How Do You Know If You Acquired A Guitar With A Broken Truss Rod?

[Johnny Two Tone]

Hello. I'm curious to know if their are any straight forward, simple ways to tell if your truss rod is broken (I said from 'a guitar you acquired' in the title because I'm not talking about snapping it when you're making an adjustment). Does the rod move loosely in the neck or anything like that?

 

I recently bought a Jackson USA SLS and I'm setting it up but I've turned the truss rod quiet a lot (a lot for a truss rod that is - it hasn't been turned all the way around or anything) and it's not really doing a whole lot to straighten the neck. The rod is nice and tight (feels like other truss rods I've adjusted), it feels fine while turning it, I KNOW I didn't do anything to it so that's not the issue. Oh, and I've certainly never forced anything.

 

I'm only asking so I can be aware of how much turning may be required - the neck was pretty bowed forward, so maybe the rod simply needs more turning than usual. It is less bowed now than before so that should indicate a working truss rod.

 

How far can a truss rod go (around) before you know somethings up? Thanks!

[bluelegacy]

I'm not an expert, but I'd agree with the statement that if the rod feels normal when turning (not too tight/loose) and you're seeing changes in the relief that it's fine. When I adjust truss rods I do it very slowly to let the neck adjust. I'm sure I'm overly cautious, but I give it hours for decent adjustments. How much relief is there now and what was it when you started? What is the goal?

 

Here's a good read if you haven't seen it Article on truss rods at Fret Not

[dewees]

The only broken truss rod I've encountered was obviously broken - It just spun around loosely when you turned it. There was no tension on it at all.

 

I have had guitars that required more than a full turn on the truss rod - Maybe because it was just never adjusted properly. You'll find that with a lot of newer Gibsons.

 

Hey - It was a JOKE!

[Johnny Two Tone]

 

 

 

Well, I'm going for a straight neck and then I'll give relief as necessary but it doesn't look too bad right now. I just wanted to ask before I started doing more turning as I've had to turn this rod more than my other guitars rod's ever needed.

 

I just thought it was a strange concept that you could need to turn a rod all the way around or more. I must be missing something on exactly how truss rods work to straighten the neck.

[Mind Riot]

Standard single action truss rods work by counteracting the string pull on a neck. A mild steel rod is inserted into a curved channel in the neck when the neck is made, and it is anchored at one end and has the adjusting nut at the other. The nut is simply a threaded adjuster of some kind, and it moves on the threads of the rod like any other threaded bolt or piece of steel.

 

Since the rod is inserted into a curved channel (with the deepest part of the curve away from the fretboard), the rod will try to straighten itself out thus counteracting the pull of the strings. The strings will pull the neck up away from the player, and the rod pulls it back straight. Getting the relief just right is a balancing act between the string tension and rod adjustment.

 

The neck wood, neck size, scale length, and construction methods will all play a part in it as well. Thinner necks will usually need a little more rod tension to counteract the string pull as there simply isn't as much wood there to give it structural stability. Mahogany necks will often need a bit more rod tension than maple due to maple being a harder, stronger wood. Longer scales will sometimes need a bit more, as the string tension will be greater on them, all else being equal, and the rod will be working to straighten a longer neck. Necks with carbon fiber or graphite reenforcement will often need much less because those materials add so much stiffness.

 

Truss rods vary a lot from guitar to guitar. One guitar may do nothing with a quarter turn, whereas another will achieve or lose a lot of relief from the same adjustment. Of course, we're only talking about single action truss rods.

 

If your rod is turning smoothly, without undue effort, and you're seeing changes in the neck relief then you should be fine. If you're cranking away and nothings happening, or if it's so stiff you can't turn it without a lot of effort, you might be in trouble. And if you're cranking it and you hear a snap and then it spins freely, then you busted the rod. Sometimes it's a good idea to remove the strings and back the adjustment nut all the way off and make sure the threads on both the rod and the nut are clean, and lube things up before you reinstall.

[MahaloVision]

It's common to find truss rods that have been adjusted all the way so that the nut can't be twisted anymore. Some people reach that state where they can't turn it anymore and assume that the rod is busted, when in fact all you have to do is put a spacer in between the nut and the block/neck wood.

[Johnny Two Tone]

Okay, now I know the truss rod is fine. After turning the rod only a little each day it has finally gotten to the point where there is some genuine resistance and the neck is straightening a lot better than before.

 

In other words the rod just must have been loose as a mofo when I got it.

[Attila]

 

- It just spun around loosely when you turned it. There was no tension on it at all.

 

+1

[basschick22]

i don't adjust my truss rods more than a quarter of a turn in a 24 hour period

 

my two cents

[stype]

One thing I read to do if you are working with a trussrod of unknown state is to loosen it before tightening it. You should be able to loosen it to the point where it turns freely and then tighten it back to where it is just starts to resist and then work from there. Over-tightening can cause obvious damage, so its a risky way to determine if the truss rod works.