Movement in Non-Adjustable Neck with Carbon Rod

[justonwo]

I have 5 guitars with non-adjustable necks. Of the five, four of them have never moved (and it's been years for all but the newest). One of my new guitars has a 1/4x3/8" carbon truss rod - the same recipe that I think is used in all my other non-adjustable guitars. Like any new guitar, things are moving around (for example, the action is increasing, as I would expect). The one thing that is very unexpected is that for the first time in my experience (and the builder's), the neck has increased in relief from 0.004 to 0.010" in the span of about 5 weeks.

How many of you out there have seen this kind of movement on a non-adjustable neck? Is the solution to simply wait until things stabilize and then compression fret the relief back where it needs to be? I'm not certain if Jescar offers a thicker 0.025" tang on their EVO 55090 fret wire, so compression fretting may be difficult.

[mirwa]

Why in this day and age would someone build a guitar without an adjustable truss rod, defies logic.

Steve

[justonwo]

Originally Posted by mirwa

Why in this day and age would someone build a guitar without an adjustable truss rod, defies logic.

Steve

There are reasons and that is not helpful.

[BT55]

Originally Posted by justonwo

There are reasons and that is not helpful.

Justin,
mirwa is expressing his opinion and it should not be trivialized. Guitar necks move. The job of a truss rod is to allow adjustments to the neck to keep it within specification. A non adjustable truss rods purpose is only to stiffen the neck. When that guitars neck needs adjustment it serves no purpose at all.

[justonwo]

Guys, you can save the debate about non adjustable rods for another thread. Not only am I keenly aware of all the points of debate and the pros/cons, but so are many builders who, despite some potential downsides, still build with non adjustable rods. They know the salient issues. I also know them. Please refrain from turning this into a thread debating the two systems. I asked specific questions about my guitar. If you can address those questions, that would be appreciated.

[charles Tauber]

I guess I’d start with identifying humidity levels. Has there been a big change recently?

Compression fretting is an option, particularly if you can obtain the tang width you need to do so. Heat pressing the neck is typically a temporary fix and trying to get the right amount of adjustment to a tolerance of .006” is not very realistic.

Frets can be removed and the fretboard levelled to adjust the amount of relief. However, if one I’d going to do that, one might as well replace the Jescar frets with those for which appropriate tang widths are available to deal with future compression fretting.

Those are the options that come to mind.

As an aside, there us the issue of warranty from the builder. Since this is the first that you or the builder has encountered this, is the neck “defective”?

[justonwo]

Originally Posted by charles Tauber

I guess I’d start with identifying humidity levels. Has there been a big change recently?

Compression fretting is an option, particularly if you can obtain the tang width you need to do so. Heat pressing the neck is typically a temporary fix and trying to get the right amount of adjustment to a tolerance of .006” is not very realistic.

Frets can be removed and the fretboard levelled to adjust the amount of relief. However, if one I’d going to do that, one might as well replace the Jescar frets with those for which appropriate tang widths are available to deal with future compression fretting.

Those are the options that come to mind.

Makes sense to me. I think humidity has been pretty much around 50-55% since I got the guitar, though I imagine it was built closer to 40%. Humidity is monitored for each guitar with a Humiditrak.

I think the Jescar 55090 on this guitar comes with two tang widths. I know the nickel 55090 does because my Brondel is compression fretted with 0.020” and 0.025” nickel 55090. But not sure about 55090 EVO.

I have two other guitars from this builder with non adjustable rods. They are three years old and never moved so much as a thou. The builder will know what to do, I’m sure.

[justonwo]

Charles, could you compression fret out the majority of the relief change with a few selective large-tang frets and then Plek out the rest?

[charles Tauber]

Originally Posted by justonwo

Charles, could you compression fret out the majority of the relief change with a few selective large-tang frets and then Plek out the rest?

I don’t know nothin’ ‘bout plekin’. Selective compression fretting should take out the excess relief.

[BT55]

Installing a few frets and pleking the guitar would cost about $400.

The approximate cost of a full refret job is $400.

The approximate cost of installing a dual truss rod is $500.

Any version of a refret is a band-aid solution but the installation of a dual action truss rod is minimally more but provides a permanent fix.

[mirwa]

Originally Posted by justonwo

There are reasons and that is not helpful.

I guess that is a matter of opinion whether it is helpful or not, I teach acoustic guitar building to lay people and I teach aspiring luthiers to become repairers and builders.

It simply makes little sense to me to build an acoustic guitar without an adjustable truss rod, you have a truss rod fitted as per your description, its carbon fibre, just not adjustable, that makes absolutley no sense at all, every argument for not having an adjustable truss rod is null and void with the fitment of the carbon fibre non adjustable unit.

In regards to your specific problem, let me simplify, I will do this with a mathematics example

1=1, if the tension of the strings on the neck equal all factors that give the neck its strength we have a 1 = 1 situation, so the strings are held perfectly the neck maintains the same relief its a 1 = 1 situation.

If we increase the gauge of the strings to a point where the neck can no longer maintain the same relief then we are no longer even and we get excessive relief

Now to your instrument, clearly the thickness of the neck, the grain orientation, the type of wood, the fretboard material the type of frets, the carbon truss rod, all this and more combined cannot keep the strings from creating extra relief, so its an imbalanced situation, 1 does not equal 1 any more.

To repair it, you need to identify where you can add strength back into the neck, and will the added strength be sufficient to return a 1 = 1 situation, be that maybe with compression fretting, be that maybe by dropping your string gauge, be that by replacing the fingerboard with a more dense material, be that changing the neck wood, be that adding another carbon fibre rod, or be that by adding an adjustable truss rod.

A skilled luthier seeing the instrument can advise, a plek machine is a whole different story, the ability of it to be repaired with a plek machine is subjective to the ability of the computer operator actually having some luthierie skills and not console skills

Steve

[charles Tauber]

Originally Posted by justonwo

I have 5 guitars with non-adjustable necks. Of the five, four of them have never moved...

Steve, BT55,

The OP states he has 5 guitars with non-adjustable necks. It appears to be a conscious choice he has made to buy guitars without adjustable truss rods. He has stated that he is aware of the pros and cons of non-adjustable necks and, apparently, has his reasons for wanting guitars with non-adjustable necks, just as some makers have reasons for making them that way. Restating the reasons to have adjustable necks isn't going to change the OP's preference.

The OP's personal experience is now that one in five, 20%, of non-adjustable necks need adjustment that their design doesn't allow. That is, that "stiff", "rigid" non-adjustable necks hold their shape unless they don't - something that most repair people and luthiers already know. The consequence of that is either living with more relief than ideal or the expense of altering the relief in a non-adjustable neck.

If a luthier choses to make a guitar with a non-adjustable neck, unless the owner of that guitar abused the instrument, I'd expect that "repairing" a warped neck that was designed not to warp should be covered by the luthier's warranty: his design and/or material selection was at fault. However, who's going to pay for that work was not the OP's question.

Those considering buying a guitar without an adjustable neck ought to be aware of the pros and cons, as the OP is.

[mirwa]

Originally Posted by justonwo

The one thing that is very unexpected is that for the first time in my experience (and the builder's), the neck has increased in relief from 0.004 to 0.010" in the span of about 5 weeks

If the builder has not seen this happen before, then i would feel its possibly a warrantable repair by them, the question however is, in their design and build constraints, what is the acceptable range of relief they have built the instrument for.

If they built the instrument for a max relief of say 10 thou (not unheard of for a non adjustable neck), then really it does not matter if that relief has come about in 1 day or 1 year, its not a warrantable repair.

Sometimes its irrelevant if its a warrantable repair or not, the builder takes the responsibility of making it the way a customer wants it at their own expense to minimise negative comments on social media platforms. (Not saying thats being done here)

Steve

[Bruce Sexauer]

I charge an extra $200 for carbon reinforcement instead of an adjustable truss rod. This is not because it costs me more in either materials or labor. It is because I expect to need to refret about a third of such guitar’s before delivery. A carbon neck, as I do it, is very stable once it settles under tension. But calculating where it will settle within 5 thou of relief is a bit of a crap shoot. So I set up the guitar, wait a few days, measure reality, and if neccesary I pull all the frets, resurface the fingerboard, and refret the guitar. I have never had to do this a second time.

Personally, I really like the light weight of a guitar w/o a steel truss rod. The down side is that one cannot change string tensions and maintain ideal relief. My smaller guitar’s are built specifically for light strings unless the customer specs otherwise, and my dreads are usually specifically for mediums. Since they will generally actually work better with the correct tension, the carbon reinforcement should not be a problem in either case.

[justonwo]

Thanks, guys.

I guess the temptation was too great. Ha ha! Gotta love the AGF.

I'll talk about the builder because I don't think he's done anything wrong. As Bruce and others say, wood is wood and sometimes it behaves unpredictably. I own three guitars by John Slobod, all of which have carbon reinforcement and no adjustment. Two of those guitars are 3 years old. The relief has not changed even 0.001" since those guitars were built.

I don't know John's exact strategy, but I know he lets the neck settle in a bit before having the final relief profile Plek'ed into the guitar. This has always worked quite well.

My Schoenberg is 5 years old and has no adjustable rod. Again, not even 0.001" of movement.

My Brondel OM-42 (new to me) has been strung up for 2 years with no movement in the neck.

I was hoping this thread wouldn't get into a discussion of the pros/cons of non-adjustable rods vs adjustable. If done properly, a non-adjustable rod can make a fantastic and stable guitar and, yes, as Charles says, I happen to like them.

We have an unusual situation where the relief is now changing since the guitar was strung up. It's not the end of the world and it can be fixed. I expect once it's fixed, it won't need to be touched again for many years. Regardless, John will do whatever necessary to fix it, so this thread is really for my own personal education.

One solution is Plek, of course. The operator in this case, Lewis Santer, is highly skilled. However, as Bruce once advised me, I don't want this issue to be fixed by Plek alone because it'll result in a mis-match of fret heights. Based on my discussion with Charles, Lewis, and others, it sounds like the fix should be relatively simple. Replace a few of the frets and compression fret out most of the relief. Then get the final profile via Plek.