First of all.. thanks for letting me join this community, I've had a look round over the last day and it seems like a great place with some extremely knowledgeable chaps. I'm happy to be a part of it.
Secondly, I'm in no way a guitar builder.. but a mere player that happened to take an interest in how to set up his own guitars over the years. Keep that in mind!
So.. let's see if we can hammer this one out together...
I have a 2016 Gibson Firebird that has had issues with the nut from the get go.
Bending strings while playing doesn't immediately send the strings sharp/flat.. but tuning stability does suffer over time with string bending and general playing.
The issue is behind the nut, if I press down on any string - but the wound strings in particular - it will send it sharp by 3-4 cents. If I stretch the string out then it restores to perfect pitch again.
Why would I need to press the strings down behind the nut I hear you say? Well, I don't.. but it highlights an issue that needs resolving.
I have tried a number of different nuts, TUSQXL and bone. Each time it results in the same issue. I had a suspicion at one point it may have been the tuners, but I replaced them (not because of the issue, purely for cosmetic reasons) and the issue was still present.
I'm pretty sure it's down to user error when cutting the nut (combined with a silly design for the headstock), but I've never come across this before with any other guitar I have cut a new nut for. I'm at my wit's end with it and would like to brainstorm some ideas.
The headstock angle isn't as steep as a Les Paul, but the length of the strings behind the nut (at least for the wound strings) is more than any other guitar I have seen. When I cut a nut I tend to angle the slots parallel to the headstock or parallel to the way the strings travel so there is a distinct point of contact at the very front. I have tried opening the back of the nut out to avoid catching there, but it doesn't seem to help. But I'm now thinking that I should cut the nut slots parallel with the fret board and then round off the back of the nut (leaving about a 1mm flat contact point at the very front before rounding it off) - what do you guys think?
I should mention that yes, I have tried every kind of lubrication known to mankind - it doesn't help.
Hey Roger, thanks for your time in reading and replying to me. I do have a feeling the design is flawed. It was a car designer that came up with it after all! However I do know that many other Firebird owners do not have this issue.. so my own abilities have a big part to play here.
I did think about a string tree, I can even use a screw for the truss rod cover as it is positioned right between the 6th and 5th strings. I tested the theory out at the time by pressing down with a screwdriver, but it didn't seem to help. I also thought about decreasing the break angle and put the screwdriver under the strings at the same point and that made no difference either. I know a screwdriver isn't the best way to test the theory out.. so for a few quid I may try it out for real and buy a string tree.
By filing the nut slots parallel with the fret board and rounding the back of the nut over what I'm hoping to achieve is a smooth surface for the string to travel over - as opposed to my fairly drastic angular nut slots (sharp point if contact at the front of the nut with a more or less straight slope for the strings to travel towards the tuners).
I would agree that reducing nut width that contacts the string could help, it looks like a full 1/4" wide nut. You could also consider converting to a roller nut or a zero fret, where the nut only controls string spacing.
The roller nut idea is at the back of my mind as a last resort!
It's not far off a full 1/4".. I work in mm being from the UK, but the nut is 5mm and a 1/4" in 6.2mm.
I'm going to order a blank tonight and get to work on it later in the week so I'll let you guys know how it goes.
In the meantime, if anyone has any bright ideas then by all means put them out there!
I see.. wow, that looks like a nice ukulele Paul. Thanks for sharing those images.
So in your opinion, what is it that makes having less surface area for the string to rest on a better option in this scenario? Would you round off the contact area or keep it flat? If keeping it flat is the best option, would you angle it with the headstock? It's hard to tell from that photo, but it seems as though you have the angle somewhere in between the fret board and the headstock.
Dan, it's actually a tenor banjo.
Thick nuts can create problems with tuning and sitar sounding string buzzing issues. Less surface area = less friction and less chance for the sides of the strings to buzz in the slots. I always tip my nut files just slightly up from parallel, off of the finger board, by the width of my finger. I typically keep the file slot flat, no rounding. If, when the slot is done, I don't get a clear bell tone ring from the string (muted, fuzzy or Sitar sounding buzz), I will tip the nut file at a steep angle toward the head stock and remove some of the rear of the slot. The only instrument I round the slots is a violin nut.
You might be right with your hypothesis that the very long string path beyond the nut, to the tuners, is contributing to the problem with this axe. But you can't change that part of the design. When I build guitars I like to use a zero fret. I find it just simplifies the set-up. I think this product from StewMac looks interesting, to convert from a traditional nut to one that incorporates a zero fret. It might be worth a try in this case.
Paul.. I realised as soon as you said it's a tenor banjo what a schoolboy error I had made! I just saw the four strings and thought Ukulele, not paying attention to the string material at all! Ok.. your theory that less surface area = less friction is making more sense to me now and I'm feeling positive about the new nut. Thanks for the tips.
Hi Mark, thanks for your input as well. I hadn't considered a zero fret and it's certainly more appealing and less of an eyesore than a roller nut. The Zero Glide nut looks like a great option. If the new bone nut with less surface area doesn't work out I think I will go that route.
Dan, here is all the info you need to correct your issue.
Good summary! It doesn't mention one thing I've encountered is on a mandolin of mine. The A strings (it's always the A strings!) were binding and "pinging." on close examination, the builder had cut the slots so they faced in the direction of the tuners at the rear, but the slot was a little too narrow at the back of the nut. The strings were binding against the sides of the slots, forming a perfect little S curve between the front and back and hanging up the strings. Once I found this, a few strokes with the file were all it needed. This can be hard to see--I had to use a magnifier to figure it out because the slot was almost OK--but not quite.