R the F
Luthier / Guitar Maker
Posts: 1,135 
My main instrument is: bandsaw
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Post by R the F on Oct 7, 2016 11:54:15 GMT
No, not those of the Kayan people of what used to be called Burma... More this sort of thing as described by francis . Having had problems with my current approach to attaching the neck at the right angle, it occurs to me that using an adjustable approach could solve the problem for both builder and player. I've looked at what Francis suggests - simple and elegant - and at davewhite 's more elaborate approach - on his website - along with a number of other discussions on a number of builders' forums. The key to making it simple seems to be to keep your pivot point as close to the strings as possible; this obviates the need to readjust the length of the strings which can be shortened or lengthened as a side-effect of some methods of adjustment thus affecting intonation. It also seems absolutely key from my point of view that access should be very unfussy; no loosening the strings or finding special tools in my ideal world. The Howe-Orme system is excellent in this respect, though I would imagine the look of it would worry many players and its pivot point is a long way from the strings (see above) . I also notice that Dave White's has a belt and braces bolt which secures everything once you've finished messing about while Francis relies on the thread of his adjuster countering the pull of the strings to stop the guitar from folding in half if I've understood it right: i.e. if you remove the bolt, the neck is gradually pulled up and is then left hanging by the strings. Seems like an excellent arrangement to me and, in the unlikely event that you wanted to adjust the "yaw" of the neck (left to right orientation) you could just remove the neck and put in some shims. As long as your pivot point is as near the strings as possible, you are not going to affect the intonation - length - of the strings more than an infinitesimal amount. I'm thinking of using the same approach but with a slot in the back (very near the heel) to access a capstan screw instead of having an external bolt head. Would it be worth having adjustable pivots just under the fingerboard accessible through slots in the fretboard about 2 frets above the neck/body join?  I know this discussion has been had a million times amongst luthiers but, if anyone can be bothered, I'd be interested to know how players feel about their necks and how luthiers think it can be sorted elegantly - if there is any point at all, of course. |
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davewhite
Luthier / Guitar Maker
Luthier
Aemulor et ambitiosior
Posts: 3,548
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Post by davewhite on Oct 7, 2016 12:04:27 GMT
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R the F
Luthier / Guitar Maker
Posts: 1,135
My main instrument is: bandsaw
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Post by R the F on Oct 7, 2016 12:10:16 GMT
Already done that bit of research, Dave, though I'm not claiming to have followed all the detail. I notice there was a contribution from this side of the planet in amongst it all, too!
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francis
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Posts: 2,483
My main instrument is: Whatever I'm building...
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Post by francis on Oct 7, 2016 13:43:15 GMT
For me it's too easy to over engineer a system to change the neck angle (or height) to increase/decrease string height. Before opting for the system used on my (now scorpiodog 's J185) I considered placing a brass block in the neck's tenon and a fixed plate within the neck block through which a captured bolt would sit. This would give an adjustment point in the body of the guitar adjacent to the heel cap. I discounted this as there would be no way of (without additional bolt(s)) stopping the bottom of the neck heel lifting away from the body under string loading. Here's a schematic of the J-185 neck adjustment:   The upper brass thrust plate is fixed to the neck block and presses under string loading only against the neck tenon's shoulder |
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R the F
Luthier / Guitar Maker
Posts: 1,135
My main instrument is: bandsaw
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Post by R the F on Oct 7, 2016 14:07:18 GMT
Thanks, francis . Very useful to have the diagram. Funnily enough, I went through the same process of thinking through a vertical adjusting bolt only to realise there would be nothing to stop the bottom of the heel from pulling away. Mine was going to be adjusted through a hole in the fretboard. I'm still wondering if I can get the pivot point even nearer to the fretboard at the moment. Here are a couple of rough variations I've come up with so far:  The diagrams are only really for my use so don't expect to understand what all the lines mean just to give you a general idea. p.s. Has anyone ever considered using cams? You'd have to make them stiff enough to stay put but you need very little movement so near the fulcrum to effect quite a major change at the other end and a subtle cam could do it. |
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francis
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My main instrument is: Whatever I'm building...
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Post by francis on Oct 7, 2016 14:43:37 GMT
R the F Mine ( scorpiodog ) was intentionally built with a raised fretboard as I wanted the upper part of the soundboard 'to work' - the soundhole braces form a letter 'A' and go into the neck block - the upper transverse brace is arched to allow them through.
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davewhite
Luthier / Guitar Maker
Luthier
Aemulor et ambitiosior
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Post by davewhite on Oct 7, 2016 15:07:24 GMT
francis - Your system is elegant. My only worry conceptually is what happens when the player pulls the neck backwards against the string tension. With the neck bolt not being "captured" then in theory the neck will move back into the mortice in the neck block. Probably not a major issue - maybe scorpiodog can comment - and maybe you've added a "whammy bar" neck feature  I would like the adjustable neck system to be locked solid after adjustment. Grant Goltz in America has a similarish simple system to yours and uses a bent piece of spring steel made from a bandsaw blade piece that sits at the top of the tenon against the mortice face. I don't use adjustable necks much anymore since I moved away from mortice/tennon neck joints. Simple, stable externally adjustable systems will definitely have an appeal to some players whose styles of play require different playing actions.
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Post by nkforster on Oct 7, 2016 15:40:49 GMT
The Howe-Orme system is excellent in this respect, though I would imagine the look of it would worry many players and its pivot point is a long way from the strings I don't think the pivot point location is what concerns players. What concerns folk is seeing fresh air between the neck and the body. They don't like it as it contradicts their take on how guitars work. There is a widespread belief that the connection between the neck and the body should be as solid as possible for "tonal reasons." This view is very deeply held amongst both players and many builders. But it's a view which if examined comes to very little. Often folk talk about "transference of tone." I recall the first time I heard this expression I was about 16. I thought it was a silly concept then and still do. Thing is you're in a great position by not making guitars for a living - your work is not tied in with conforming to the views of potential buyers. So just make the neck joint you think is best. Coming up with adjustable necks is god fun, they work very well and after making quite a few I can honestly say in a blind test I couldn't tell you which of my guitars have an adjustable neck. And it's hard to beat the Howe Orme design. n |
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R the F
Luthier / Guitar Maker
Posts: 1,135
My main instrument is: bandsaw
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Post by R the F on Oct 7, 2016 16:17:24 GMT
Thanks for clearing up a couple of things for me, davewhite . It had occurred to me that there wasn't anything to stop the neck being pulled back against the string tension and I've seen videos of chaps who like a bit of languid vibrato giving their necks a good pull. I had also read about the spring steel in Goltz's design although I seemed to have missed the reason for it being there only reading that it wasn't absolutely vital. Now it all fits neatly into place. I also understand why you'd want that final bolt-down since I'm sure players would be worried if they took the strings off and could feel a little movement in the neck. It's just that I'd like to combine that level of security with easy access rather than having to loosen strings and disappear into the soundhole for a fiddle and then tighten up again to see if you'd made any difference to anything. I also agree, nkforster , that it's the look of it that would worry players. And it's not just the daylight; it's also the bit of bent brass and a couple of screws that appear to be holding everything together! I wonder if making a feature of the floating neck (as you have in a different way with your archtops) might be the way the go. I'm still a little worried, though, that having the pivot so far away from the strings might make a significant difference to string length and hence intonation for those out there with fault-finding ears. But, as you say: what do I care? I'm young and slightly unbalanced and there's plenty of time to experiment! |
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francis
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My main instrument is: Whatever I'm building...
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Post by francis on Oct 7, 2016 16:33:19 GMT
davewhite - there is no whammy bar but then there is no great gap behind the tenon - so yes if you want to put that much backward force, out-loading the combined string load then the strings will simply hit the fretboard. From memory with that guitar total inward movement was just enough to make the strings hit the fretboard, outward motion would allow >6mm above the 12th fret if you want to play slide. I doubt that the 6mm metric adjuster will be turned much over a half rotation and cover more than the normal height range for light/heavy - finger-pick or strum work. nkforster I guess I've always thought that the neck/body joint should be a solid as possible - though the couple of adjustable necks have made me think otherwise, and I'm now working more with bolt-on neck joints. Not doing this for a living is fun in that I can essentially take things wherever interest takes me...
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R the F
Luthier / Guitar Maker
Posts: 1,135
My main instrument is: bandsaw
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Post by R the F on Oct 7, 2016 16:54:22 GMT
Working on the assumption that everything imaginable has already been imagined (a few times at least), I've decided to browse through this in bed tonight.  It's an exciting life. |
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leoroberts
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Posts: 26,145
My main instrument is: probably needing new strings
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Post by leoroberts on Oct 7, 2016 17:37:40 GMT
Sweet dreams, Rob - shouldn't be too long in coming LOL
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Post by nkforster on Oct 7, 2016 19:08:19 GMT
I'm still a little worried, though, that having the pivot so far away from the strings might make a significant difference to string length and hence intonation for those out there with fault-finding ears. You might want to look at this again. If the top sinks, that usually results in the bridge moving forward, raising the action. So to re establish the correct action the neck has to tilt back raising the soundhole end of the neck, to re establish the correct scale length the nut has to move away from the saddle. With the Howe Orme joint, pivoting at the heel end the two adjusters under the fretboard push the neck back and away. So both tasks are done at the same time. It's actually the best way to do it - the relationship between action and scale is always the same regardless of how much the top sinks. My Rio HO has about 8' of rotation in the top which is a staggering amount. But because of the neck joint, everything is still in the right place. |
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Post by nkforster on Oct 7, 2016 19:15:49 GMT
nkforster I guess I've always thought that the neck/body joint should be a solid as possible - though the couple of adjustable necks have made me think otherwise, and I'm now working more with bolt-on neck joints. Not doing this for a living is fun in that I can essentially take things wherever interest takes me... Well, most people think it matters, but it doesn't. I stopped using the version of the Spanish heel I came up with - the "English heel" years ago. You can't re set the neck of a guitar with a wedged bridal joint. Not without major surgery anyway. n |
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R the F
Luthier / Guitar Maker
Posts: 1,135
My main instrument is: bandsaw
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Post by R the F on Oct 8, 2016 8:12:29 GMT
I'm still a little worried, though, that having the pivot so far away from the strings might make a significant difference to string length and hence intonation for those out there with fault-finding ears. You might want to look at this again. If the top sinks, that usually results in the bridge moving forward, raising the action. So to re establish the correct action the neck has to tilt back raising the soundhole end of the neck, to re establish the correct scale length the nut has to move away from the saddle. With the Howe Orme joint, pivoting at the heel end the two adjusters under the fretboard push the neck back and away. So both tasks are done at the same time. It's actually the best way to do it - the relationship between action and scale is always the same regardless of how much the top sinks. My Rio HO has about 8' of rotation in the top which is a staggering amount. But because of the neck joint, everything is still in the right place. As ever, you've got me interested, Nigel. I shall be looking at it again. Thanks for the pointer. |
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I would like the adjustable neck system to be locked solid after adjustment. Grant Goltz in America has a similarish simple system to yours and uses a bent piece of spring steel made from a bandsaw blade piece that sits at the top of the tenon against the mortice face.
Jo whoever he is.
