Action Neck Bow And Your Truss-Rod

I am going to start this by stating a central point of this tutorial. The Truss Rod’s Primary Function Is Not To Ajust Your Action!!

It is not a magic wand that changes your action. Thinking this and acting upon if can really screw up your guitar. Clear? Then I shall proceed.

Before you touch your truss you need to know the basics of doing so and what exactly it is. A truss is in essence a metal rod anchored at either end of the neck inside a solid metal housing so when you tighten the rod the it pulls on either end of your neck. This in turn reduces the amount that the neck bends (or bows). If you loosen the rod on the other hand then the rod loosens and does not pull on the neck to straighten it thereby increasing bow. (NB there are some trusses that operate in the opposite direction as well.)

The truss is an integral part of any steel strung guitar (with one or two exceptions eg Steinbergers, Vigier's and Klein, without it the neck would either snap or be badly warped very fast. Its main function is to prevent this by counteracting the pull of the strings, which bends the neck. The most common misconception is that it will adjust your action. To some degree this is true however it changes the action by changing the curvature of the neck not by raising or lowering the strings. For example in a bowed neck the action will be low at the top and bottom frets but high in the middle, to visualize this think of it side on with the string underneath the neck. The string is like a flat piece of ground with the neck forming a low arch over it. The angle of bow is known as the neck’s “relief”.

Relief is measured at the 7th fret when both the first and last frets are pressed. The gap between the low/high E string and the top of the 7th fret is the amount of relief. This can be measured with a feeler gauge, but if you are cheap (let's face it who isn’t?) You can buy very thin picks and use those to measure the relief height. The height that it “should” be can vary quite a bit, between 0.004” and 0.012” for guitars is about average (that’s 0.1mm to 0.3mm) these can be adjusted to taste however (BB King has a much larger relief than that and Allan Holdsworth has no relief.) For basses 0.008” to 0.018” (0.2mm to 0.4 or 0.5mm.)

When the neck is flat on the other hand this instead forms two parallel lines, this is for many people the ideal since it allows you to get the action as low as possible all the way up the neck. However this has it’s draw back as it can cause the strings to buzz so get as close to parallel as you can without string buzz. Sadly the ideal parallel lines are rather hard to achieve due to the fact that when your strings vibrate they vibrate in an elliptical shape with the most movement in the middle (12th fret), which means that usually some bow is necessary. Also continuing to tighten a truss rod after the neck is dead flat serves no purpose as the instrument will simply buzz as the strings vibrate against the hump in the center of the board that has been created by back bowing the neck. However after any kind of adjustment of this sort you need to re-intonate or no matter how carefully you tune your guitar it will sound wrong (acoustics being the exception).

The truss can to some extent also be used in copying anther person’s tone, if you have it set similar to SRV with a reasonably large amount of bow, then it will give a very clear note and help you nearer to his crisp tone. If on the other hand you want say Kirk Hammet or Vai-esque tone then you need it as low as possible, the notes will not ring clear as much but their easier to play.

Finally adjusting it. This is something you need to be careful when doing as not taking care can actually damage or even snap the neck (not what we want!). But as long as you follow a few simple rules you should be absolutely fine.

01. Before you even touch your guitar make sure you have the right tools that fit into the adjustment nut. Martins and many other acoustic guitars with truss rod nuts beneath the f/b extension use a 5mm allen head wrench. Gibsons and others with a larger acorn style nut at the peghead use a 5/16" nut socket. Taylor uses a smaller 1/4" nut socket. Many Fender Electrics use a 1/8" allen head wrench. If you don’t you will damage the nut and could render future adjustments impossible.

02. Make two marks, one on the truss and one on the guitar (pencil or similar) that line up so you can tell how far it’s moved and if necessary return it to the way it was.

03. Never Ever move it more that an 8th of a turn at once, I’ll repeated that to make absolutely sure you’ve got it, Never Ever move it more that an 8th of a turn at once. This is because a small adjustment will go a long way with this you won’t be spinning it round and round like a wing nut, if you do your neck will snap and hopefully hit you in the face for being a moron.

04. Always start by loosening the nut first. If it is already as tight as it will go and you try to tighten it some more...crack! See ya truss rod, hello heartbreak.

05. Adjustments are made with the instrument strung and tuned up (how can you tell what it needs when it’s got no strings bowing the neck eh?) you also hold it how you would if you were playing because believe it or not this actually can make a difference to the neck. (NB some guitars require you to slack off the D and G strings loosened to fit the Key in however after the adjustment tighten them up again. Also some guitars require you to remove the neck completely to access the truss rod (eg telecasters)

06. Check the neck’s relief (bow) after each adjustment using the string method further up.

07. If it really doesn’t want to move or you think something not right take it to a shop. A truss adjustment isn’t expensive at all and will take ten minutes max. And hey if they **** it up then you get a free guitar!

Hope this has been of some use to you and good luck.

Special thanks to Power freak since I borrowed paragraph 4 from his GB&C FAQ.

Comments

[ekune26]

cool thing dude...

[orion_rider]

pretty cool useful stuff i didnt know before

[vinniebeast]

Good information, one of the few articles that actually told me something I didn't know before!

[the_cheaptrick]

oops. i voted 1 star by accident

[Four Symbols]

nice... sounds like a good free guitar scam

[FacingUsAll]

03. Never Ever move it more that an 8th of a turn at once, I?ll repeated that to make absolutely sure you?ve got it, Never Ever move it more that an 8th of a turn at once. This is because a small adjustment will go a long way with this you won?t be spinning it round and round like a wing nut, if you do your neck will snap and hopefully hit you in the face for being a moron.

5 Stars for that last line

[EZLN libertad]

finally there arent some jackasses that will put me down for having questions about truss rods...

5

[Erc]

very good article.

[Sun of a Studio]

Yeah where was this article 3 months ago when I was trying to find a way to correct my bowing neck? Luckily I fixed the problem but still. Good job, 5 stars.

[PumpkinsPunk]

I have a big truss

[wangtangkiki]

03. Never Ever move it more that an 8th of a turn at once, I?ll repeated that to make absolutely sure you?ve got it, Never Ever move it more that an 8th of a turn at once. This is because a small adjustment will go a long way with this you won?t be spinning it round and round like a wing nut, if you do your neck will snap and hopefully hit you in the face for being a moron.


5 Stars for that last line

Agreed.

[iain4444]

Thanks man, I know my Cort acoustic needs this. You said you need to reset the intination after doing it, but acoustics are the execption, so after I, or someone does it for me, i don't have to worry about my intination being different at all?

nope because you can't ajust it on achoustics because the bridge is built differently

[mesaboogieman]

sillybuuger12: cool article thanks dude

[bmartinak]

Interesting article, but after playing the guitar for more than thirty years, I felt I had to add this bit of advice: don't mess with the truss rod at all. Have a qualified professional do any such adjustments for you. Trust me on this one. It isn't like changing strings. One false move and your guitar could be trashed. Better safe than sorry.

a fair comment, however there will always be those who insist on doing it themselves and i thought they had best know how, also i do mention the fact that if they are in any way unsure of what they are doing they should take it to a pro.

[knoob]

Thanks! I felt that my fender acoutic needed this. I'll probably gonna give you five stars for that neck-snapping part

[IamJonsCranium]

bmartinak:
Interesting article, but after playing the guitar for more than thirty years, I felt I had to add this bit of advice: don't mess with the truss rod at all. Have a qualified professional do any such adjustments for you. Trust me on this one. It isn't like changing strings. One false move and your guitar could be trashed. Better safe than sorry.

how do you trash a guitar changing the strings. i find that if you know what the truss rod does, it should be a fairly simple thing. a neck can bend a bit before being ruined, so if you want less bow and you turn the nut and get more bow, then you are going the wrong way. 'is simpo!'

PumpkinsPunk:
I have a big truss

my truss is bigger than yours. i guess you could call it a bass truss.

[IamJonsCranium]

and i should add, its about time you (or anyone) did this article. 5*'s

[gmsje]

5 stars. Now I know why I have always been told not to touch the truss rod. I'm still rolling over laughing about the moron line too.

[Sun of a Studio]

bmartinak:
Interesting article, but after playing the guitar for more than thirty years, I felt I had to add this bit of advice: don't mess with the truss rod at all. Have a qualified professional do any such adjustments for you. Trust me on this one. It isn't like changing strings. One false move and your guitar could be trashed. Better safe than sorry.

I don't agree. I think if you are to own something, you should know how to fix it. Plus not all of us have the money for an adjustment every season. I usually do but I don't take it some place I just do it myself. If you can't fix your guitar when it's broken then what're you going to do when something goes wrong in the middle of no where. Of course electric guitars don't usually work in the middle of no where since they would lack electricity but acoustic guitars have truss rods too. It's better to know what you're doing then bring your guitar in like a child bringing a note to his parents so they can read it to him everytime. You have to learn eventually.

[weird hippie]

kinda get it...(i'm such an idiot)

[weird hippie]

not sure if that word is a bad one (the last one)my bad if it is.

[cold_static544]

despite this great article, i would still send my guitar to the shop if the truss rod needed adjustments.

: )

[Spydr]

How do u adjust intination?

[RedburN]

Interesting, I'm still a little affraid to mess the whole thing up :P

[AimlessAmoeba]

yeahhh... wish this would've been on here a month ago

[LochieW]

Awesome, now I acctaully know what a truss rod is.

[Towlie]

I thought truss rods were there for adjusting intonation...

you thought very very wrongly then

[GuitaPlaya]

what the hell is s/he talking about

[Mr_Die_Easy]

very accurated

[greeneggs'n'ham]

what the hell is s/he talking about

exactly. (well written, though. dig the moron line.)

I've been playing for a while and i haven't ran into any problems with mine. I really don't see much of a necessity to mess with it.
Plus, the way it sounds, i wouldn't screw around with mine. After all, a repair shop bill can't possibly cost as much as a new guitar.

[greeneggs'n'ham]

^5 stars nonetheless. just for sheer effort.

[Blackbullet]

good stuff.

[evening_crow]

Spydr:
How do u adjust intination?

ok, to adjust intonation:
Place your finger on the string at the 12th fret and play it to hear a harmonic note (do not press the string down to the fret, just touch it). Then, play the string at the 12th fret (press down the string to actually play the note). Both notes should sound the same, if not, then you have to adjust the lenght of the string on the guitar's bridge. On the bridge you'll find some screws that move the piece where the string goes over (every string has an independent piece & screw). If the freted note is higher than the harmonic note, turn the screw to the left to make the length of the string longer (this will make the harmonic note higher). If the freted note is lower, turn the screw to the right side to make the length shorter (this will make the harmonic note lower). Just keep on doing this until you get the same note.

[Wickerman_18]

which strings make the loudest sound

[Smokey Amp]

Fantastic Article. 5 stars.

Also, thanks Evening_Crow for the intonation lesson, I never knew that...

[Smokey Amp]

Fantastic Atricle. 5 Stars.

Also, thanks Evening_Crow for the intonation lesson, I never knew that...

[Blade1096]

Very good article. And as far as snappin the neck goes.....if you actually put that much force on it to accomplish that....the moron common fits very well lol. It would take a pretty good amount of force to do that. Did anyone mention backing off the screws on the back of the neck where it attaches to the body to settle the neck?

[Blade1096]

What I meant by settling the neck is loosening the screws on the back of the guitar body that attach the neck to the body. You don't have to back them off much...just enough so that you hear the neck make a slight ....well creaking noise is the best way i know to explain it. Then re-tighten the screws. This settles the neck into the body. Correct me if im wrong please but after adjusting the neck arent you supposed to do this?

[THE GRIM ROCKER]

good article, nice depth, but i dozed off half way through..still good though, well done.

[Bassist TorViK]

gotta question... I was adjusting the truss rod on my bass a few days ago, but I had heard you couldnt turn it more than 1/4 of a turn. also, I thought it was naturally normal for it to be hard to turn, so I really applied a lot of force, so it turned a little, but I heard a SNAP... It didnt break the neck though, and it still plays OK... so what the hell do you think happened ?.... is it dead or what ?

[Abyssal]

If you heard a snap, something broke, simple. What it is that broke, maybe your truss rod?

you've snapped your truss

[Metallica12_12]

LOL you snapped ur truss for sure lol... haha i member when one guy was doing it and he snapped the neck HAHAH.
But it should be ok, if u can get it replaced. casue ur neck is probly about to start bending like the peice of shit you have now made.

it's going to be VERY expensive to have done so unles it's a very expensive guitar your better of changing the neck or binning the whoole lot and getting a new one

[crazynickman]

wow no flaming at all...5 stars, informative n stuff. i would be the moron who gets hit in the face with my neck tho so i've taken it to the store for that. i dont trust myself

[leavink]

http://www.fretnotguitarrepair.com/trussrods.htm
nice copy(unless you own or are a webmaster at fretnoguitarrepair.com)

[touch_me_im_sic]

well rote

[BrianApocalypse]

my neck is pretty weird. The left side of the fretboard has some relief but the right (high E side) doesn't.

I hope it isn't broken...

[BrianApocalypse]

I also think that the ruler measurement at the 12th fret thing is crap and confusing. It is better to look down from the headstock onto the bridge to look for significant bends.

[xtremedrummer49]

you have truly just made my day.... i had an appointment with my tech set for tuesday to fix my truss...but i did it myself (with your help)

kudos

[acoustix70]

very informative...

[MetallicaNRoses]

good... but i always thought i was the eigth fret that you measured the relief on...
oh well

[RustyGold]

Very helpful. 10/10

MetallicaNRoses
wrote:

good... but i always thought i was the eigth fret that you measured the relief on...
oh well

actually ur looking at the halfway point between the first and the fret closest to the neck body joint.

7-8th fret.

[snakeyes9510]

should you take your strings off to tighten/loosen the truss rod?

[tiv0]

thanks man
helped lots
im not an ignorant person when it comes to working on basses/guitars but this was one thing i always had a little trouble with

[WickedBeast666]

is it bad that my relif for my low E (6) is less then 1mm, and the relif for the high E (1) is even lesser? I do get some fret buzz on my guitar, but I don't belive i'm going to tuch the truss

[TripleN666]

Very nice article, it really saved my guitar and finally i know how to do it right.
5*

[JPageZeppelin]

wangtangkiki wrote:

03. Never Ever move it more that an 8th of a turn at once, I?ll repeated that to make absolutely sure you?ve got it, Never Ever move it more that an 8th of a turn at once. This is because a small adjustment will go a long way with this you won?t be spinning it round and round like a wing nut, if you do your neck will snap and hopefully hit you in the face for being a moron.


5 Stars for that last line


Agreed.

me too lol

[acid eaters]

if u have a truss rod in a broken guitar neck and it's not damaged could u take it out and put into another neck?

[luca_turichi]

Hey, cool article, i actually have been adjusting truss of many guitars since the last 2 years, and actually one of them is useless now (my oe-40) i think i should stop doing it... thanx for the info!