Gibson Firebird with strings binding in the nut - at my wit's end..

[Dan]

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. 

[Allan Bacon]

You mean you don't wear your magnifier headgear all the time? I have to be reminded to take mine off...

[Roger Häggström]

I have started to do this to mark the cuts in the nut. I use a straight edge between the mark for the cut and the stringpin hole in the bridge. That way I get an ever so slightly "fan" cut in the nut. Besides, it's faster than using a square!

[Dan]

Hey Mark.. funnily enough, lutherie.net is where I found this forum. I've absorbed everything I can from that site.. excellent resource!

[Mark McLean]

Hey Mark - thanks for the link back to Paul Hostetter's pages.  There is some great stuff there, beautifully presented with wisdom and whimsy.  I haven't been there for a while and it was great to revisit (and thanks to you, Paul H, if you happen to be visiting this corner of the internet).  

[Russell Vance]

Hi Dan,

lotsa advice been given here. Firstly, I’ve worked with vintage firebirds (which don’t 

have a 1/4” nut - so this is a epiphone spec gibson, standard gibson nut is 3/16.).  No voodoo here, and a graph tech slippery black xl nut will fix the probleM IF THE NUT IS THE PROBLEM.   In particular, a factory slotted GT nut set up with the right string clearance will eliminate the nut as the source of the problem. A string tree will not make yr tuning stability noticeably better or worse wth this headstock configuration which is similar to many other guitars which do what they do OK.   So, first thing:   Replace the nut with a pristine GT item that is untouched by human hands. Change yr strings to a new set of Standard (10_46) strings, stretch the strings as per usual for stage use, run the strings up and down with the tuners a few times to get the nut slippery and then bring the guitar up to tune. If you still have a problem get back to us and we’ll take it from there, Rusty.

[Dan]

Lots to catch up on here! Sorry.. work gets in the way sometimes, had a very busy week so far.

Ok.. Roger - that is an ingenious way to cut your nut slots! I love it!

Russell - thanks for the message and it's great to talk to someone with experience of Firebirds. I removed the last bone nut I cut for it and measured it with calipers and it is indeed 3/16.. or 4.7mm. I have a Graph Tech TusqXL blank on the way to me in the post.. I'm fairly confident I can cut some good slots for it - besides that, I use heavy gauge strings (11-54 - I tune a half step down in my band) so I'd need to mess with the pre-slotted GT nut anyway. I've been looking at photographs of Gibson nuts and it seems that the general consensus reached here - that the nut should be sloped off at the back to provide a small surface area for the string - is what Gibson are doing with their nuts from the factory. The other thing I have to take in to consideration is the way the strings leave the back of the nut - with the vintage style banjo tuners in my Firebird, all the strings break off at a slight angle towards the tuners - so I'll account for that. Any other tips you can throw my way would be greatly appreciated.

[Roger Häggström]

The result from the lastest use of the straight edge. It's very easy to stray from the marking when shaping the cut, but done right the string will bend one time and not two.

[Dan]

Well, here is a quick update..

I had to wait a while because I had some other bits and pieces that needed taking care of. I got round to replacing the nut this morning and following the guide on Lutherie.net I slotted the nut. All the plain strings do not bind in the nut, nor does the wound E string.. but the A and the D are being a nuisance. I don't know what I've done wrong with those two slots, I did all of them under magnification and was extremely careful while doing the work. The only thing that I can think is that the A and D string sit a little deeper in the slot compared to the E, probably about 3/4 of the string is in the slot.. but I wouldn't think that would make a huge difference, or maybe it does?