Official Luthiers Forum!

I will agree too Slab, but in my original posted question I wanted to know what others think about the possibility of building a guitar that seriously reduces the need for a neck reset or even bridge replacement.
Doesn't seem to me to be an unreasonable concept, I feel it is worth digging in to and experimenting as I go. I have some projects I'd like to show here soon for critique. Just simple variances and changes to conventional techniques that I feel will strengthen the body/neck without impeding the tone. If no one objects that is..

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Nehemiah Covey
www.coveysacoustics.com

Nehemiah,
Untold numbers of builders are using carbon fiber rods to brace their guitars so that the possibility of needing a neck reset would be slim. These rods are extremely light weight so the added mass shouldnt negatively impact the tone or volume of the guitar.

I dont know that this has been done for long enough for it to be a proven technology, but you are not alone in your quest to develop a guitar that doesnt need a neck reset. On a personal level and as part of my battle with this problem, I cross brace the backs of my guitars, which I am hoping will help hold the dome of the back longer without sacrificing any tonal qualities. I also use a modified Spanish heel neck block. Time will tell if any of this works or not.

One luthier I have seen uses curved bracing for his tops, which I find interesting. This is meant to help counter the belly effect of the top of the guitar.

I would love to see what your approach to this problem is as you have been quite innovative in what I have seen of your work so far.

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Reguards,

Ken H

Ken Parker's neck joint angle adjustable under tension and the neck shouldn't ever need a neck reset. The neck itself is basically carbon fiber covered with wood veneer. The carbon fiber is keyed into the post making it a very strong joint. The neck doesn't touch the top.

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Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

I was not familiar with the neck joint on Ken Parker's archtops. I just checked out his web site and found these two images, that absolutely blow my mind...

http://www.kenparkerarchtops.com/Resour ... side1K.jpg

http://www.kenparkerarchtops.com/Grace/ ... le1000.JPG

It looks like that structure couldn't possibly hold up! I'm not saying it won't, I'm just totally intrigued. If it is, in fact, rigid and stable - and I'm thinking more about the body of the guitar than the neck heel/post itself - and holds up over time, that's quite a feat of engineering. There must be a lot more to it than meets the eye. It looks like it would collapse in no time.

Did any of you see his guitars in Montreal or Miami and get a chance to investigate this?

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Todd Rose
Ithaca, NY

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

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

I've see Ken Parker's incredible guitars and met Ken. Ken is one hell of a nice guy too and very willing to discuss Lutherie with you. His designs IMHO blend the "art" of guitar building/design with the "craft" of guitar building/design as well as any I have ever seen.

In addition, along with Rick Turner's way of thinking Ken Parker's guitars are incredibly playable, superbly set-up and with shapes and features that are as if the guitar is holding you, not you are holding the guitar.

Ken was a pioneer in the creative use of carbon fiber and Kevlar as well as stainless frets. I have no doubt that any design that Ken puts forth will hold up until we are all treading water and perhaps then some.

Pretty cool stuff!

Nehemiah my friend I see that you have mentioned a few times now that the thread has gotten off track. I also suspect that your purpose for this thread was to introduce us to some of your thinking and ideas regarding guitars that will not require neck resets.

Why not just tell us and show us what you have? I would be interested to know what your ideas are.

Thanks

Hesh and Ken F., did Ken Parker discuss his adjustable neck joint? I'd be curious to know more.
On another hand anybody tried building with an arch, side to side (across the grain), instead of a sphere? Obviously the FB extension would need to float or be blocked, like an archtop. I imagine, perhaps wrongly, that it would add strength to the soundbox longitudinally.
The soundhole, IMHO, is the big culprit as every box, sooner or later, will sink a bit in this area.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

Laurent,

You mean like the Howe-Orme?

http://www.vintageinstruments.com/museum/howormgtrfulpage.html

Seems it would add strength, though the soundhole would still be a weak spot. IIRC, Rick Turner said these have great tone.

Pat

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formerly known around here as burbank
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http://www.patfosterguitars.com

Laurent, I can't remember exactly how the post and neck are attached. I could be mistaken but I think the post may be titanium. On the back there is an allen nut that chagnes the angle of the neck so the post must pivot somehow in the neck block, which I think is also maple veneered carbon fiber. Unless you run out of adjustment, I don't think their would ever be the need for a reset. There is also a relief adjustment at the body end of the neck, not sure if it's a standard truss rod or not. Ken makes all of his own parts mostly. I had the table next to Ken at Montreal so we talked a lot, but I never saw pictures of the guts. He may have mentioned something about patents, but he sure likes to talk shop.

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Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

Pat, I think the Howe-Orme tops were pressed into that shape and ladder braced, but that's kind of the idea. I'm thinking of a gentler arch across the whole top & back. In other words instead of being part of a sphere, the plates would be part of a tube.

Am I totally mistaken in thinking the top would offer more resistance to string pull that way? And am I mistaken also in thinking that the arch between head and tail weakens the top along the grain?

Ken, I was imagining the Parker system to have the neck pivot on a stationary post, rather than the post moving.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

It seems to me that an arched top like you're describing would resist deformation from the torque on the bridge better when the guitar is first strung up. However, I don't know if it would resist the gradual deformation that happens over time that much better, if any better at all. The downward force in front of the bridge and the upward force behind will be the same, and the wood will still gradually deform. A somewhat analogous situation, it seems to me, is a floating bridge on an archtop guitar as compared to a floating bridge on a flattop. The archtop resists the downward push better than the flattop initially, but archtops can and do collapse over the years, sometimes quite dramatically. Whatever shape the wood is in initially, it's not going to be in that shape after years of string tension have had their way on this essentially plastic material.

This was the point I was making in my first post in this thread. However, I would qualify what I said in that post... My intention was just to shed light on a basic property of wood and the inevitable effect of the force of string tension over the years. I didn't really mean to say that I think it's absolutely impossible to build a guitar that sounds good and will never need any adjustment to the neck angle. It may be that some designs, which really rigidify the back and sides and the position of the neck block, using other materials such as CF as reinforcement, as well as rethink the engineering of the top in some way, may have a sufficiently limiting effect on how much the action will change over the years. In other words, although string tension will unavoidably distort the wood of the top over the years (if it is, indeed, made of wood), it may be that that could be limited to the extent that the action could be sufficiently adjusted at the saddle, without undue changes in the sound quality (I wouldn't want the saddle height drastically reduced on one of my guitars, because of diminished sound quality), given that the geometry of the back/sides/neck block stays put. I certainly wouldn't want to discourage anyone from attempting to develop such designs.

If your top is a composite of materials, i.e. using CF in the bracing or something like that, then it may be possible to really limit the amount the top will distort over time, since, CF doesn't "creep" like wood.

My other concern with a top arched as you describe, Laurent, is that it wouldn't allow the wood to move as freely with changes in moisture content, so it might be somewhat more prone to cracking.

In any case, when all is said and done, I still think it makes good sense to make a neck joint that allows for relatively easy adjustment of the angle, one way or another - in other words, a bolt-on, with or without an adjustment mechanism.

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Todd Rose
Ithaca, NY

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

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

I am not an engineer and my knowledge of wood is mostly limited to building guitars…
That being said I think wood expands and contracts mostly across the grain and very little, if at all, along the grain. I believe arching the top across the grain would still allow the plate to move up and down, rather than crack with sudden humidity changes.
Not arching along the grain would perhaps offer better resistance to the pull of the bridge. I can't see why the plate would not vibrate as freely that way. It may just be trickier to fit x-braces on such a top because of the compound curve, but it could be patiently done as it is done on an archtop.
Again I may be completely wrong and would love to hear the engineering minds here comment on this.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

Sorry guys I just searched and tried to find it but couldn't...... Anyway there were discussion here on the OLF in which Rick addressed these questions in great detail using the Howe-Orme as examples. I think that Rick has several of these guitars too.

What I remember about the discussions was that the Howe-Orme guitars had cylindrical tops, not domed, and they did indeed resist top distortion very well. Again I am going by memory here.

Perhaps James who has been in touch with Rick could ask Rick to drop in and lend a hand.

The Howe Orme guitar is in the back of the AG with John Hiatt on the cover - the top is neither cylindrical or domed - its pressed into shape, kind of a wave down the centre where the bridge sits. Think arch top without the recurve in profile, and the tail area and binding has the same wave curve shape to it ... very neat looking.

I looked at Ken Parkers guitar and neck joint as well in Montreal ... I was blown away - if I heard him right when I asked him about it, the CF that makes the neck shaft turns 90 degrees and goes down inside the brass piece that hides the adjustment mechanism ... somehow .... the guy is a friggin GENIUS.

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Genius is right Tony bro - Ken has been one of my favorite designers ever since I had the privilege of owning an early Italian Plum Fly.

Here is a pic I took of Ken at HGF in 2006:

Tony, that's how I remember it, too. The adjustment mechanism is in the block, not the neck and the neck is all carbon fiber with a maple veneer covering.

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Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

Yes, wood moves mostly across the grain, not along the grain. It also has some elasticity, thank goodness, or all guitar tops and backs would crack the first time the humidity drops. A domed top takes advantage of the elasticity by allowing the shape of the top to go from more domed to less domed as the wood dries out. It's sort of "pre-sprung", in a way, that makes it more compliant with that movement. Though it's only shrinking across the grain, it can flatten a bit along the grain as well to take up the change in dimensions. A cylindrically arched top won't have quite the same freedom of movement. It isn't really pre-sprung in the same way, it's just bent a bit in one direction. As it dries out, the center will dip down, so that, in cross section, it's less arched, but in side view, it will have to go from straight to concave as the center dips. It won't do that as easily as a domed top will go from more domed to less domed.

Whether or not, in actual practice, this will make much of a difference in the crack-resistance of the top, I really can't say. I'm just describing the theory of it, as I understand it. If anyone wants to step in with more detailed knowledge of wood movement, or experience with cylindrically arched tops, and disprove what I'm saying, please do so.

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Todd Rose
Ithaca, NY

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

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