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  #31  
Old 04-19-2023, 10:49 AM
Ralph124C41 Ralph124C41 is offline
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I know this is an old thread but I wonder if there is a definitive answer ... i.e. to glue or not to glue.

I ask because I finally got around to changing the strings on my Epiphone Masterbilt AJ500MNS. It has had the same strings on it since I bought it used in October 2019. I'm guessing they are 12-54s and I am going to put some Ernie Ball Aluminium Bronze 13-56s on them and use it for an upcoming jam.

Anyway so I went to change the strings and the nut fell out. I could not see any residue from a previous adhesive. So that surprised me but then I wonder should I apply a drop of some adhesive or white glue or something? I have had no problem with it in the past with these "light" gauge strings and I imagine these medium strings would exert even more pressure and keep the nut in place. And if it works OK, why change it ... just don't lose it when I change strings.

What do you folks think?
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  #32  
Old 04-19-2023, 11:50 AM
runamuck runamuck is offline
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Quote:
Originally Posted by Ralph124C41 View Post
I know this is an old thread but I wonder if there is a definitive answer ... i.e. to glue or not to glue....
What do you folks think?
I small drop of glue prevents the nut from sliding side to side.
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  #33  
Old 04-19-2023, 12:08 PM
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Quote:
Originally Posted by runamuck View Post
I small drop of glue prevents the nut from sliding side to side.
I think small is right too... don't want it to fall off, but it should be easy
and safe for some future tech to remove it.

-Mike
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  #34  
Old 04-19-2023, 12:16 PM
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Bob Womack Bob Womack is offline
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Quote:
Originally Posted by runamuck View Post
I small drop of glue prevents the nut from sliding side to side.
Agree. Superglue is perfect because it has no shear strength. A tap on the end of the nut will release it.

Bob
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  #35  
Old 04-19-2023, 02:42 PM
Ralph124C41 Ralph124C41 is offline
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Thanks for the answers. I called my luthier buddy (who has his own private line of acoustics made from exotic woods) who also suggested a small dab of white glue or something like that. I ended up taking the guitar to him and he applied the glue and put on my supplied set of medium-gauge strings and charged me $0.00. He also said the neck didn't need tweaking. I was going to change the end pins but found out they were bone so I kept them.
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  #36  
Old 04-20-2023, 06:53 AM
redir redir is offline
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Quote:
Originally Posted by Ralph124C41 View Post
It has had the same strings on it since I bought it used in October 2019.

What do you folks think?
I think you need to change your strings more often
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  #37  
Old 04-20-2023, 09:02 AM
Alan Carruth Alan Carruth is offline
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wrench68 wrote:
"I don't want to glue in a nut because I want to maximize downforce through the nut to the neck. Gluing to the end of the fingerboard with hard glue diverts some of the downforce. If someone really wants to secure the nut, I use very thin rubber-based PSA."

The downforce on the nut it produced by the string break over angle, the same as on the saddle. So long as there is enough break angle to keep the string in contact with the throughout it's full vibration cycle, all of the signal will be transmitted from the string to the nut/saddle. I was able to confirm this through experiment. As far as I've been able to figure out, ~15 degrees of break angle should be 'enough'.

The 'job' of the nut is to establish a stationary end point for the string, so that it 'knows' how long it is, and will produce the correct pitch. In theory, you want a massive nut firmly bedded on a rigid neck.

It would seem to me that using a flexible glue under the nut would set up the conditions for a resonance, where the nut is bouncing on the spring of the rubbery layer of glue, or moving sideways, deforming the glue line in shear. Either of these would change the effective string length around the resonant pitch. I would suspect that for any practical thickness of glue line the effect would be at a pitch that only mosquitos would hear, but I don't have data on this.

Strong 'air' or 'top' resonances that produce motion at the bridge are known to produce shifts in the pitches of string partials that fall close to those frequencies. It's possible that 'neck' modes could do that as well. However, in general the neck is a lot stiffer than the top on an acoustic guitar, so the effects would be less. This is not the case on solid body electrics, and I would not be surprised if there were pitch effects there: again, I have no data on that.

I'll note that violin nuts are glued to the end of the fingerboard, but not to the surface of the head. A tiny drop of hot glue is the traditional way, although I'm sure CA is used these days too.

When I was learning to make guitars we made the nuts slightly tapered in width, so that they would slide in from the bass side and wedge in place. A light tap on the treble end pops it out, but otherwise it would stay in even with no string tension.
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  #38  
Old 04-20-2023, 10:06 AM
CharlieBman CharlieBman is offline
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A few dabs of Titebond for me to insure the nut stay in exactly the place I want it.
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  #39  
Old 04-20-2023, 12:41 PM
redir redir is offline
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The way I read:

wrench68 wrote:
"I don't want to glue in a nut because I want to maximize downforce through the nut to the neck. Gluing to the end of the fingerboard with hard glue diverts some of the downforce. If someone really wants to secure the nut, I use very thin rubber-based PSA."

Is that he thinks like there is some sort of airspace under the nut because you glued it to the face of the nut and as such the 'floor' of the nut doesn't have as much pressure on it as it would if it was free floating and not stuck to the edge of the fretboard.

I could be wrong but that is why I didn't bother replying to that.
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  #40  
Old 04-28-2023, 08:34 AM
jjbigfly jjbigfly is offline
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Wondering if a ďspotĒ of adhesive will create an air gap? I have no experience with this, other than the saddles I have done. I put a thin coat of adhesive (THIN!) under the length of the saddle. IF, and I mean if, I understand correctly, I want the underside of the saddle to make full contact. At least I donít think I have hurt the tone of the instrument.
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  #41  
Old 04-28-2023, 02:30 PM
phcorrigan phcorrigan is offline
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Quote:
Originally Posted by jjbigfly View Post
Wondering if a ďspotĒ of adhesive will create an air gap? I have no experience with this, other than the saddles I have done. I put a thin coat of adhesive (THIN!) under the length of the saddle. IF, and I mean if, I understand correctly, I want the underside of the saddle to make full contact. At least I donít think I have hurt the tone of the instrument.
A drop of wood glue or CA will not create a gap between the nut and the neck anymore than they would create a gap between two pieces of wood, as long as it's clamped correctly while drying. That small drop is enough to keep the nut in place, but a light tap on one end is enough to remove it if and when necessary.
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  #42  
Old 05-29-2023, 12:25 AM
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Bought/sold/traded over 100 guitars as a decades-long hobby, working on them, upgrading, etc. Beyond the really nice ones, I've stumbled into a few very playable freebies and cheapies that needed nothing more than a decent nut.

I've become pretty efficient at slacking the strings enough to swap in new/used nuts and then tune up again to test the action. (An electric screwdriver with a homemade "tuning machine grabber thing" makes quick work of repeating the process until I achieve the right fit.)

Point is, unless I press sideways and try to move the nut that I'm testing, it stays in place while I'm tuned up. Once I'm sure I have the right one, a couple tiny dots of superglue underneath will help keep the nut in place the next time I re-string. No difference in tone. Less glue = easier to tap/pop the nut off if I decide to change it again later.

-----------

What I DO believe might muffle tone a wee-bit is using soft material (like cardboard) under a nut that I need to shim up higher. So for raising a nut slightly, I use a thin strip or two of metal (aluminum soda/beer can, easily trimmed with scissors).

Life is short. Experiment.
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  #43  
Old 05-29-2023, 10:40 AM
macuaig macuaig is offline
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Iíve thought people were talking about dumping a layer of wood glue across the nut, which would only introduce a barrier the vibrations now have to get through. But a tiny thin drop or two with the greater contact still being bone-to-nut seems like a good idea, if itís a problem at all.

Iíve been changing all strings at once on this classical, and Iíve assumed the nut could be millimeters off center as long as youíve tuned up after. Iím going on the assumption that for me itís not a problem to leave it loose.
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  #44  
Old 05-29-2023, 10:47 AM
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But hereís my question. Why does the nut need to transmit vibration to the neck at all? The neck must add substantially to transmitting energy to the body? Same for an electric?
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  #45  
Old 05-29-2023, 02:03 PM
Alan Carruth Alan Carruth is offline
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The nuts only 'job' is to tell the string where to stop vibrating. Of course sound can be transmitted to the body via the neck: you can check that any time with a tuning fork (remember those?). However, that's not how the thing is designed to work, and the bridge is the place where the energy transfer really happens. You want the nut to hold still so that the vibration stops there, but realistically a thin layer of wood or paper (which is surprisingly dense and hard when it's compressed like that) shouldn't allow enough vibration of the nut to matter. That's not to say that some folks won't swear they hear it, though: people do tend to hear what they expect to hear.
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