Ever have one of those weird things where you've seen something a number of times and you're not certain if it's a recent occurrence or whether it's been happening for fifty years but you just haven't noticed it?
Ground-away sections on Gibson truss rod nuts
First off, apologies. Some of the photos here are pretty poor. I was working with a cheapo macro lens on an iPhone in poor lighting (as I didn't have time for anything else). I've tweaked the images a bit (or a lot in one case) so I hope you can see what I'm trying to show.
Over the last few months, I've seen a number of Gibson guitars with damage to their truss rod nuts. This damage is a 'ground-away' section. In some cases, it's pretty heavily ground away and a decent-sized chunk of the nut is no longer there.
Gibson don't tend to mask the truss rod cavity terribly well before spraying so you can see that some of the nuts in these images have lacquer on them, even over the ground-away portion.
Interestingly, these nuts sit lower than the headstock facing so, it looks like the damage occurred as the face of the headstock was being prepped to receive the overlaid facing.
In case these photos don't really show what's happening, maybe this diagram will better illustrate it.
Like I say, this may well have been happening since the dark ages and I've just failed to notice. Or it may just be a spate of weird coincidences that I've had these through the workshop. On that last point, though, I've seen this enough times lately to worry me that it's not an incredibly rare occurrence.
Is it a problem?
Well, it's not the worst thing that could be wrong with your guitar. It certainly weakens the adjustment nut and the risk of further damage — while not zero — is probably pretty small.
I do feel it speaks to the way in which some instruments are built and to their quality control, however, Of course, that's a whole other discussion.