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  #31  
Old 05-07-2019, 01:26 PM
redir redir is offline
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I thought I had addressed the question too but perhaps I did a poor job of explaining so I will try again...

When I install an adjustable truss rod, I like to use the Martin two way rods now, I just sit the rod in the channel. It doesn't get glued in. I do that jsut in case some day it breaks then all you have to do is remove the neck, easy to do on a bolt on neck, pull the truss rod out and slip a new one it.

If you do the same thing with a CF bar then I think that allows for some slippage before the CF bar 'sets' in place and it jsut might be enough to make the relief off a bit. I have no idea if the guy who built your guitar did it that way. If I do use CF bars I epoxy them in which as far as I know is a common practice. Just offering up a hypothesis, aside from the neutral axis one, you should Google that too
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  #32  
Old 05-07-2019, 01:42 PM
charles Tauber charles Tauber is offline
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I thought I had addressed the question too but perhaps I did a poor job of explaining so I will try again...
Those are good additions to the discussion, but don't answer the OP's question of what options he has to fix the one he already has.
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  #33  
Old 05-07-2019, 02:44 PM
murrmac123 murrmac123 is offline
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Originally Posted by justonwo View Post
Yeah, I don’t mind the digressions. It’s just that very few people actually addressed the questions. Just Charles and Bruce.

Yes, the preference is for the very low weight that comes along with the carbon reinforcement. Once a carbon reinforced neck is stable, it doesn’t need adjustment. Occasionally, you get a headache as in this situation, but for the most part they’re trouble-free. I just really like low weight guitars, and I trust guys like John Slobod, Laurent Brondel, and Howard Klepper to do it right (or make it right if something happens, as in this case).

You can’t even breath the phrase “non adjustable truss rod” without the attending debate about whether it’s an ok thing to do.
You are absolutely right, but not all builders/techs are on the same rarefied level.

These guys you mention know how to make a non-adjustable reinforcing rod work ... but it is knowledge which is not possessed by the vast majority of builders, let alone everyday techs.

btw I would add TJ Thompson and John Arnold to that list...
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  #34  
Old 05-07-2019, 03:34 PM
JonWint JonWint is offline
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Originally Posted by redir View Post
When I install an adjustable truss rod, I like to use the Martin two way rods now, I just sit the rod in the channel. It doesn't get glued in. I do that just in case some day it breaks then all you have to do is remove the neck, easy to do on a bolt on neck, pull the truss rod out and slip a new one it.
Martin kit installation instructions recommend full glue encasement of the double-adjustable rod.

Any play of the rod in the channel would delay the adjustment initiation by the rod. Neck curvature results from continuous pressure of the rod along the length of the neck.
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  #35  
Old 05-07-2019, 06:22 PM
mirwa mirwa is offline
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I thought I had addressed the question too but perhaps I did a poor job of explaining so I will try again..
No, you just had a difference of opinion in regards to the use of adjustable truss rods. I did not get a mention either - sad face

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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.
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Last edited by mirwa; 05-07-2019 at 06:29 PM.
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  #36  
Old 05-07-2019, 07:08 PM
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Bruce actually emailed me offline to help. The two questions were: 1) who has seen this much movement in a non-adjustable setup and 2) what have they done to fix it.

The solution as I gather is either to compression fret or to re-surface the fretboard and re-fret. John will have the guitar soon and will figure it out. I was just thing to educate myself in the meantime. Thanks for all the comments.
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  #37  
Old 05-07-2019, 09:26 PM
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Bruce Sexauer Bruce Sexauer is offline
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There seems to be a misunderstanding here about the nature of a carbon beam in a structural situation. It is not absolutely rigid, but rather flexes a very predictable amount under a given stress. And as it flexes it increases its resistance to flexing further. Wood is similar in this way, but a carbon beam is stiffer than any wood I am aware of, and has another very important quality: it remembers its original form better than any wood. It does not take a set, but maintains its original baseline. The point is, once the wood itself has taken whatever set it will, the carbon retains its form for a very long time. Once the geometry of the neck, in our case, has been adjusted to be as close to ideal as possible under tension, it will tend to remain so as long as there are no changes in the equation.

The role of the wood is also important, as it ever was. Dry, stable, clear, grain aligned Honduran mahogany is what is what am. There are other possibilities, but nothing is actually better. This is for similar reasons to the carbon reinforcement: it is predictable and reliable.
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  #38  
Old 05-07-2019, 11:51 PM
mirwa mirwa is offline
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Originally Posted by Bruce Sexauer View Post
a carbon beam is stiffer than any wood I am aware of, and has another very important quality: it remembers its original form better than any wood. It does not take a set, but maintains its original baseline. The point is, once the wood itself has taken whatever set it will, the carbon retains its form for a very long time.
As per an extract of Bruces comments, why I use Carbon fibre to re-inforce necks that otherwise would be thrown away

Have some fretless inlays and some paint to go, but finished this morning, twin carbon fibre rods, stronger than the wood itself

Before the job, truss rod maxed out and stripped with 35 thou of measured relief, twin rods fitted, truss rod loose, 6 thou measured relief

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  #39  
Old 05-08-2019, 12:22 AM
tadol tadol is offline
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I’d suggest that maybe the question should be - What are the options for adjusting relief in a neck without a truss rod - and the obvious answer is - Start by talking to the builder, if possible, since they’d be the most familiar with how the neck was assembled -
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  #40  
Old 05-08-2019, 06:58 AM
MC5C MC5C is offline
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I guess my answers would be - yes, I would expect some early (first 6 months or so) movement in a neck, primarily because I see that in every guitar I build. So I think it's completely normal. Second, I think a reinforced neck can be quite stable over time - I have a 1957 Hofner that had a fingerboard plane and fret job 30 years ago, and it's only now starting to think about wanting a light fret dress over the fingerboard extension (archtop, floating extension). Third, the neck is made of wood. Wood, even with a stiffener, is not a particularly stable material in the greater scheme of things. Expecting a piece of wood 20" long to hold .005" is a pretty big ask, yet somehow it usually works out.

I would personally not assume that it's done moving, and would take small steps. If you want to get from .010" to a more reasonable .005", I would start with a simple fret dress. Take the high frets down a few thou, and get it happily playable, and play it for another 6 months. See what it does. Then decide if that is acceptable. Make another decision then, having not done anything that isn't reversible. Given the compressibility and movement inherent in wood, I'm not a fan of trying to force the wood into a place it really doesn't want to be with oversize frets. It will just move back over probably quite a small period of time.

Just my opinion...
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  #41  
Old 05-08-2019, 07:51 AM
redir redir is offline
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Quote:
Originally Posted by mirwa View Post
No, you just had a difference of opinion in regards to the use of adjustable truss rods. I did not get a mention either - sad face



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  #42  
Old 05-08-2019, 10:01 AM
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Quote:
Originally Posted by MC5C View Post
I guess my answers would be - yes, I would expect some early (first 6 months or so) movement in a neck, primarily because I see that in every guitar I build. So I think it's completely normal. Second, I think a reinforced neck can be quite stable over time - I have a 1957 Hofner that had a fingerboard plane and fret job 30 years ago, and it's only now starting to think about wanting a light fret dress over the fingerboard extension (archtop, floating extension). Third, the neck is made of wood. Wood, even with a stiffener, is not a particularly stable material in the greater scheme of things. Expecting a piece of wood 20" long to hold .005" is a pretty big ask, yet somehow it usually works out.

I would personally not assume that it's done moving, and would take small steps. If you want to get from .010" to a more reasonable .005", I would start with a simple fret dress. Take the high frets down a few thou, and get it happily playable, and play it for another 6 months. See what it does. Then decide if that is acceptable. Make another decision then, having not done anything that isn't reversible. Given the compressibility and movement inherent in wood, I'm not a fan of trying to force the wood into a place it really doesn't want to be with oversize frets. It will just move back over probably quite a small period of time.

Just my opinion...
I think that's probably the plan. John has built about 30 of these guitars with no adjustable rod and has never seen movement after the first couple of weeks. This may just be an unusual case where movement happens over a longer period of time. He'll be able to diagnose soon and come up with a resolution. It could be as simple as waiting for the neck to completely stabilize and then plane the fretboard.
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  #43  
Old 10-04-2019, 01:33 PM
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Just to come back to this thread. John ended up taking the frets down slightly on the first 2 frets. Those were the culprit for the weird relief. The neck has been dead stable since. I have four guitars with non-adjustable rods and they all seem to work fine.
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  #44  
Old 10-06-2019, 07:59 AM
ruby50 ruby50 is offline
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Justonwo

How light are the instruments you prefer? What do they weigh? Is it overall weight you prefer or balance of neck/body? Thanks.

Ed
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  #45  
Old 10-06-2019, 11:50 PM
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justonwo justonwo is offline
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Justonwo

How light are the instruments you prefer? What do they weigh? Is it overall weight you prefer or balance of neck/body? Thanks.

Ed
It’s both balance and overall weight. These instruments are typically in the 3 lb 10 oz to 14 oz range.
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