Fretboard extension role in neck reset

[donnyb]

Hello and thankyou for reading.

In relation to neck resets, and especially with 12 stringers, how much role does the gluing of the FB extension to the body top have in preventing neck creep under 12 string tension after resetting a neck ?

Many say that the dovetail joint does all the work, even saying that the FB extension doesnt even need to be in contact with the body top after a reset, as long as the brace in front of the sound hole is firm.

Does the gluing of the FB extension to the body top, with or without shims after a serious neck angle adjustment "help" things, even a little ?

[charles Tauber]

Originally Posted by donnyb

Many say that the dovetail joint does all the work...

Those that say that misunderstand the cause of neck resets. A neck reset rarely has anything to do with the neck-to-body attachment failing. The usual cause of a neck reset is permanent distortion of the geometry of the wood due to prolonged applied string forces - cold creep.

In standard arrangements, the fretboard extension - the portion over the top - provides some added stiffness to the area and some resistance to shearing. Its primary purpose, however, is to provide frets that can be played, extending the range of the instrument. If one choses to never play in that area, it has limited utility.

If the angle of the neck is changed, as in a neck reset, the angle that the neck extension makes with the top of the guitar will also change. If it is simply glued and clamped back down after a neck reset, it will define a second plane, different from the remainder of the neck, one in which each fret will be successively further from the strings than the last. If one doesn't play in that area, that is irrelevant.

If the fingerboard extension is not re-glued to the top as part of a neck reset, the fingerboard will be cantilevered from the body/neck joint and will not touch the top. It should be re-glued to the top. If playability in that area is required, it should be properly shimmed to continue the plane of the rest of the neck.

[redir]

It seems to me that gluing the FB extension is part of the joint over all. I use a bolt on butt joint and consider gluing the extension as part of the neck joint over all. You would also risk getting some weird noises, buzz and so on if you didn't at least tack it down.

[John Arnold]

A typical fretboard is around 1/4" thick, and is too flexible to produce sustaining notes when fretted. For a cantilevered fretboard to be playable, it must be made stiffer, either with an added wood tongue underneath, or by adding stiffeners like carbon fiber. Also, there is a chance that an unglued fingerboard extension could buzz against the top, or raise up (AKA 'ski jump'), causing buzzes or fretting out.
That said, gluing the fretboard is not necessary for resistance to string tension, though it does add to the strength against side impact of the neck.

[donnyb]

Originally Posted by charles Tauber

Those that say that misunderstand the cause of neck resets. A neck reset rarely has anything to do with the neck-to-body attachment failing. The usual cause of a neck reset is permanent distortion of the geometry of the wood due to prolonged applied string forces - cold creep.

In standard arrangements, the fretboard extension - the portion over the top - provides some added stiffness to the area and some resistance to shearing. Its primary purpose, however, is to provide frets that can be played, extending the range of the instrument. If one choses to never play in that area, it has limited utility.

If the angle of the neck is changed, as in a neck reset, the angle that the neck extension makes with the top of the guitar will also change. If it is simply glued and clamped back down after a neck reset, it will define a second plane, different from the remainder of the neck, one in which each fret will be successively further from the strings than the last. If one doesn't play in that area, that is irrelevant.

If the fingerboard extension is not re-glued to the top as part of a neck reset, the fingerboard will be cantilevered from the body/neck joint and will not touch the top. It should be re-glued to the top. If playability in that area is required, it should be properly shimmed to continue the plane of the rest of the neck.

Thankyou Charles. I like your expression "cold creep" and your explanation of it.

[donnyb]

There's some nuances of opinions emerging relating to why to glue it down, but definite on gluing it down regardless.

[redir]

Originally Posted by donnyb

There's some nuances of opinions emerging relating to why to glue it down, but definite on gluing it down regardless.

Welcome to guitar making and repair

The old saying that I grew up on was that, "there is more than one way to skin a cat..." In hindsight that saying sounds kind of cruel but it's true. But in this case, weather you think it's a structural advantage to glue the FB extension down (I do) or don't, there are other reasons that make it a good idea.

All it takes is a dab of glue too. I put a thin line on each side of the truss rod rout. With the neck joint I do you will need to remove that in the future so I use hide glue and not cover the whole thing.

[Taylor Ham]

Cracks alongside the fingerboard extension can also lead to a rapidly changing neck angle as the neck starts folding toward the bridge. while the fingerboard extension may or may not play a role in this, I think it shows the importance of structural integrity of the top in the area

[mirwa]

The fretboard extension glued down gives side support to the neck, if you look at a guitar with an elevated fretboard that is not glued down, the sides are pretty heavy and stiff

Not gluing it down on a guitar that is not designed for it will inevitably lead to soundboard cracks and broken neck sockets

Steve

[donnyb]

All making good sense. Thankyou All.

Ive thought for a while that the stiffness of the body must get weaker over the years, especially with 12 stringers. I wonder what the bodywood fibres look like after 20 years compared with how these looked at original assembly ? Ive read, generally speaking, that once wood fibres get crushed, they're never the same again in terms of strength.

If so, any assistance given to body stiffness must be an advantage . However, is there an effect on sustain or tone at all, seeing its contacting the sound board ?

[donnyb]

Originally Posted by redir

Welcome to guitar making and repair

The old saying that I grew up on was that, "there is more than one way to skin a cat..." In hindsight that saying sounds kind of cruel but it's true. But in this case, weather you think it's a structural advantage to glue the FB extension down (I do) or don't, there are other reasons that make it a good idea.

All it takes is a dab of glue too. I put a thin line on each side of the truss rod rout. With the neck joint I do you will need to remove that in the future so I use hide glue and not cover the whole thing.

One thing (amongst may others) thatIm learning from others in this Forum and by trial and error, especially about guitars ( and my case in point) that have been left sleeping , strung up, in a ceiling void, in a sub tropical climate, for 30 years by the owner (not me), is ...... there's a sign on their bedroom door that says :

"DO NOT DISTURB! ". And in the fine print under " do so at your peril".

There are soooo many variables ,as Ive been warned by others here !