Truss rod use: True or false ?

Construction and repair of Classical Guitar and related instruments
MarkInLA
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Truss rod use: True or false ?

Post by MarkInLA » Thu Jan 03, 2019 1:36 am

Hi. I learned very long ago that the truss rod is only for neck relief; that action is set by saddle height only. For some odd reason,in the last, say, 5 months, I've read several times by several players that they set or have set the action via the T rod. Is there a conclusive answer concerning this ?
Also, my C10's saddle is no more than a 16th of an inch above the bridge top. Due to this, I actually must use the T rod to set the action I like.
It's pretty much where I want it, but the relief has only a smidge bow under the low E. And under the high E it's near dead straight.
I'm always wondering if Cordoba should have cocked the heel a bit more so as to be able to have a higher saddle but with the action I do have now. Why? Because I believe the saddle needs more height to get the sound board to respond a bit better; the taller saddle vibrating that much more..
I have normal tension D'adds on her and I admit it sounds fine. But I was always curious about the T rod v saddle questions in regards to action..
Thanks, M

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Michael.N.
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Re: Truss rod use: True or false ?

Post by Michael.N. » Thu Jan 03, 2019 2:54 am

If you can set the action on a nylon strung guitar (in any meaningful way) by adjusting the truss rod the neck must be made of rubber. You need a two way truss rod to have any control. The pull of nylon strings gives very little control. Look at it this way. If the string tension pulled the neck out of whack by 2 mm's then an adjustable one way truss rod will give you 2 mm + of control. The string tension of nylon doesn't give you 2 mm's though, it's more like 0.2 mm and often less. What do you think the effects of the action at the 12 th fret will be? Precious little. That's the so called control that a truss rod gives you. If you are setting your action with the truss rod then there's obviously something severely wrong with the wood quality of the neck/freboard.
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James Lister
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Re: Truss rod use: True or false ?

Post by James Lister » Thu Jan 03, 2019 9:30 am

Yes, there is a conclusive answer. The truss rod is used to set the relief, but it will also affect the action slightly. Action should be set by adjusting the saddle height.

What is your current string height at the saddle? And exactly how much is a "smidge" of relief? Also, what action are you aiming for at the 12th fret? If you can give us a few numbers, it would be easier to advise.

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MarkInLA
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Re: Truss rod use: True or false ?

Post by MarkInLA » Fri Jan 04, 2019 2:55 am

Hi. Thanks for the quick replies.
I just though of this: Cordoba C10 comes with high tension Savarez Corums on it. They recommend retaining this string in order to get the most response from the box. I instead changed to med-normal tension D'adds due to not so muscular fingers. BUT, I'm thinking now, maybe the norms don't have enough tension TO bow the neck or warrant T rod attention in order TO obtain the intended arch, and by default, action..
I think if I remember correctly that way back a few years I stayed with the Savs on it, but had sanded down the original saddle height..
So, perhaps with original set up (re-obtaining the original saddle height and going back to the intended strings will bear the need TO tighten the truss rod to where the action and relief are at proper specs; and that I naively corrupted all this back then...Yes/no ? M
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CarbonElitist
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Re: Truss rod use: True or false ?

Post by CarbonElitist » Fri Jan 04, 2019 4:28 pm

A truss rod does change the action, but it is very minimal.
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acmost9
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Re: Truss rod use: True or false ?

Post by acmost9 » Fri Jan 04, 2019 4:31 pm

You might be overthinking it, put the strings on you like, check the relief, tweak truss rod a hair either way - then sand saddle or new saddle depending which way it goes to get the height where you like it. Of course the nut's another story.

MarkInLA
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Re: Truss rod use: True or false ?

Post by MarkInLA » Fri Jan 04, 2019 9:52 pm

Perhaps I am overthinking it. I do honor everyone's input. Please don't exert any further help. Enough has been said. I'll work it out..
Much thanks, M

MarkInLA
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Re: Truss rod use: True or false ?

Post by MarkInLA » Fri Jan 04, 2019 11:02 pm

THIS JUST IN: I just ordered Savarez Cristal Corum 500CJ HT strings from GSP. This should return the C10 to its initial intended tension/neck relief. As I said, I don't have the strongest fingers is why I moved away form them to D'add med. tension. But, as that was some 3 years ago (+-) and as I have been diligently practicing/learning many concert type pieces, I actually think my fingers have gotten heavier and stronger.. So, with luck maybe the HTs will feel allot better this time. I'll report back once they're on. M.

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Re: Truss rod use: True or false ?

Post by MarkInLA » Sat Jan 12, 2019 11:55 pm

REPORTING BACK: I DID PUT ON THE new Savarez HTs. Yes the guit is quite louder, the way it was when new. The strings almost beg for dynamics, whereas the Med tension D'Adds don't lend as much to expression. The downside for me, with Med hands/fingers is that they are somewhat tougher to run fast lines (the chromatic run in Capricho Arabe ) as they require more strength from the LH to activate, than the lighter strings..
I'll keep them on til they're spent. Then I'll restring with a new set of the D'Adds I have and make a final decision. Or i'll buy Med. Savs. That could be the ticket to ride....

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joachim33
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Re: Truss rod use: True or false ?

Post by joachim33 » Sun Jan 13, 2019 11:04 am

There is also a mixed 500CRJ, high tension bass, medium tension trebles, which might be another compromise worthwhile trying.

If you are looking for a high quality low tension set, did you give Aranjuez Suave A800 a try?

MarkInLA
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Re: Truss rod use: True or false ?

Post by MarkInLA » Sun Jan 13, 2019 11:20 pm

joachim33 wrote:
Sun Jan 13, 2019 11:04 am
There is also a mixed 500CRJ, high tension bass, medium tension trebles, which might be another compromise worthwhile trying.

If you are looking for a high quality low tension set, did you give Aranjuez Suave A800 a try?
I used to buy Aranjuez, Savarez quite allot as a beginner in the 1960s. And they are perfectly fine.. Only reason I'm with Savs now is merely because the HT Corums where on the C10 new and that Cordoba highly suggests to remain with them. I do wonder sometimes if that's merely because of a deal they may have made with Savarez (you supply us / we'll help you sell them) and that nearly any HT string will be just as good (IE to bring out the intended overall sound for this model)..
I will say this: As of last night I am quite sure I'm going to stay with them (later on maybe try another brand HTs if less expensive). They do give the C10 lots of 'balls'. ...M

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Amy Gaudia
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Re: Truss rod use: True or false ?

Post by Amy Gaudia » Mon Jan 14, 2019 1:43 am

Hi,

I have never understood why a guitar needs to have its neck relieved... If the purpose of adjusting the truss rod is not for action, then what is it for? Can someone help me understand?
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jim watts
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Re: Truss rod use: True or false ?

Post by jim watts » Mon Jan 14, 2019 2:40 am

Amy Gaudia wrote:
Mon Jan 14, 2019 1:43 am
Hi,

I have never understood why a guitar needs to have its neck relieved... If the purpose of adjusting the truss rod is not for action, then what is it for? Can someone help me understand?
Due to the vibration envelope of the strings, relief allows you to set a lower action.

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James Lister
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Re: Truss rod use: True or false ?

Post by James Lister » Mon Jan 14, 2019 9:25 am

Amy Gaudia wrote:
Mon Jan 14, 2019 1:43 am
Hi,
I have never understood why a guitar needs to have its neck relieved... If the purpose of adjusting the truss rod is not for action, then what is it for? Can someone help me understand?
There's a brief description in the FAQ section here:
viewtopic.php?f=11&t=64845#topic13

James
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