How much adjustment should a truss rod have

[shoulderpet]

Hi

I have a bass with a heel access truss rod, plays fine but I notice the truss rod doesn't seem to turn as far as my other basses.

 

Not sure the best way to describe it and adjusting the truss rod to show what I mean would mean removing the neck so I am going to use the below which shows angles, 360° would mean a truss rod that did not stop turning etc, hope this makes sense

 

Using the below and imagining that the two lines shown below in each angle represent the movement of a truss rod I would say most of my basses in terms of available adjustment would correspond to the picture of the 90° angle, the bass with the heel access truss rod I would say in terms of available truss rod adjustment is more like the picture of the 45° angle 

 

Is this normal, should I be concerned?

 

 

 

 

[itu]

A two way has two threads at the opposite ends, and requires very little turning. A 30 degree turn would equal 60 degrees in a one way unit. How did I find this, you already know...

[Andyjr1515]

If you are starting from a situation that the neck is strung up and the trussrod is already there or thereabouts, then it is unlikely that any 'seasonal' adjustment would ever be any more than 45 degrees to change a slightly high relief to a lower relief.

 

When you say that it doesn't turn as far - do you mean that the resistance gets so great you can't turn it any further?  With the G held down at fret 1 and fret 16, how much of a gap do you have at, say, the 7th?

[shoulderpet]

1 hour ago, Andyjr1515 said:

If you are starting from a situation that the neck is strung up and the trussrod is already there or thereabouts, then it is unlikely that any 'seasonal' adjustment would ever be any more than 45 degrees to change a slightly high relief to a lower relief.

 

When you say that it doesn't turn as far - do you mean that the resistance gets so great you can't turn it any further?  With the G held down at fret 1 and fret 16, how much of a gap do you have at, say, the 7th?

Yes, exactly that, my other basses I can turn the truss rod (if needed) probably a full 90 degrees no problem, this bass I can turn it about 45 degrees and then it doesn't turn any further. 

 

I need to get a set of feelers gauges so not sure if the actual measurements but the relief does by eye look a little more than it should be but the weird thing is that the bass plays absolutely fine, action is lowish, no buzz, no fret rattle.

[Baloney Balderdash]

Enough to put the neck relief right.

[Andyjr1515]

6 hours ago, shoulderpet said:

Yes, exactly that, my other basses I can turn the truss rod (if needed) probably a full 90 degrees no problem, this bass I can turn it about 45 degrees and then it doesn't turn any further. 

 

I need to get a set of feelers gauges so not sure if the actual measurements but the relief does by eye look a little more than it should be but the weird thing is that the bass plays absolutely fine, action is lowish, no buzz, no fret rattle.

Well, if the gap isn't massive and the bass plays fine then I wouldn't worry about it. 

 

Don't worry about feeler gauges - they tend to push the strings up and give oversize readings in any case.  Basically, with the 1st and 16th fret positions held down:

 

- if the string at the mid point is hard against the frets, it needs loosening,

- if the relief is up to the thickness of a credit card and it plays OK, then it's fine

- if it's over, say 1.5mm, then you have a choice - if it plays fine you can leave it alone; if the action feels high to play in places even with the saddles at the right heights, then tighten the rod a touch.

 

[Baloney Balderdash]

A credit card thickness relief is way too much, a business card thickness relief at about 8th fret, with first and last fret fretted simultaneously is more like it.

 

Edited February 18 by Baloney Balderdash

[bremen]

I believe Jamerson used a bible in lieu of feeler gauge, credit card or business card... 😂 

 

[Andyjr1515]

On 18/02/2024 at 17:08, Baloney Balderdash said:

A credit card thickness relief is way too much, a business card thickness relief at about 8th fret, with first and last fret fretted simultaneously is more like it.

 

Yes, I agree with that.  And I would venture to go further.  My personal measure when I'm setting up a bass or a guitar is 'when you tap down on the fret, my ideal is "just perceptible" movement'.  

 

But there's a 'but' when it comes to trussrods.  And that's mainly about who is doing the adjusting.  Because many great bass players are not practical, confident, don't have the right tools or, frankly, don't have any interest in the mechanics of their instrument - and there's nothing wrong with that!  

 

So my general advice, for what it's worth, to anyone reading who regards themselves in that category is:

 

- Don't use the truss rod to adjust action height.  Its only job is to keep the neck straight under string tension

 

- If your bass plays nicely without buzzes at an action you are happy with, then 'if it ain't broke, don't fix it'.

 

- If your bass plays nicely without buzzes at an action you are happy with but you are curious, then by all means, have a look at how much relief (bow-and-arrow curve) you have using the methods described above and:

• if the relief (measuring the amount of curve) is no more than the thickness of a credit card, then either leave it alone, or learn how to/find someone who already knows how to reduce the relief somewhere between @Baloney Balderdash's business card and my 'perceptible gap'...the bass may well play better at a lower action height.
• if it is more than the thickness of a credit card, then learn how to/find someone who already knows to reduce the relief.  As @Baloney Balderdash rightly says, less than this amount of relief would be better, but above this level then the bass's playability will certainly be being compromised.
• if there is no relief at all at the centre point and the string is hard against the 8th fret, then it indicates that the neck may have a back bow (a hump in the middle) and, if so, the truss rod will need adjusting.  It needs loosening or the strings will tend to buzz, particularly around the lower and middle fret positions.   Learning how to/finding someone who already knows how to adjust it will make the bass play better and, usually, allow you to lower the saddles and action.

 

 

- But if your bass is buzzing in places, or action is too high, then learn how to/find someone who already knows how to check the relief.  On a bass, in terms of set up everything affects everything and the set up should always starts with setting the neck relief.  Once that is done, you can assess everything else.

 

Hope the above makes sense.

 

By the way, I answered a basschatter's PM query recently about setting the trussrod and how it works/what it does.  In it I used some googled diagrams/pictures to illustrate and clarify what some of the terms we use mean.  If anyone is interested, more than happy to copy and paste that here.   

 

 

 

 

 

Edited February 23 by Andyjr1515

[Baloney Balderdash]

7 minutes ago, Andyjr1515 said:

Yes, I agree with that.  And I would venture to go further.  My personal measure when I'm setting up a bass or a guitar is 'when you tap down on the fret, my ideal is "just perceptible" movement'.  

 

But there's a 'but' when it comes to trussrods.  And that's mainly about who is doing the adjusting.  Because many great bass players are not practical, confident, don't have the right tools or, frankly, don't have any interest in the mechanics of their instrument - and there's nothing wrong with that!  

 

So my general advice, for what it's worth, to anyone reading who regards themselves in that category is:

 

- Don't use the truss rod to adjust action height.  Its only job is to keep the neck. straight under string tension

 

- If your bass plays nicely without buzzes at an action you are happy with, then 'if it ain't broke, don't fix it'.

 

- If your bass plays nicely without buzzes at an action you are happy with but you are curious, then by all means, have a look at how much relief (bow-and-arrow curve) you have using the methods described above and:

• if the relief (measuring the amount of curve) is no more than the thickness of a credit card, then either leave it alone, or learn how to/find someone who already knows or reduce the relief somewhere between @Baloney Balderdash's business card and my 'perceptible gap'...the bass may well play better at a lower action height.
• if it is more than the thickness of a credit card, then learn how to/find someone who already knows to reduce the relief.  As @Baloney Balderdash rightly says, less than this amount of relief would be better, but above this level then the bass's playability will certainly be being compromised.
• if there is no relief at all at the centre point and the string is hard against the 8th fret, then it indicates that the neck may have a back bow (a hump in the middle) and, if so, the truss rod will need adjusting.  It needs loosening or the strings will tend to buzz, particularly around the lower and middle fret positions.   Learning how to/finding someone who already knows how to adjust it will make the bass play better and, usually, allow you to lower the saddles and action.

- If your bass is buzzing in places, or action is too high, then learn how to/find someone who already knows how to check the relief.  On a bass, in terms of set up everything affects everything and the set up should always starts with setting the neck relief.  Once that is done, you can assess everything else.

 

Hope the above makes sense.

 

By the way, I answered a basschatter's PM query recently about setting the trussrod and how it works/what it does.  In it I used some googled diagrams/pictures to illustrate and clarify what some of the terms we use mean.  If anyone is interested, more than happy to copy and paste that here.   

 

 

 

 

 

Agree with all this.

 

And I too utilize minimal relief, very close to dead straight, that is less than even just a business card thickness.

[shoulderpet]

Ok so positive update, after reading up a bit on truss rods I decided to apply a little bit of grease around where the truss rod turns, applied a little grease loosened the truss rod a tiny bit, tightened it a tiny bit and repeated a couple times then tightened and now the truss rod turns though it's full range with no issues, before it felt very, very tight but turns out it just needed a little grease to get it moving

[Kowad]

On 23/02/2024 at 12:55, Andyjr1515 said:

Yes, I agree with that.  And I would venture to go further.  My personal measure when I'm setting up a bass or a guitar is 'when you tap down on the fret, my ideal is "just perceptible" movement'.  

 

But there's a 'but' when it comes to trussrods.  And that's mainly about who is doing the adjusting.  Because many great bass players are not practical, confident, don't have the right tools or, frankly, don't have any interest in the mechanics of their instrument - and there's nothing wrong with that!  

 

So my general advice, for what it's worth, to anyone reading who regards themselves in that category is:

 

- Don't use the truss rod to adjust action height.  Its only job is to keep the neck straight under string tension

 

- If your bass plays nicely without buzzes at an action you are happy with, then 'if it ain't broke, don't fix it'.

 

- If your bass plays nicely without buzzes at an action you are happy with but you are curious, then by all means, have a look at how much relief (bow-and-arrow curve) you have using the methods described above and:

• if the relief (measuring the amount of curve) is no more than the thickness of a credit card, then either leave it alone, or learn how to/find someone who already knows how to reduce the relief somewhere between @Baloney Balderdash's business card and my 'perceptible gap'...the bass may well play better at a lower action height.
• if it is more than the thickness of a credit card, then learn how to/find someone who already knows to reduce the relief.  As @Baloney Balderdash rightly says, less than this amount of relief would be better, but above this level then the bass's playability will certainly be being compromised.
• if there is no relief at all at the centre point and the string is hard against the 8th fret, then it indicates that the neck may have a back bow (a hump in the middle) and, if so, the truss rod will need adjusting.  It needs loosening or the strings will tend to buzz, particularly around the lower and middle fret positions.   Learning how to/finding someone who already knows how to adjust it will make the bass play better and, usually, allow you to lower the saddles and action.

 

 

- But if your bass is buzzing in places, or action is too high, then learn how to/find someone who already knows how to check the relief.  On a bass, in terms of set up everything affects everything and the set up should always starts with setting the neck relief.  Once that is done, you can assess everything else.

 

Hope the above makes sense.

 

By the way, I answered a basschatter's PM query recently about setting the trussrod and how it works/what it does.  In it I used some googled diagrams/pictures to illustrate and clarify what some of the terms we use mean.  If anyone is interested, more than happy to copy and paste that here.   

 

 

 

 

 

Appreciate all of this, similar to some of the truss rod content I’ve been reading up on 😂

 

I have a p bass that I keep on parking. Even when the truss rod is fully tightened (and locks), there’s still more of an 8th fret gap than I’d like. There are indications that the previous owner also struggled with it - both pickguards that came with it are heavily chipped around the truss rod adjustment access point.

 

I’ve thought, several times, that I should get a luthier to do a professional setup. I’ve spent the weekend tinkering with pretty much everything and it is currently playable. But the truss rod limit nags at me. Is it usual to have a bass that may be just about right when the rod is fully tightened? I feel there should be more play in it. Haven’t had anything like this much beef from any other bass!

 

Edited March 4 by Kowad

[bremen]

On 23/02/2024 at 12:55, Andyjr1515 said:

 

 

By the way, I answered a basschatter's PM query recently about setting the trussrod and how it works/what it does.  In it I used some googled diagrams/pictures to illustrate and clarify what some of the terms we use mean.  If anyone is interested, more than happy to copy and paste that here.   

 

 

 

 

 

Thatd be most helpful, thanks! 

[Aidan63]

7 hours ago, Kowad said:

Appreciate all of this, similar to some of the truss rod content I’ve been reading up on 😂

 

I have a p bass that I keep on parking. Even when the truss rod is fully tightened (and locks), there’s still more of an 8th fret gap than I’d like. There are indications that the previous owner also struggled with it - both pickguards that came with it are heavily chipped around the truss rod adjustment access point.

 

I’ve thought, several times, that I should get a luthier to do a professional setup. I’ve spent the weekend tinkering with pretty much everything and it is currently playable. But the truss rod limit nags at me. Is it usual to have a bass that may be just about right when the rod is fully tightened? I feel there should be more play in it. Haven’t had anything like this much beef from any other bass!

 

In this case it is possible the wood is collapsing and so the truss rod nut/washer has little to bear against and has reached the end of the threaded part, so maybe a neck off remove the nut and take a look to see what's going on or take it to a luthier to check it, maybe why po moved it on

[Andyjr1515]

On 04/03/2024 at 07:55, bremen said:

Thatd be most helpful, thanks! 

I'll post it later today 

[Andyjr1515]

Here's the run through I recently did for a Basschat colleague.  The diagrams aren't mine but I couldn't track down from the google stuff who it was I needed to acknowledge -  so all credit to the folks who drew them!

 

What is Neck Relief ?

One of the first things that is done when setting up a bass is checking the neck relief.  It is easy to check, relatively easy to adjust and can be the difference between a beautifully playing instrument and an unplayable one!

 

This is what it's all about:

 

1. Bass necks are flexible and the string tension tries to bend the neck like a bow-and-arrow string does :

 

2.  To play well, the neck needs to be 'almost' straight and so, internally, there is a trussrod fitted that pulls the neck in the opposite direction to counteract the string tension (I will explain 'almost' straight shortly). 

So, depending on the string tension and the opposite pull from the trussrod, it is possible for the neck to end up straight, or bowed upwards, or bowed backwards.  Greatly exaggerated in this picture but like this:

 

3.  The effect on the playability of the guitar or bass of these three conditions is shown below:

 

 

Note the effect of back bow, in condition 'C' above.  Buzzing from the middle of the fretboard.  And back-bow is the most problematic because the strings will buzz at certain places or certain situations.  

 

And so the general rule for set up of the neck is:

"Get it as straight as possible but without the possibility of back bow occurring."

 

But, because weather conditions change, because we might use alternative tunings, because we might fit a set of different tension strings, and we never want back bow, then we change the above general rule a little, to become:

"Get it as straight as possible, and then add a teeny bit of forward bow"  And that teeny bit of forward bow, showing as a gap between the bottom of the string to the top of the fret is referred to as the 'Neck Relief'

 

 

How do you measure the amount of relief of your bass neck?

 

OK - now to measure the amount of bow on your own neck.

 

And it's VERY easy to do.  And ref below, near enough is good enough.

 

We are going to use the string itself as our straight-edge.  All you need to do:

 

- tune the bass up normally

- hold the G string down to the fretboard in two places - just in front of the nut, and just before the neck joins the body (see pic below)

- while doing that, look at how big a gap there is under the string in the middle of those two points (usually around where the 8th fret position is) (marked with yellow arrow in pic below)

 

 

 

From the side view, this is what you are doing (ignore the gubbins under the fretboard in this picture):

 

 

 

 

Because of the length of a bass, this is easier if you have someone else holding down one of the two positions - or if you have a capo, use that at the 1st fret position to hold that end down.

 

At the mid point (yellow arrow), there are three possibilities:

 

1.  The string has a gap, and it is around or less than 0.5mm (approximately the thickness of a business card).  Teeny gaps can be confirmed by tapping the string down to the fretboard.  If it moves and taps, there is a gap.  If it is rock solid, then refer to 3 below.  This is the ideal situation.  See A in diagram above

 

or

 

2.  The string has a gap underneath, but that gap is larger than 0.5mm / business card thickness.  This is less than ideal.  See B in diagram above

 

or

 

3.  There is no gap at the mid point - the string is hard against the fretboard.  This is not good.  See C in diagram above.