Official Luthiers Forum!

Mario, (and everyone else!), I totally agree that a loose neck joint...or any other part of the guitar...can take away from string vibration. That does not necessisarily mean that a lot of useful string vibration travels through the neck into the guitar body to be turned into acoustic energy, though.   The modes of vibration that would reach the guitar body would have to mostly come through the neck block where they would be compressive forces from the "Z" axis mode of string stretch modulation and then leverage modes where the string was shaking the neck and that was being transferred into the sides and then top.   I don't believe that much at all gets transferred from the fingerboard to the top as my cantilevered fingerboard has shown.   The other example there would be the Humphrey Millenium design with that huge block between the fingerboard extension and the top.

So my beliefs are that loose parts anywhere in a guitar can hurt tone, and that very little useful vibration is transferred from the neck to the body. I think these are two entirely separate issues.   And these issues are also separate from making the neck either stiffer than normal (which many of us do now) or heavier than normal or traditional.   

Unfortunately, proving this would involve some very interesting test fixtures where you could set up a neck and a body and not have the two connected!

I have found it useful to try mentally to separate each and every function and build technique in the guitar that I can and analyze them, then to slowly put them back together so I can think about interactions and which parts of the guitar primarily contribute tone (yes, all, but...) and which primarily contribute to structural integrity.   Another major intellectual breakthrough for me was understanding the differences among stiffness, strength, damping/resonance, and mass. We tend to be traditionally trained, and these qualities in the materials we use are just all jumbled up together.   In the real world of materials science and structural engineering, these qualities are individually important, and they have a lot to do with materials choices and how to best take advantage of the specific qualities in engineering high performance structures...which is what we are making when we build guitars.

Another thing to consider, for whatever it's worth, is that the neck is acoustically connected to the body not only through the neck/body joint but through the strings. In other words, whatever oscillation is happening in the neck is going back into the strings in some form - influencing the strings' oscillation. This influence is heard by the soundboard. The same thing, of course, is happening on the other end - the soundboard's movement being picked up by the strings. It's an endless loop of energy going in all directions, not just a one way street going from the strings into the soundboard on one end and the neck on the other. Nowhere in the loop is the impedance a brick wall. I would be inclined to guess that whatever influence the neck's oscillations (which can't really even be accurately called "the neck's oscillations", because the neck is coupled to the body) has on the sound has more to do with how it affects the strings' behavior than some mental model of energy being passed into the body through the neck joint and then being radiated by the plates and/or the sides.

At any rate, rather than trying to build the upper bout to somehow receive neck vibration energy and turn it into useful sound, it makes more sense to me to not only make the neck joint solid (that goes without saying, I think, and can be acheived in any number of ways, including all the various bolt-on and adjustable designs), but also to make the structure of the neck block support as rigid as possible. And to make the neck itself rigid. A very massive neck would probably be a good thing, too, but that presents other problems. Anyway, this mental model of sort of "containing" the energy, as much as possible, within the strings and the soundboard, makes sense to me (at least until some new piece of information comes along and blows it all apart).

Then again, there are a heck of a lot of fantastic sounding guitars that are not built around these principles at all - guitars that sing with the most heavenly musical voices...

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

I guess the body and hands would have a dampening effect on vibration, or could transfer more of it into the player, which may cause more of an emotional and spiritual connection. Sometimes I pick up a guitar and notice how it seems to send sound through my whole body. The resonance of finding one's voice is a pathway directly to the soul (so they say). That's why churches use singing so much to bring people into a spiritual state.

I also notice that after drilling through concrete all day I feel like a human tuning fork. For some reason that connection came to mind ... hardly subtle.

Oh yes I also a question: I noticed a hole bored into the dovetail face in my kit's neck. Is this common and what is it for? The neck is for an OM I believe (14 fret), and has the diamond headstock (volute?). I thought maybe it is just for milling purposes, but it looked a little big--like the size of a dowel. Should I plug this?

nickton38810.6843402778

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"Preoccupation with an effect gives it power and enhances the error"
from "Your Owner's Manual" by Burt Hotchkiss.

Mario,

Regarding the butt joint: When you say that you can change the neck angle
by shimming, with paper or whatever, what keeps the shims, or a gap, from
showing where the heel meets the body?

Thanks,
Brook

As someone who has done a number of Bolt on Dovetail joints my advice is don't waste your time. If you want to do a dovetail, glue it. If you want to use bolts forget about the dovetail. Others have comented on it's theoretical problems, I used it and can assure you that the problems pointed out with the bolt loosening the joint are true. A bolt on Dovetail is just a harder to do bolt on.

As far as the bolted dovetail joint goes, if I were thinking about using it, I would contact some of the excellent builders who do it, such as Sergei de Jonge, and ask them why they do. Anyone who has decided not to do it has their reasons for not doing it, and those reasons may seem very convincing. Nevertheless, I'm sure a guy like Sergei has some excellent reasons FOR doing it, and those reasons may be equally convincing if you talk to him. He would probably also have well thought-out answers to the concerns expressed by those who argue against the joint. In the end, of course, one has to decide for oneself.

_________________
Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

I think that to assume that anybody has a reason for many of things they do is dangerous.   The reason may just be wrong, or it may be "that's what I was taught", or it may have worked in one particular instance, or they may have just not thought the issue all the way through.   I'm not bagging on any guitar maker in particular, but I think that as guitar makers, we need to truly understand each part of the instrument, each technique we use, each sequence of operations, and we need to question not only others but ourselves on a regular basis.   We also need to know how guitars fail, and that is something you only get to know by doing a lot of repair work.   Guitar makers who have not done their time in the repair trenches are missing a lot of the story.

Brook, I never said I adjusted the neck angle with shims!

We adjust the neck by loosening the bolts, and sneaking0in a piece of sand paper and sanding the heel.

I'll second what Rick said. Many people, some rather famous, may use a method without having given it a complete study. It works, and that's what counts.

But for a method or theory to be truly valid, it needs to stand up to peer review, where it is taken apart and debated. And this is exactly what we've done here. We were able to debate and see the advanatges and disadvantages of this system. There is no way that a straight bolt will allow a dovetail to carry the neck's load; the bolts now carry it. So, why use the dovetail in the first place?

The only reason I see for using it is to please that part of the buying world that still HAS to have a dovetail. These buyers can't see the light anyhow, so as long as they know there's a dovetail in there, even if it isn't doing anything, they're happy.

Take three tail feathers from a dove, and stick 'em where the sun don't shine...in the guitar..."Yeah, there's a dovetail in there..."

I asked Marc Beneteau why he used a bolt on Dovetail (dovetail with a #8 robertson screw) and he said "because that's how I was told to do it." He now uses a but joint.

Mario,

I am probably missing something about what you mean here, but one of
your earlier posts in this thread said:

"And no, no need to remove the bolts to adjust the neck angle. Just
loosen them a turn, and slip some paper in there. The bolts hold the
alignment. In fact, I don't actually use bolts anymore, but studs. I can set
the neck entirely without every slipping a nut on there at all. The studs
hole the neck in place while I work. "

So that is why I asked about the paper.

Brook

OK Mario, I was missing something - I think I get now, you meant slip in a
piece of sandpaper.

Brook

Rick and Mario, your points are well taken, and I tend to agree with you both. I guess I felt the need to interject what I did largely because none of the veteran builders who use this joint have been a part of this discussion, so I don't think we've really had a thorough "debate"... also because of my personal knowledge of Sergei de Jonge: he's got loads of experience, he's done his share of repairs as well, and he's a top-notch craftsman and a really bright guy who does question and examine every aspect of the process, often creating excellent new ways of doing things. I'm not sure exactly what his reasons are for doing the bolted dovetail, and they ultimately might not stand up to your, or my, examination. But his experience and thinking might very well shed some light on the issue that would be of use to someone like Don who is considering trying it.

_________________
Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

Todd, all of us, myself included, do things just because that's the way we've been doing it for however long.   There are any number of techniques, jigs, etc. that I would change in my own shop, but there is such a thing as momentum and it's reciprocal, inertia. But in a discussion like this, I think it's not only fair but required that we all closely examine our beliefs and methods so as to have opinions be as objective as possible.   I think that there is a consensus among luthiers...well maybe not consensus, but certainly majority opinion that there's no statistically significant sonic difference between bolt-on and dovetailed neck joints.   At least that's what I read both here and over at the AG Luthier's Corner. Then there's the shared group experience of many builders large (as in Taylor) and small (yeah, me!) who have found significant advantages to bolt-on necks.   Then there are the careful intellectual analyses of the issues, and I have to say, the argument that once you snug up a bolt, the dovetail cheeks are no longer in good contact makes perfect sense to me.   Not only that, but you could actually wind up with just enough contact to yield some strange rattling and buzzing with a barely touching dovetail.   So whether Serge or whoever does that, it still doesn't hold up to scrutiny as a viable or reasonable neck joint option in my opinion.   Perhaps if Serge read this whole thread, he might even either chime in with something we haven't thought of, OR he might see the error of his evil ways and repent!

LOL..

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"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

[QUOTE=Rick Turner]    Perhaps if Serge read this whole thread, he might even either chime in with something we haven't thought of[/QUOTE]

That was essentially my point. All the arguments that have been made against the bolted dovetail make perfect sense to me as well, but if I were Don, I'd still talk to Sergei or some of the other fine builders who've drawn a different conclusion to find out why. Maybe they DON'T have good, sound, carefully considered reasons that would shed new light on this discussion, but maybe they do. Too bad they're not here.

Just to be clear, it was not my intention to challenge the widespread opinion that bolted joints are just as good, sonically, as dovetails, and that there are many advantages to bolted joints. I am convinced of these things myself and plan to do all my builds for the foreseeable future with adjustable bolt-on necks.

Sergei, btw, has a pretty cool adjustable neck with elevated fretboard design that he uses on some guitars. The guy is no stick in the mud.

_________________
Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/