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The shop where I bought my Cabaret really messed up the G nut slot during the set-up they did, making it much too large and maybe also just a bit too deep.
1st time I re-did it I left the action a little high but got a nice clean sound without buzzing. Having the 1st couple of frets audibly sharp got on my nerves, so I lowered it recently, and have been struggling with nut buzz since. I've already redone the slot once which ended up being a bit better but I still need a piece of paper under the string to get rid of all the buzz (I'm sure you'd hear it in a close-mic'ed recording).
I only had a 0.032 file for a string that's more like 0.036" so had to use a 0.036" wound steel string in addition to the file. Evidently that's not very friendly on a CA+soda resin, plus I'm end up with only some of that resin along the walls and just some traces left on the bottom of the slot.
I just received a 0.036" file (MusicNomad, diamond coated with a round business end) so I'm going to make a 3rd attempt.
Questions:
- should deepen the slot first so as I also end up with a resin bottom, or should I rather leave that for a 4th attempt?
- would it be better to build the repair up in two steps in order to be certain that the glue reaches the bottom, or would the 2 parts separate too easily? I do always build the repair up higher than needed and then press down on it with the idea of compacting it.
- give it ample time to dry (say 15 min) or just a few moments/minutes, before cutting off the excess, filing/polishing down and then cutting a new slot?
I'm playing with the idea of asking my dentist if she always finishes her tubes of dental repair resin. I don't like the idea of using the very liquid UV resin used to make "crystal" jewelry but the dental stuff should be perfect.
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04-09-2024 09:47 AM
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I've used UV resin from ebay with success on nut slots. You do need a good UV light source, and even then the cure won't be instant. Give the light some time to work, and it should be fine. I've even used sunlight as the source, and it works after some time. It's hard to give informed advice without actually seeing the slots. If the slot is just too wide, you may be able to just refill it, leaving the CA in it, but mixing CA with UV may not work well. I don't recall every trying that. If you plan to use UV resin over CA, it might be a good idea to completely remove the CA before starting, but I can't say definitively that it's necessary. I just don't know. I've always used one or the other. CA with an activator - sodium bicarbonate, graphite, cotton, or whatever - does work, but it's a lot of work to clean things up and remove excess. UV resin can be wiped off easily before it starts curing, so the mess is far less. I haven't used CA in some time. One thing I've discovered is that whatever you use, having a very smooth surface in the slot is not ideal. It needs some roughness for the adhesive to grab onto.
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Did my post suggest I was planning to mix the 2 methods? I wasn't. I do wonder if there's a benefit to building up a CA filler in layers, or whether there are only drawbacks to such an approach.
Originally Posted by sgosnell
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I would simply fill the slot and redo the whole slot. I use the typical baking soda and ca. The trick is to be patient and let the whole slot fill and really dry well. Then recut the slot. You never need the exact file sizes to get the slots. I have draws full of them, but I also have my favorite files that seem to do the best. A bit of rubbing with a used would string of the same gauge when done. I cannot say how important it is to be patient and methodical in the approach. In the end you save more time and create very little mess. To a large extent these days I do it almost all by feel and looking. I rarely use the fancy measuring tools because the best one is the height of the string over the first fret when fretting the 3rd fret and looking at relief under the 1st fret. A little goes a long way, and a little high is too high. It is almost as if there is not much room for error. The exceptions are those who don't mind high action at the nut and want everything very powerful. That to me is a mistake.
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I always take my time for this, but what's your ballpark time for "really dry well"? Originally Posted by deacon Mark
I always got good results with files of the same or closest higher gauge than the respective string. With nylon strings (like here) you also have the stretch that causes the string to be thinner when at tension.
Sadly Goldtone don't (yet) have a dedicated ZeroGlide for the Cabaret, and having a custom one made will set me back 75$ plus import tax & duties. Not yet certain if I want to spend that kind of money (esp. since their notion of "within 48 hours" appears to be a little too extensible at 5 days since I sent them an inquiry).
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Zeroglide offers an unslotted nut, which one can slot as desired. I wouldn't expect them to provide a preslotted nut for every guitar model in the world.
You did say you have CA still in the slot, and you were possibly planning to use UV resin. If you don't remove all the CA remnants, you would be mixing the two. That might work fine, but again I don't know.
I can only echo Mark's input, and say that cutting a nut slot properly is a time-consuming process, and needs to be done slowly, with many repetitions of filing just a little, replacing the string, trying the fit, and repeating over and over. That's the only way I know of to do it properly. I tend to file quickly at first, to get in the neighborhood of the proper depth, then very, very slowly. One stroke of the file can be too much if done aggressively. Having the proper file thickness makes it a little easier, but a file a little thinner can do the job, by filing with pressure to the sides and making the slot slightly wider than the file. That's a common thing, because I'm not about to buy enough files to have one for every string diameter, and neither is anyone who does this often. The slot should be a thou or two wider than the string anyway, and that's done by feel and experience. It takes practice.
Another option is to just file all the slots deeper, and shim the nut. That's not a terrible fix. The luthier who refretted my 1953 Epiphone shimmed the nut on it, because the new frets were higher than the originals, and thus the slots were too deep with the new ones. Making a new nut is a lot of work, and shimming is quick, easy, and works as well. I had to look hard to see the shim under the nut, and I have no complaints about it.
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There's such a thing as nut width, or thickness, or fretboard radius Originally Posted by sgosnell
I suppose that if my Cabaret had a truly flat fretboard I would probably be able to adapt their standard classical model (if it comes unslotted), but annoyingly I'm dealing with a 30" radius. Too little to be noticeable to the player unless you put a flat 0 fret in...
Gee, that didn't occur to me. Or to clarify I would evidently get rid of the CA remnants if I were to start using resinYou did say you have CA still in the slot, and you were possibly planning to use UV resin. If you don't remove all the CA remnants, you would be mixing the two.
But since you brought up the idea of mixing: would adding some soda or bone dust be a way to make working with the more easily available liquid resins less of a hassle? And obtain a material that matches the surrounding bone better in terms of looks? Did you ever try that?
Yes, shimming a nut is probably less of a potential can of worms than shimming a saddle if not only because the 2 pieces can be glued together once you have the proper height. Did your luthier take down the top or leave the strings completely embedded as if in a 0-fret nut? I've always been told that's not "good" but can't really see why at a functional level.Another option is to just file all the slots deeper, and shim the nut. That's not a terrible fix. ... I had to look hard to see the shim under the nut, and I have no complaints about it.
I'd prefer not to go there for a single problematic slot, though. I did rework at least 2 others but they're about as perfect as can be for now.
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Well, I hesitate between "all's well that ends well" and "boy do I feel stupid" ...
I got out all the necessary bits and pieces, cleared the kitchen table, installed the patient on it and prepared her for surgery (masking almost everything around the nut slot with tape) and decided to use my new file to clean out the existing nut slot.
That looked less awful than I remembered so I put the string back and give things a whirl.
Action: almost too low, which means just about perfect. Fretted at #3 I get a "ping" when tapping just after the 1st fret so the string isn't kissing the fret (let alone "french kiss" to paraphrase what a friend told me about MC brakes
).
There's a bit of an artifact when I pluck really hard, but it's shorter than what I had with my previous repair, and absent or inaudible at more normal playing volumes.
All that really makes me wonder why I filled the slot in the 1st place. It's decidedly V-shaped now but maybe the new file cleared a burr or something I never noticed. I'm holding off final judgment until I replace the string (more than 1 year old by now, though not played all that time). Despite the proper nut action the 2nd fret plays about 5ct sharp when the open string is in tune so the frequent taking it in and out of the slot probably means I now have a borked string.
By now I do have a nice collection of files that should be adequate for all my nylon and steel string needs (maybe I'll add a 50 at some point). All MusicNomads with the weird yellow plastic holders, except the 16.
56, 46, 36, 32, 28, 24, 16 and 13
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Your nuts are important they begin the whole process. If the action at the first fret is not correct, then you cannot do anything else it has to begin at the nut. Included in this process is string spacing which can also contribute to a playable guitar verse's one that is simply off.
A number of years ago I decide I could cut a new nut for my 1949 D'angelico. I wanted to have just a bit more room in the string spacing at the nut. I did the measurements, and the neck width is 1 10/16. I decided I could spread the string spacing at the nut to equal a guitar that had a 1 11/16 width at the nut. I worked carefully and while not the situation you have as such, this came out perfect. The whole guitar was easier to play. It had always been easy and a fast neck but doing this small tweak made it heaven. I remember taking a huge amount of time to get the nut perfect. Just an example of the importance of your nuts.
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Erm, that'd be our fathers' fathers' nuts, no? Originally Posted by deacon Mark
In my (limited) experience the effect of too high action at the nut on intonation does decrease when you go up the neck. And the effect of a badly cut slot (buzzing) disappears as soon as you put a finger down on that string.
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I would not add anything to the UV resin. Working with them is not a hassle for me. It's far less hassle than working with CA. Originally Posted by RJVB
There's such a thing as nut width, or thickness, or fretboard radius I suppose that if my Cabaret had a truly flat fretboard I would probably be able to adapt their standard classical model (if it comes unslotted), but annoyingly I'm dealing with a 30" radius. Too little to be noticeable to the player unless you put a flat 0 fret in...
Gee, that didn't occur to me. Or to clarify I would evidently get rid of the CA remnants if I were to start using resin
But since you brought up the idea of mixing: would adding some soda or bone dust be a way to make working with the more easily available liquid resins less of a hassle? And obtain a material that matches the surrounding bone better in terms of looks? Did you ever try that?
Yes, shimming a nut is probably less of a potential can of worms than shimming a saddle if not only because the 2 pieces can be glued together once you have the proper height. Did your luthier take down the top or leave the strings completely embedded as if in a 0-fret nut? I've always been told that's not "good" but can't really see why at a functional level.
I'd prefer not to go there for a single problematic slot, though. I did rework at least 2 others but they're about as perfect as can be for now.
He did nothing to the top. The slots were cut just about perfectly before the refret, which just made all the frets higher. The shim was just to match the new frets. I had the refret done just because I didn't like the original small frets (if they were even original ). Deep nut slots can work, but ideally they should be half the string diameter for the wound strings, and the string diameter for the plains. For a nylon string instrument, I don't know what the standard is.
Is the neck behind the fretboard flat, or 30" radius? I'm not certain that I understand what you mean. If the fretboard radius is 30", it's easy enough to match the top of the nut to that, it just needs a file. But again, I'm not sure I'm understanding you.
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Same here... if you mean the part of the neck mat(ch)ing the underside of the fretboard I would assume it's flat, but that surface isn't relevant so I have to assume you mean the part that supports the nut. I haven't yet taken the nut out so I'll have to assume it's flat but just how flat and whether or not it's at an angle you wouldn't expect will be a surprise. Originally Posted by sgosnell
Fretboard radius isn't much of an issue for making a normal nut: I suppose you match the fretboard radius by eye, then file the slots and then maybe adjust the top of the nut a bit more. For a custom ZeroGlide the radius should match perfectly because upper of the 2 "ledges" cut on the nut is effectively a tiny extension of the fretboard on which the rear end of the 0fret will rest. (That's the only reason why I evoked the radius, IIRC.)
Maybe 30" is so close to flat that one could take a standard flat classical ZeroGlide, adjust it such that that upper ledge is flush with the edges of the fretboard, and hope that a glued-in 0 fret will be stable (under nylon string tensions) if it is only supported fully at its ends and by the fretboard but "floating" otherwise.
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FWIW, after having played the guitar with its "unredone" slot I wonder if the little buzz I get isn't simply fret buzz of the string hitting the 1st fret.
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The string buzzing on the first fret is precisely the symptom of a nut slot that is too deep, If it's just a slight buzz then UV resin should work well. Put a little in the slot, just enough to know some is there, and cure it. That might be enough. It's not possible to know with any certainty without checking the guitar. You do want to get enough resin into the slot to allow some slight filing, in order to make sure the takeoff point for the string is at the front edge of the nut. I usually overfill, then file to get the correct depth. You should have the relief you want set beforehand, because changing the relief changes the height of the strings over the first fret. I don't know if your guitar has an adjustable truss rod. If it does, just loosening it by a very small adjustment might fix the buzz, if you can live with just a tiny bit more relief. It's all a matter of deciding which compromises you're willing to accept.
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Unless making it shallower (raising the action) causes intonation at the 1st frets to go off too much, IMHO. There's a compromise to be made here. And I can't be certain the buzz is indeed against the 1st fret; for that I'd have to remove the fret, or find a quick trick to raise the action at the saddle. BTW, the top of the string is more or less flush with the top of the fret. Originally Posted by sgosnell
I know the saddle could be higher; I'm currently at a high-average classical action at the 12th fret thanks to the (double-action) trussrod, but relief is maxed out (as in the last quarter turn or so was a bit scary, so it's not something I'd like to back off on without being certain I won't want to go back up).
I'll be replacing the string first to see how a fresh one behaves. Chances are it'll be tighter because it won't have stretched as much as the current one has, but that also means it'll be just a tad thicker.
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Possibly backbow, and needs some relief. Is the neck straight, is there some relief, or is there actually backbow? That needs to be set correctly before dealing with nut slots, as I said before. Having the trussrod as tight as it will go isn't an encouraging sign. But again, I can't say without handling the guitar. All I can do is make suggestions based on my experience.
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But I just said I have a perfectly passable action height at the 12th fret thanks to maxing out the relief. I don't see how you can deduce backbow from that (maxed out negative relief?).
Yes, the fact I cannot seem to increase relief further than it is does concern me a bit, but then again I wouldn't be able to control it at all on the majority of classical guitars.
The slot is V-shaped by about the same amount as some of the other (not redone) slots that don't cause any buzz, but it's asymmetric. One of the V's legs is more or less vertical; the one on the treble side which is also the crucial one holding the string in place. I suppose the buzz I hear when playing loud enough could be the string alternatingly coming off and hitting against that edge, if it's not simply buzzing against the 1st fret.
I have the same strings on my resonator which has a 12mm shorter scale length, and G string action at the nut is at least as low. I'm not getting any buzz on the open G string there unless I try really hard, but my experience suggests that a longer scale length actually makes (the same) strings more susceptible to buzzing despite the fact that the higher tension they're under. Sounds counter-intuitive, but it probably isn't. Vibration amplitudes are going to be larger, and if you keep the same action at the nut and 12th fret the action at the 1st frets will be lower (basic geometry).
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Nut slots should not be V shaped. They should be U shaped, to match the string diameter, with vertical sides, just a tiny bit wider. Having an asymmetrical V slot can indeed cause buzzy noises. And indeed, longer scale length causes more vibration excursion and thus more likely buzzes. However, longer string length means the string is easier to stretch and fret, so higher action is more comfortable for playing. It's all some sort of compromise.
BTW, the Music Nomad fret files can easily be removed from the handle, and that's how I usually use them for tweaking with the nut in place. The handle makes that awkward, but removing the file from the handle makes it far easier.
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I also take the MN files out of the handle. What's left is very tiny so it requires even more concentration to obtain a perfect straight gesture with them, but it works. The handle makes it impossible to get the action low enough, in my experience - and I can't imagine many people do that fine-tuning with the nut not in place.
Re: slot shape: I'm pretty certain I've seen claims that V shapes are better; they're much less specific to string diameter for instance. Pictures I've seen of slots in archtop saddles also always seem to be V-shaped (but I bet they don't remain that way for long).
You're the first to confirm my impression about scale length, thanks for that. My own experience doesn't really align with the idea that higher action is easier to deal with on a longer scale instrument, though. My 630mm archtop was clearly easier to play than the jumbo I had with a 650mm scale and lighter strings but a jacked-up nut and considerable relief to avoid buzzing. (Past tense because I got rid of the jumbo and put heavier strings on the archtop since
)
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The difference in pressure required to bend/stretch different lengths of wires is real, but it's relative. Think of trying to bend a piece of wire 10 mm long, vs one a meter long, otherwise identical. Another factor is total string length, and string length beyond the saddle and nut. A guitar with a trapeze tailpiece and a large headstock will, all other things being equal (and they never are) be somewhat easier to fret than a normal flat-top guitar, because on the flat-top the strings can't slide over the bridge, and the total string length is shorter. The strings on an archtop with a 630mm string length are usually longer than the strings on a 650mm flat-top, considering total string length. Of course, string composition and diameter, action height, and other factors affect perceived fretting effort as well. Roller bridges, tremolos, etc all have at least some effect.
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