the factory it was made in.

And yes, you can "save" a neck. I'll explain how later.

Fact: A properly adjusted truss rod NEVER guarantees a buzz-free guitar

A perfect example of this is the Fender Jazzmaster and Squier Jazzmaster. You could also count the Jaguar here, too. Never have I played a Jazz or a Jag that didn't buzz, even with a perfectly adjusted rod. Why? Because in the way the guitar is made, buzz is simply part of this particular guitar's character.

The only, and I mean only way to make a Jaguar or a Jazzmaster almost 100% buzz-free is to specifically use flatwound strings of 12-52 thickness or greater. What does this do to decrease fret buzz, specifically? Tighter tension. Flats are tighter at pitch compared to roundwound. You slap a set of 12-52 flats on a Jag or a Jazz, adjust the bridge, saddles and truss rod appropriately, and it will be the most buzz-free you've ever heard one of those guitars. Not absolutely buzz-free, but real, real close.

Fact: Some fretboards buzz more than others

The general rule of thumb here is that the rounder the board, the more fret buzz will happen, which is why Fender necks typically do buzz more than others.

Fender or Fender-style necks have the roundest fretboards. The modern radius Fender uses is 9.5-inch. Older vintage-style Fender fretboards use a very-round 7.25-inch. Gibson necks use a significantly flatter 12-inch fretboard radius. And these days there are also plenty of electrics out there with a super-flat fretboard radius of 14 or even 16-inch, even for cheap. Heck, the Jackson JS22 I just wrote about recently has a compound 12-to-16 inch radius fretboard, which you can get right now for a stupidly low price.

Your hand grabs around a rounder radius differently compared to a flatter one, and it's very possible that fret buzz happens because of the way your hand grabs a certain roundness of neck and/or fretboard.

What you can take from that is this: Try different guitars. Don't go all-Fender, all-Gibson or what-have-you. Just try different guitars with different types of neck thickness, fretboard radius and so on. Try cheap, try expensive, try them all. Eventually you will find one that buzzes least when your hands are on it.

Fact: Many players use picks that are way too stiff that causes buzzing everywhere

The pick I use these days is a Fender 351 medium; I started using these shortly after I bought a Jazzmaster. Back when I played nothing but Strats, I used a significantly thicker and stiffer Dunlop Tortex .88mm. And while that certainly isn't the thickest pick out there, it is fairly chunky compared to a Fender 351 medium.

I watch guitar videos on YouTube routinely. I'll see some guy demonstrating a new guitar, and he's wailing away on it. When he hits the strings, I can easily hear the guitar go out-of-tune on almost every pick strike because he is banging the strings with a thick pick. He's playing way too hard, and, surprise surprise, causing fret buzz. Again, bear in mind he's playing a new guitar that has most likely been set up properly. But that doesn't matter for much since he's playing like an idiot and banging the strings as if he were an ogre swinging a club.

Stop banging on strings like a fool, and watch how much your fret buzz decreases. Night and day difference.

If you must use a hard/thick pick because you feel it works best, consider using one with very defined point. How to find them? Jazz guitar picks. There are many available. Try a few. It might feel weird at first, but that pointier pick will prevent you from banging strings too hard like an idiot.

What is the point of adjusting a truss rod?

To decrease fret buzz.

However, I mentioned all of the above because there are many who think that adjusting a truss rod cures all fret buzz problems. It does not. There are other factors, such as string used, pick used, how your hand grabs a neck of specific thickness and roundness, and so on.

At this point you know that roundwound strings, which nearly everyone uses, including myself, buzz more than flatwounds do. You also know that hard strikes on strings using thick picks will cause more fret buzz.

Now we go on to the next point, neck bow.

The debate over the proper bow of the neck

Some believe that the guitar neck should be absolutely as flat as possible. Others believe the neck should have a slight bow to it.

I am of the latter belief. I believe that a wooden neck on an electric guitar should have a slight bow to it, otherwise known as relief. Why? To accommodate for climate change when it happens. Humidity, specifically.

A neck that has its rod adjusted to have slight front bow allows it to naturally flex forward or backward depending on the humidity in the air while still remaining relatively buzz-free.

A neck that is adjusted totally flat will have days when it buzzes all over the place. If a wooden neck is set flat with no bow, that means there will be days when the humidity will change and the neck will bow back, resulting in a buzzy nightmare when the guitar is played.

Yes, it is true that a slightly-bowed neck is a tad more difficult to play because you have to press a little harder with your fingers to fret notes. But that's what lighter gauge string is for.

The debate over how much space should exist from fret-to-string

To test the space from fret-to-string, this is how it's done.

1. While holding the guitar in the seated position, on the 6 string (the "low E"), fret and hold fret 1. Alternatively, you can put a capo on the first fret to make this easier.

2. Fret and hold the last fret with your hand, which will either be fret 21, 22, 23 or 24, depending on how many frets your guitar has.

3. While having fret 1 and the last fret held down, look down at the neck and tap the 12th fret. Some say to tap the 15th or 17th fret. I say tap the 12th because it works for me.

You tap the 12th so you can examine the amount of space the 6 string has from string-to-fret.

Very important note: Don't look down at the neck at an angle like you would as if you were playing the guitar. Look at the neck straight up-to-down, meaning that when looking at the neck, you should only see the edge of the fret and maybe just the beginning of the fret length, and no more than that.

Now from here, it's the amount of space that sparks the debate.

Some believe amount of space from string-to-fret here should be enough to fit a razor blade or a credit card under that 6 string. Others believe it the space should be just wide enough to slide an American quarter coin under the string.

Which is correct? All of them and none of them, because ultimately it depends on what you feel is correct for your fret hand when playing.

If you have absolutely no idea which is right for you, use a quarter or credit card or whatever you have handy. I suggest use of the quarter coin because a credit card has raised text and numbers on it that can screw up your measurement.

How to adjust a guitar truss rod

Okay, here's how you do it.

First, look above at my 1-2-3 steps and follow those.

If on the 12th fret you have the proper space from string-to-fret, leave it alone.

If on top of the 12th fret you see absolutely no movement, as in no "bounce" and the string is touching the 12th fret no matter what, the truss rod needs loosening.

If on the 12th fret there is a lot of space between the string and the fret, as in higher than the size of an American quarter, the truss rod needs tightening.

How to tell which way tightens and which way loosens?

Clockwise a.k.a. "turning right" is tightening.

Counterclockwise a.k.a. "turning left" is loosening.

Both of these are true whether you have a headstock positioned truss rod hole or a heel positioned truss rod hole.

How much turn should you use when adjusting a truss rod?

1/8 turn at a time, with wait periods in between.

A safe waiting period is 24 hours to allow the wood time to settle. It's up to you whether you want to wait or not.

How should you test a truss rod adjustment?

Only test the adjustment with ALL the strings tuned to pitch. Some make the classic mistake of loosening a few strings to get to the truss rod adjustment hole, then test the bow without tightening those strings back up first. DON'T do that, because with strings loosened, string pressure is lost and you won't get an accurate test.

Yes, this adds time to the overall process, but it has to be done that way. Keep in mind you originally found the bow out-of-alignment with your strings all tuned to pitch to begin with. You will need to test your adjustment the same way.

Also, and this should go without saying, test your bow with the guitar in the seated position, as that is how you play it most often. String pressure changes depending on how you hold the guitar.

Does this mean if you play your guitar standing most often that you should test your bow that way? Yes, it does. You test the bow in the playing position you use most.

Will you have to adjust your truss rod if you change string gauge?

YES.

If you switch from 9-42 to 10-46 or vice versa, the bow of your neck will change slightly and you will probably have to crank the rod either a slight turn to adjust. How much you have to make a turn depends on how thicker or thinner the strings are that you installed on the neck.

Will you have to adjust your truss rod if you change string type?

Maybe.

Hex-core strings, like D'Addario brand, are stiffer at pitch compared to those that are round-core, such as DR brand.

While the gauge/thickness of the strings between string material types may be the same, the stiffness at pitch is not. Sometimes you will see no change in the bow between hex to round, and sometimes you do.

If you do notice a change, it won't be drastic. Well, not unless you install flatwounds, in which case you probably would see a significant change in the bow due to the significantly higher tension of flats.

Is the lowest possible action always the best?

ABSOLUTELY FRICKIN' NOT.

Part of adjusting the truss rod may be to achieve the lowest possible action, which means to get the strings as close to the frets as possible without buzzing.

Bad idea.

Why is it a bad idea? Because that kind of action actually works against you when playing chords. Specifically, it will make your fingers hurt, possibly even to the point of hand injury.

Now granted, if you've got one of those "metal" guitars with a super-thin neck with super-jumbo frets with a super-flat fretboard radius, then sure, go low and stay low, because that neck is suited for that.

For pretty much every other type of guitar neck out there, super-low-action sucks because all you feel are the strings "biting" into your fret hand. Forget about bending notes because it will be painful. Even something as simple as basic string vibrato can be a painful experience when the strings are set too darned low.

Super-low-action is absolutely not suited to every electric guitar. It is totally okay to have strings that aren't super-low.

"I followed some instructions elsewhere and my guitar is set up totally 'correct', but it now it feels awful since I followed those instructions."

If you don't feel totally comfortable with the way your guitar action is set up for any reason, you're doing it wrong.

Ultimately, when you set up a guitar, be it for truss rod, bridge height, saddle height and so on, you set it up for you. And you may find that how you set up a guitar disagrees with what is "normal." THAT IS OKAY. Set your guitar up to be most comfortable for your hands only. It is your guitar, you set it up, you make it comfortable. You are the guy playing it. Remember that.

What about twisted necks?

Know that this is also known as a warped neck.

Short answer:

There's nothing you can do about a twisted neck unless you're willing to dump a whole bunch of money into a repair. And I do not recommend attempting to fix it yourself.

Long answer:

A twisted neck is where even after a truss rod is properly aligned, the neck is twisted to where some strings show proper space on a bow test where others do not. The neck has literally developed a twisted shape, so no amount of adjusting the truss rod will ever completely fix the issue.

My opinion on the matter is that it's not worth your time to fix this. When a neck decides to twist, I'd say hand it to a luthier and pay him a bunch of money to attempt to straighten it out again. If the guitar you have is something where you think it's worth it, pay the man and hope for the best. Otherwise, junk it and get another guitar. Or at least another guitar neck.

Can you "save" a guitar neck?

Yes, provided it's not twisted.

Let's say you pick up an old electric guitar. And by old I mean something built at least 20 years ago.

Now it's probably true the truss rod was never adjusted after it left the factory, and it's probably also true the neck will have a serious bow to it that needs adjusting.

On the first crank of that rod, you will hear a CRACK that will send a chill down your spine. Having a neck sit for 20 years will make that happen. The wood has settled so much to the point where it will "take some English" to even turn that rod. When it finally turns, that first turn will make an ungodly sound, almost as if you snapped the neck.

If all goes well, you give the rod maybe a 1/8 or 1/4 turn at the most, then let the wood settle for a day and go back to it tomorrow. Little by little, day after day, you will be able to continue turning it until you get bow set properly again.

Yes, this is a long process and may possibly take up to a week just to get it done. But if you're patient, you should be able to save that neck and have a playable instrument. After that, with normal guitar play, the wood in the neck should adjust just fine.

This is, by the way, why it's better to buy a vintage guitar that was actually used regularly. A guitar is a machine, and for a machine to continue to work, it must be used. Let the machine sit too long, and it will end up in disaster on attempt to use it again.

I'm not saying not to buy vintage. Just be mindful of that neck.

Published 2015 Aug 7