TRUSS RODS...

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TRUSS RODS...

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JBASHORUN

Posts: 1839
Joined: Jan. 23 2005

TRUSS RODS...

Can someone please tell me why Flamenco and classical guitars do NOT have truss rods? The idea with truss rods is that when the neck bows or distorts, as it often does, the neck curve can be adjusted by tightening or loosening a rod built into the inside of the neck via the socket at the headstock. The principle is simple, and works well, and I regularly check and adjust my electric and steel stringed acoustic guitars in this way.

But why are truss rods never used for Flamencos and classicals? Can anyone please enlighten me?

Jb

REPORT THIS POST AS INAPPROPRIATE | Date Mar. 28 2006 14:43:49

Escribano

Posts: 6415
Joined: Jul. 6 2003
From: England, living in Italy

RE: TRUSS RODS... (in reply to JBASHORUN)

quote:

But why are truss rods never used for Flamencos and classicals?

My guess is steel strung guitars are under a much higher tension which is the force that bows the neck.

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REPORT THIS POST AS INAPPROPRIATE | Date Mar. 28 2006 14:46:43

Jon Boyes

Posts: 1377
Joined: Jul. 10 2003

RE: TRUSS RODS... (in reply to JBASHORUN)

Simon's right, they are not really necessary as the tension is nothing like that with steel strings.

By the way, some DO have truss rods, my Takamine does. You find that on a lot of Electro acoustic guitars.

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REPORT THIS POST AS INAPPROPRIATE | Date Mar. 28 2006 15:23:20

TANúñez

Posts: 2559
Joined: Jul. 10 2003
From: TEXAS

RE: TRUSS RODS... (in reply to Jon Boyes)

Kenny Hill's also have them. Or at least they used to. It also adds a little bit of weight.

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REPORT THIS POST AS INAPPROPRIATE | Date Mar. 28 2006 18:50:55

Armando

Posts: 302
Joined: May 27 2005
From: Zürich, Switzerland

RE: TRUSS RODS... (in reply to JBASHORUN)

Hi JBASHORUN

The lower stringtension on classicals and flamencos is one of the reasons.

Adjustable truss rods are made of steel and that adds considerably weight to the neck. This would result in a bad weight balance on a classical or flamenco guitar. I'm sure that steel truss rods would also absorb string vibration which is bad for the tone. Some luthier however reinforce the neck (especially if made of spanish cedar) with stripes of ebony or rosewood in order to prevent bending of the neck on a long term basis. Whether or not this is necessary is a matter of dispute. Many top instruments do not feature neck reinforcements. I believe that spanish cedar is stiff enough to stand the stringtension. Nowadays some luthiers use neck reinforcements made of graphite, because graphite has very positive properties in terms of stiffness to weight ratio. If the neck is to be stiffen then it's very important that the increase of stiffness is in a favorable ratio to weight increase. If not, the reinforcement would be counterproductive.

Armando

REPORT THIS POST AS INAPPROPRIATE | Date Mar. 29 2006 8:14:21

Guest

RE: TRUSS RODS... (in reply to JBASHORUN)

I agree that the cedar is stiff enough to support string tension. The main reason I use reinforced necks is avoid warping, which can be seen in so many older guitars.
Ebony is a very poor wood for that. Heavy and unstable. Rosewood is a bit the same. I´ve done a lot of tests on woods, and found an african hard wood sort called Kotebe here in Spain, which is extremely stable and just slightly heavyer than the cedar. Also, the gluing or lamination itself makes the neck a lot stronger and stable. I would never build without reinforcement, it´s just so sad to see your instrument die because the neck warps.

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REPORT THIS POST AS INAPPROPRIATE | Date Mar. 30 2006 7:25:53

JBASHORUN

Posts: 1839
Joined: Jan. 23 2005

RE: TRUSS RODS... (in reply to JBASHORUN)

thanks everyone. I would ideally like to prevent my guitar neck from warping, but agree that a truss rod might make it heavy and may even affect the sound. perhaps the strip of wood glued into the back is the best option.

Anders, I've never heard of "Kotebe", and suspect that it is not something my college will have in stock. If possible, please can you recommend an international supplier for a Kotebe neck strip?

Thanks,

Jb

REPORT THIS POST AS INAPPROPRIATE | Date Mar. 30 2006 16:26:30

Guest

RE: TRUSS RODS... (in reply to JBASHORUN)

quote:

If possible, please can you recommend an international supplier for a Kotebe neck strip?

Yeah, I´m not even sure it´s called kotebe, and the wood suplier here ,Polanco, is not what I call very modern. Anyway, they call wood weird names, like pine is called Flanders, which sounds Dutch to me, the wood is most probably from Sweeden or Finland. So maybe Kotebe is something from Asia in the end. I just bought some planks a while ago and left it under horrible circumstances, like dirsect sun, humidity, frost, and the thing did not crack, warp or change size... good wood for reinforcement strips.

A very good, stable, strong, a little bit heavier and harder wood and easy to get is Sapelly... You´ve got to make the strips yourself

I do 6 x 12mm

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REPORT THIS POST AS INAPPROPRIATE | Date Mar. 30 2006 17:58:15

johnguitar

Posts: 208
Joined: Jan. 10 2006

RE: TRUSS RODS... (in reply to JBASHORUN)

There are many ways to make a guitar. Anders says "I would never build without reinforcement" and I say I would never build with reinforcement. Not that I think it is a bad idea, just that an excellent piece of cedar is very strong and stable and it allows just the right amount of flex in the neck which gives you that relief in the fretboard. Relief allows you to lower the action for a good flamenco. If you build with reinforcement then you get less flex and the relief has to be built in. Two good ways of getting the same result.

John Ray
Granada

REPORT THIS POST AS INAPPROPRIATE | Date Mar. 31 2006 22:13:43

JBASHORUN

Posts: 1839
Joined: Jan. 23 2005

RE: TRUSS RODS... (in reply to JBASHORUN)

Thanks for sharing your views, John. I have to admit, I had not even considered how I would give the neck relief. Taking into consideration what you have said, it would probably be easier to allow the neck to flex naturally somewhat, as I'm told between 0.25mm and 0.5mm is suitable for relief.

However, my neck is being made from mahogany, not cedar... I'm guessing mahogany might be "stronger", ie. have LESS flex. So I'm wondering whether I might have to "build in" some relief anyway?

Thanks,

james

REPORT THIS POST AS INAPPROPRIATE | Date Mar. 31 2006 22:24:15

JBASHORUN

Posts: 1839
Joined: Jan. 23 2005

RE: TRUSS RODS... (in reply to JBASHORUN)

Although it still seems at risk from warping without ANY support of some kind. Not quite sure what to do...

Jb

REPORT THIS POST AS INAPPROPRIATE | Date Mar. 31 2006 22:29:46

jshelton5040

Posts: 1500
Joined: Jan. 17 2005

RE: TRUSS RODS... (in reply to JBASHORUN)

If I were using mahogany for a neck I would add some kind of reinforcement. An adjustable trussrod works best. Mahogany is not as stable as Spanish cedar and nowhere near as resistant to warping. Good quality mahogany is also much heavier than Spanish cedar which is not desirable in a flamenco guitar.

In my opinion the only advantage of adding hardwood strips in the neck is that when the cedar is sawn and reglued natural stresses are relieved making the neck slightly more stable. Most hardwoods (ebony, rosewood, etc.) are notoriously unstable and do little more than add weight to a good piece of Spanish cedar. To improve stability it would be better to simply saw the cedar lengthwise and glue it back together or better yet laminate many pieces of cedar creating a plywood.

REPORT THIS POST AS INAPPROPRIATE | Date Apr. 2 2006 14:22:09

JBASHORUN

Posts: 1839
Joined: Jan. 23 2005

RE: TRUSS RODS... (in reply to jshelton5040)

thanks Jshelton!
Since my neck is mahogany, it is quite heavy already. Adding a truss rod will make this one heavy guitar neck! At least for a flamenco guitar. Its a shame I didn't use cedar to start with.

REPORT THIS POST AS INAPPROPRIATE | Date Apr. 2 2006 20:46:40

JBASHORUN

Posts: 1839
Joined: Jan. 23 2005

RE: TRUSS RODS... (in reply to Guest)

quote:

A very good, stable, strong, a little bit heavier and harder wood and easy to get is Sapelly... You´ve got to make the strips yourself I do 6 x 12mm

btw Anders, is that 12 width (as visible on the outside of the neck) or 12 depth (as in deep inside the neck)?

Thanks,

Jb

REPORT THIS POST AS INAPPROPRIATE | Date Apr. 3 2006 9:48:28

Armando

Posts: 302
Joined: May 27 2005
From: Zürich, Switzerland

RE: TRUSS RODS... (in reply to JBASHORUN)

Anders

I did some investigation about the wood you called Kotebe and i didn't find a wood with exactly that name. It is not uncommon that many different names are used to name one and the same woodspecies. I have found a wood called Kotibé which would be an african wood from Ghana, Nigeria, Kameron or Liberia

check this link:

http://www.netzwerk-parkett.de/kotibe.html

With a weight of 76gr/cm3 it would be slightly lighter than indian rosewood.

I think that Hickory could be also a very good choice for a neck reinforcement. Hickory is a kind of american, canadian walnut which is light and very stiff. It is commonly used for drumsticks.

jshelton5040

quote:

If I were using mahogany for a neck I would add some kind of reinforcement. An adjustable trussrod works best. Mahogany is not as stable as Spanish cedar and nowhere near as resistant to warping. Good quality mahogany is also much heavier than Spanish cedar which is not desirable in a flamenco guitar.

The common opinion is that mahogany is more stable than cedar and does not need any additional reinforcement. Mahogany is a collective term and there are many dozens of different species with this name allthough some of them are very different in terms of their visual and physical properties. Cuban mahogany for example is very beautiful but very heavy and not esteemed for the use in guitar luthery. Cuban mahogany is also under CITES now. Honduran mahogany "swietenja macrophilla" is the most used mahogany for luthery nowadays. There was another kind named Tabasco mahogany which was used by Luthiers such as Friedrich but it became short of supply same as the cuban.
I have quite some neck blanks of honduran cedar on stock and i have realized that this woodspecies has great variation in weight. The blanks are all of the same size but the lightest has 580 and the heaviest 900grams. This means that the heaviest cedar blank is heavier than most of the honduran mahogany which is consistently around 800grams.
I beliefe that if the wood (neck and fretboard) is well dried, it is not necessary to reinforce it, not the cedar nor the mahogany. I beliefe though that a reinforced neck will transport more stringvibration (especially those of higher frequencies) to the body which may have a positive impact on the treble response of the instrument.

Armando

REPORT THIS POST AS INAPPROPRIATE | Date Apr. 3 2006 14:00:26

JBASHORUN

Posts: 1839
Joined: Jan. 23 2005

RE: TRUSS RODS... (in reply to JBASHORUN)

Yes, I found the Kotibe too. Over here it is also called "Danta" wood. But it seems no-one stocks this wood, and it is quite rare here. If I use a neck strip, I'll have to go with the Sapele.

Armando, if what you say is true, then my mahogany neck should be stable enough without a truss rod, which is good news. But I went to the store room today, and the technician gave me a cedar neck blank, so I might just start the neck again from scratch if you guys think it will make a big difference. Although my teacher tells me the neck material won't really affect the sound much, just the weight...

Thanks,

Jb

REPORT THIS POST AS INAPPROPRIATE | Date Apr. 3 2006 15:18:18

Armando

Posts: 302
Joined: May 27 2005
From: Zürich, Switzerland

RE: TRUSS RODS... (in reply to JBASHORUN)

JBASHORUN

Your teacher might be right that the weight is more critical than the wood, but the wood has also an influence on the tone. Mostly cedar sounds different to mahogany because it's usually lighter. If you would compare two necks of either wood with the same density then, the difference in sound might be slightly and not noticed by a majority of people.

Armando

REPORT THIS POST AS INAPPROPRIATE | Date Apr. 4 2006 6:34:50

Guest

RE: TRUSS RODS... (in reply to JBASHORUN)

quote:

But I went to the store room today, and the technician gave me a cedar neck blank, so I might just start the neck again from scratch if you guys think it will make a big difference

Go for it, I will definately think it´s a good idea.

That weight in a neck does not influence in sound is IMHO far out. Get a new teacher

Some builders use mahogany for neck blanks in classical guitars in order to add weight = sustain. I consider it to be quite wrong to build a flamenco guitar with mahogany.

I make 2, 12mm high reinforcement strips.

As I said before, the kind of wood you use is not so important, its the lamination itself that matters, and that the wood is stable. I bought some different planks, and left them for a year under horrible conditions, like direct sun, a mont in the bathroom etc, and the Kotebe or whatever it´s called, did not move a at all. It´s not very heavy (a bit heavyer than cedar) or dense and some parts are quite light colored, so that it might look lighter than a dark cedar. (see photo)

I personally prefer a stiff neck and to work the relief in the fingerboard before fretting. I find that you never know how much a neck without reinforcement will bow until you have fretted and stringed the thing. But its all personal.

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 4 2006 7:22:22

JBASHORUN

Posts: 1839
Joined: Jan. 23 2005

RE: TRUSS RODS... (in reply to Guest)

Thanks Armando and Anders. I'm afraid I can't change my teacher, as there are not many people who are willing teach luthiery. even in a big city like London.

quote:

I make 2, 12mm high reinforcement strips.

Anders TWO strips? Is two strips better than one single strip? Also, I noticed from the photo that your stips are on the INSIDE of the neck (underneath where the fretboard will go)... I was going to make one single strip on the outside along the centre of the back of the neck. Which way would be better?

Thanks again for sharing all your wisdom and experience!!!

Jb

REPORT THIS POST AS INAPPROPRIATE | Date Apr. 4 2006 11:59:59

JBASHORUN

Posts: 1839
Joined: Jan. 23 2005

RE: TRUSS RODS... (in reply to JBASHORUN)

Actually Anders, now that I look at the photo again, I see you have also made the neck and neck-block from ONE single piece of wood. I think the slots cut in the block are for the ribs to slot into.

Does this method affect the tone too? Because I used a seperate neck blank and seperate neck block, and the neck block is glued to the inside of the ribs at the top, then I cut a sloping dovetail joint into the block and neck, and put the two together...

Thanks,

Jb

REPORT THIS POST AS INAPPROPRIATE | Date Apr. 4 2006 12:09:06

Armando

Posts: 302
Joined: May 27 2005
From: Zürich, Switzerland

RE: TRUSS RODS... (in reply to JBASHORUN)

JBASHORUN

The type of neck reinforcement as shown on the picture above is a so called hidden reinforcement. Of course two paralel reinforcement stripes result in an even stiffer neck (especially helpful against torsion) than if just one stripe is used.

quote:

I was going to make one single strip on the outside along the centre of the back of the neck. Which way would be better?

I have never seen a reinforcement built into the neck in such manner. If the reinforce is got to be visible it should go through the entire neck height, if it should be hidden, then 12mm as mentioned by Anders is apropriate.

I don't understand exactly where you have built a dovetail joint. A spanish neck however does not feature any dovetail joint. Usually the neck block is glued with flat surface directly on the flat neck blank. Anders neck does not appear to be made of one piece but glued in the way i have mentioned above. A laminated neck block will be more stable than a neck block made of one piece. A one piece neck block in turn would look better comparred to a laminated neck block.

REPORT THIS POST AS INAPPROPRIATE | Date Apr. 4 2006 13:57:11

jshelton5040

Posts: 1500
Joined: Jan. 17 2005

RE: TRUSS RODS... (in reply to Armando)

The common opinion is that mahogany is more stable than cedar and does not need any additional reinforcement. Mahogany is a collective term and there are many dozens of different species with this name allthough some of them are very different in terms of their visual and physical properties. Cuban mahogany for example is very beautiful but very heavy and not esteemed for the use in guitar luthery. Cuban mahogany is also under CITES now. Honduran mahogany "swietenja macrophilla" is the most used mahogany for luthery nowadays. There was another kind named Tabasco mahogany which was used by Luthiers such as Friedrich but it became short of supply same as the cuban.
------------------
I don't know about common opinion. Try putting stress on planks and letting them sit for a year in your shop. That's the way I satisfied myself that Spanish cedar is more resistant to warping than Mahogany. I've used many different kinds of Mahogany (Cuban, Honduran, Peruvian, etc.) and found that the weight does vary dramatically but the good stuff is usually heavy, unlike Spanish cedar in which the best wood is light. I didn't intend to suggest that you can't make a good guitar neck out of mahogany, I've done it myself with some very old, very well cured stock but the odds of someone buying a neck plank of mahogany and getting a decent piece of wood are not good. Much safer to use cedar and unless you know it's cured properly it would probably be wise to laminate it to help the stability.

REPORT THIS POST AS INAPPROPRIATE | Date Apr. 4 2006 14:29:53

Guest

RE: TRUSS RODS... (in reply to JBASHORUN)

James

I use two reinforcement strips hidden inside the neck because it works the best against warping and because I find that it looks the best.

There´s nothing wrong with a dovetail joint, it even gives you the oportunity to work with the neck angle after having finished the body. The way I build is the traditional Spanish way.

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 4 2006 17:25:10

JBASHORUN

Posts: 1839
Joined: Jan. 23 2005

RE: TRUSS RODS... (in reply to JBASHORUN)

Aha, I understand. The Spanish method... I checked in the "Making Master Guitars" book, and it describes it. I will try and use this method for my second guitar.

Thanks again Armando and Anders!!!

Btw, I asked my teacher again if the neck wood affects the tone. he said definitely not. In fact he said the theory was "b*llocks". And that the tone comes 99.99% from the soundboard. I guess different people have different views. I shall try and do some research to investigate.

Jb

REPORT THIS POST AS INAPPROPRIATE | Date Apr. 4 2006 17:37:11

Guest

RE: TRUSS RODS... (in reply to JBASHORUN)

quote:

Btw, I asked my teacher again if the neck wood affects the tone. he said definitely not. In fact he said the theory was "b*llocks". And that the tone comes 99.99% from the soundboard. I guess different people have different views. I shall try and do some research to investigate.

I suppose your teacher calls himself a serious builder. He´s then the first of many that I know or have heard of who has said so.
To me it´s like saying that the vibrations that the guitar transmits through the neck does not influence in the overall sound of the guitar.

I wont even call it theory. Build a couple of leightweight blanca pegheads and you´ll see that they react very different from other nylon string guitars.
If the tone came 99,99% from the soundboard, why should we the discuss the use of different tone woods like cypres or rosewood? They would only change the sound with some 0,01%

That´s what I call theory without any roots in real life.

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 5 2006 6:54:21

jshelton5040

Posts: 1500
Joined: Jan. 17 2005

RE: TRUSS RODS... (in reply to Guest)

To avoid sounding like a cynic let me say that I have little doubt that all the woods used in a guitar affect the sound produced to some degree; however it seems to me that it is very difficult to define the precise effect. Even when two guitars are made to be exact duplicates as in matched pairs for classical players they never sound exactly the same. I personally feel that a blindfolded player would have a very difficult time telling the difference between blanca and negra built by the same maker to the same dimensions. What effect does the neck wood have? How can you say when each neck is a different piece of wood? How does one build enough guitars to establish a baseline to make this kind statement? I've built several hundred and I don't have the answers.

REPORT THIS POST AS INAPPROPRIATE | Date Apr. 5 2006 13:43:46

JBASHORUN

Posts: 1839
Joined: Jan. 23 2005

RE: TRUSS RODS... (in reply to Guest)

quote:

If the tone came 99,99% from the soundboard, why should we the discuss the use of different tone woods like cypress or rosewood? They would only change the sound with some 0,01% That´s what I call theory without any roots in real life.

Anders, thats a good point. I told this to my teacher and he told me a story about the famous guitar maker Antonio De Torres, who made the back and sides of a guitar out of paper-mache to proove that the back and sides of a guitar did not affect the tone:

"Torres knew that lightness was essential in the vibrating surface of an instrument. But a large soundboard, though potentially louder, is heavier than a small one. Making it thinner to reduce its weight would make it weak and flexible, with unfortunate effects on the sound. The solution lay in building a soundboard that was 'domed', arched in both directions, over an arrangement of wooden struts.These famous fan-struts would ensure the static strength of the tapa, the soundboard, while letting it respond to the vibrations of the strings.

The system's efficacy was proved by Torres' experimental guitar, built in 1862, with papier-mache sides and back. This is no longer playable, but those who heard it accepted its maker's contention - confirmed by modern physicists - that only the top of a guitar is of real importance in determining the character of its sound."

(You can read the full version of this text at: http://www.guitarsalon.com/index.php?site_url=115 )

I wasn't around in 1862, so I can't claim to have ever heard such a guitar. But you have to admit that its a pretty persuasive arguement. Apparently it was Torres who originally claimed this, not my teachers. although several of my guitar making teachers (I have 3) have told me this story. The teacher who said that the theory was b*llocks, also claims to be very knowledgeable in acoustics, and gives students lectures on bracing/strut patterns and how tone is produced in guitars.

On the other hand the same teacher who gives these lectures also claims that guitar necks should usually be 100% straight (with no relief), which other people tell me is wrong. So I'm not quite sure who to believe...

Thanks again,

Jb

REPORT THIS POST AS INAPPROPRIATE | Date Apr. 5 2006 15:18:04

Miguel de Maria

Posts: 3532
Joined: Oct. 20 2003
From: Phoenix, AZ

RE: TRUSS RODS... (in reply to JBASHORUN)

Hmmm, Anders how much do you charge for a peghead mache?

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 5 2006 15:50:54

Guest

RE: TRUSS RODS... (in reply to JBASHORUN)

James, I know this Torres story very well, and it is a good argument and a good proof to how we all get judged by our own prejudices, but it is just an argument and nothing else.
Who has played that Torres guitar, in which shape is it (very bad) , what was it compared to etc. Sometimes history change to be myth and for some people myth is the same as religion
I can only say that to me it all matters, that the soundboard is by far the most important part, and that in my ears (and most other ears) cypres and rosewood back and sides produce different "colors" to a guitar.

And no paper maché pegheads from me

If you want a good low action on your guitar, I will advice you to give it a bit of relief, but that´s just my experience, and yes I have build without, which meant taking of the frets, making relief and refretting.

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REPORT THIS POST AS INAPPROPRIATE | Date Apr. 5 2006 16:47:59

JBASHORUN

Posts: 1839
Joined: Jan. 23 2005

RE: TRUSS RODS... (in reply to JBASHORUN)

Thanks Anders. I know that you are a professional luthier, and from what I hear, you make excellent guitars. Therefore, I shall take your word for it on this theory. After all, if the Torres theory were true, there would not be much difference between classicals, blancas, negras, etc. But in reality I know that there is quite a big difference in sound.

Thanks again,

Jb

REPORT THIS POST AS INAPPROPRIATE | Date Apr. 5 2006 17:13:17