Truss rod - a turn too far?

[Collider]

Been trying to get a lower action on my electro acoustic bass. I reckon I've gone about a 3/4 turn on the truss rod and the action has improved but it still looks like it could take a little more adjustment.

Given the amount I've tightened it already, is it time to stop and get a tech to look at the saddle, nut etc?

[Mickey Mao]

The trussrod adjustment is for setting the relief (curvature) of the neck, and the saddle adjustments are for setting the action.

I'd suggest taking the bass to a qualified tech. At a minimum, I'd suggest reading the sticky on bass setup in this forum.

[WilliamSandoval]

You don't adjust the truss rod for lowering the action. Now your intonation is probably a little off.

[darkstorm]

If you have too much relief, truss rod adjusment for straighter neck will improve low action ability. Tuning tweak will be needed even with a half turn of truss rod. Its no biggee.m Intonation adjustment may be needed to with as much truss rod turning as your doing but no biggee. Better to get neck right rather then worry about tuning tweaks etc.

Ive been doing my own setups for more then 30 yrs. So I can do more truss rod tweaking and turning then Id advise most people to do. However if Ive given the truss rod 3/4 turn, Id wait a bit before turning it more for most basses. Id wait a good half hr to see where neck was at. Then if needed give it another up to half turn. I would also gently bend the neck by hand a little bit to help straighten it during that first past half turn adjustment. But no biggee if you didnt do that. But with sig bow is best to loosen all strings and then do truss rod turning.

Be sure you loosen all strings before any further truss rod turning since you seem to need a fair amount more then most for truss rod adjustment.

As long as truss rod turing doesnt become difficult, you havent entered the area where problems can occur in most cases.
One question though: What bass and what gauge and type strings are you useing? Worse bass Ive ever owned for truss rod adjustment difficulty was carvin neck thru body fiver. Could never really get the close to dead flat neck I wanted with med gauge 45-125 strings due to weak neck on the thing. Only solution would have been go to lighter strings. I ask cause some basses necks just arent made well enough for near straight neck with even medium gauge strings and if your using heavy gauge its gonna be even worse.

[john grey]

Variables:
Wood (type / construction)
Tension of strings (& their type / size) in tuned condition
Nut / bridge
Fret design / height

It's very often a good idea to actually have notes when in the process of a setup. A setup IS a process. Did you know if your truss-rod was in a "pre-tightened" condition prior to your work? This can be very significant.
Depending on the humidity (or lack there of) & type of wood used in the neck, adjustment may not occur right away.
Strings vary (sometimes substantially) in the tension of a tuned state. Alteration of string can change many things. Flats often can be used to achieve a lower action.

IMO going further than 3/4 of a turn may be where you want to stop for now. Look to other factors. Determine if the Truss-rod was tightened to begin with Check relief alterations from one day to the next. Collect the variables & think about what you may have overlooked.

[lowendgenerator]

Originally Posted by darkstorm

As long as truss rod turing doesnt become difficult, you havent entered the area where problems can occur in most cases.

This is what I was going to say. Sometimes, you'll come across a neck that has NO tension on the truss rod. I had a P-bass neck like that. I ended up putting over 2 complete revolutions on it before the truss rod started to do anything.

Now, you may need to apply a slight force to the neck while tightening the rod. I suggest bridging the neck (not the whole bass!) across a few tall books, face down, and putting a little body weight on it while making your adjustment. It helps to make the turn easier, and puts less stress on the truss itself.

DISCLAMIER:lowendgenerator is not responsible if you snap your neck in half attempting this. By reading this you release lowendgenerator of all liability, legally and otherwise.

[RustyAxe]

Originally Posted by Mickey Mao

The trussrod adjustment is for setting the relief (curvature) of the neck, and the saddle adjustments are for setting the action.

I'd suggest taking the bass to a qualified tech. At a minimum, I'd suggest reading the sticky on bass setup in this forum.

The Mao(se) is correct. Many necks are screwed up by trying to adjust the action with the truss rod. Get the neck straight (or nearly so) first, then adjust the saddles. Nut slot height also factors in, but isn't such a big deal on a bass, usually.

[SBassman]

Note that many would say you shouldn't do more than 1/4 turn
Per Day.

[JLS]

Nut slot height also factors in, but isn't such a big deal on a bass, usually.

Um, beg to differ....

[john grey]

Originally Posted by lowendgenerator

This is what I was going to say. Sometimes, you'll come across a neck that has NO tension on the truss rod. I had a P-bass neck like that. I ended up putting over 2 complete revolutions on it before the truss rod started to do anything.

+1
I've seen several instances where no tension has been begun on the Truss-rod. This MAY be due to a factory standard in shipping through long distances and differing degrees of humidity, etc. but without some method to track what you are adjusting, a "setup" can create problems that didn't exist previously.
Make your adjustments as close to one at a time as is appropriate. That way you can determine what is doing what.

Personally I write down what I am doing during a setup and it's been very helpful. I also use quality measuring tools, time, and patients. The less you rush & the more you think about what you are attempting to achieve, the better your chances of a high-quality success.

[RustyAxe]

Originally Posted by JLS

Um, beg to differ....

If the relief is right, the saddle height correct, frets are level, then changes at the nut will affect the first one or two positions, and then only slightly. Because I care, I do adjust the nut slots when I set up a new bass. But really, to someone who doesn't know what a truss rod is for doesn't it make sense to tell them to adjust the nut slots, don't ya think?

[202dy]

Originally Posted by Collider

Been trying to get a lower action on my electro acoustic bass. I reckon I've gone about a 3/4 turn on the truss rod and the action has improved but it still looks like it could take a little more adjustment.

Given the amount I've tightened it already, is it time to stop and get a tech to look at the saddle, nut etc?

When you say that it looks like it could take a little more adjustment, are you saying the relief is incorrect? Or are you using the truss rod to control string height?

String height is adjusted by raising and lowering the saddle. On an acoustic-electric that means loosening the strings and trimming or shimming the saddle. Adjusting string height is the second step in performing a set up. As such, it should not be done until the relief is adjusted correctly.

Turning the truss rod nut adjusts the relief. The number of turns is meaningless. The only important information is whether or not the relief is correct.

If there is too much relief, tighten the nut. Keep turning the nut until the relief is correct. Conversely, if the neck is in a back bow, loosen the nut until the relief is correct.

Notice that there is no mention of how many times, or fractions thereof, to turn the nut. Since every piece of wood, it's moisture content, age, density, etc. is different any prescribed number of turns is useless because that number may or may not adjust the relief to the required spot.

What does this mean? It means to turn the nut until the neck is right. The only caveat is to stop when the nut becomes too tight. Anyone who has worked on mechanical items like a car knows the feel of twisting a wrench on a nut that is already snug. The good news is that the nut will tell you when to stop. It will emit a loud squeak.

What about neck settling? Sometimes the neck will move. Sometimes it won't. When it does, it usually settles after an hour or two. If that happens, turn the nut some more.

So what about all the information concerning only turning the nut a quarter revolution, or a half revolution, or what ever fraction, once a day. Simple. It is an old wives' tale. Nothing bad will happen to the truss rod as long as you understand and respect that when the nut is tight to stop.

When the relief is adjusted correctly it is time to shim or trim the saddle to adjust the string height.

[JLS]

Originally Posted by RustyAxe

If the relief is right, the saddle height correct, frets are level, then changes at the nut will affect the first one or two positions, and then only slightly. Because I care, I do adjust the nut slots when I set up a new bass. But really, to someone who doesn't know what a truss rod is for it makes sense to tell them to adjust the nut slots, don't ya think?

Nut slot height will significantly affect action out to about the 7th fret, and "slightly" isn't the term I'd use.

The OP should take this to a pro, I think.

[Collider]

Thanks for all the informative replies guys.

[electracoyote]

Originally Posted by Collider

Thanks for all the informative replies guys.

Do you know how to check the relief of your fingerboard?

Once an acceptable relief has been achieved, you're done turning the truss rod. To further improve action, look elsewhere, namely the saddle height, nut slot depths, and neck to pocket/body relationship (in that order IMHO).

[JLS]

Once an acceptable relief has been achieved, you're done turning the truss rod.

This is one of the best ways to explain this, ever.

[southpaw219]

Hey, all. I had a guitar that needed some relief so I loosened the truss rod, all was fine. Then, like a huge dummy, I went to my bass that needed less relief and loosened its truss rod before going "OOOOPS!"

Then, perhaps like an even bigger dummy, I turned it back the other way. Then, I put it down and walked away to flagellate myself.

I hope my absent-mindedness hasn't resulted in any irreparable harm.

[staindbass]

Originally Posted by electracoyote

Do you know how to check the relief of your fingerboard?

put a straightedge on the frets and check the gap in the middle. i like mine almost flat, i leave the space of a medium guitarpick in the middle. if it aint flat, keep turning it, and checking it. i dont use a straightedge, i use the b string. put your finger ON the first fret. ( not between the frets as you would play, otherwise the string will bow up over the fret if you push it to the fingerboard, then it isnt straight anymore) then take your other finger and put it 'on' the fret that is one fret past where the neck joins the body and hold them down. if you put a lamp on the floor you will be able to see the space in the middle of the neck where the string is not touching the frets to judge how much to turn the truss rod nut. ( my first bass had almost a 1/4 inch bow !)

[Staccato]

Originally Posted by SBassman

Note that many would say you shouldn't do more than 1/4 turn
Per Day.

Hopefully you followed the suggestions of the action afficianados posted on various forums. IMO, most people posting about how-to adjust action shouldn't be posting anything on that topic.

After reading many, many how-to threads with photos, I still think twice before adjusting anything more than a skosh at-a-time...

[WilliamSandoval]

Originally Posted by staindbass

put a straightedge on the frets and check the gap in the middle. i like mine almost flat, i leave the space of a medium guitarpick in the middle. if it aint flat, keep turning it, and checking it. i dont use a straightedge, i use the b string. put your finger ON the first fret. ( not between the frets as you would play, otherwise the string will bow up over the fret if you push it to the fingerboard, then it isnt straight anymore) then take your other finger and put it 'on' the fret that is one fret past where the neck joins the body and hold them down. if you put a lamp on the floor you will be able to see the space in the middle of the neck where the string is not touching the frets to judge how much to turn the truss rod nut. ( my first bass had almost a 1/4 inch bow !)

I just adjust it until the neck is straight. I don't do anything fancy with measurements or anything. If it looks straight, it's good enough for me.