I had a bone nut put on by a respected local luthier. That nut is the slipperiest thing since... since slippers, so slippery it's hard to get graphite on it because the pencil slips. Still the same problem.
I don't think it's the nut. I think it's a balky tension roller, at a bad angle, on the Bigsby (B5):
Even with a Vibramate, my angle from roller to bridge saddles is steep. I'll try string-over-roller and see what I get.
But when I lower the pitch with the Bigsby and release, after I release the strings go flat. If the string is hung up in the nut and won't come back, I would expect it to go sharp when full tension comes back on. But if it's hanging up at the tension roller, I would expect it to stay flat.
The replacement tension roller he's got is out of stock at the moment, but an email elicited a prompt reply that they'll be back in a month or so.
Since the Bigsby hasn't always behaved quite so badly, I wonder if it didn't just happen to get rotated to a spot where it hangs up more. The best hope may be polishing and lubrication (UPDATE: Polished bearing surfaces with jeweler's rouge, hosed down with silicone lube, little or no improvement).
Or a Jazzmaster.
Is it possible to do something to the nut of an electric guitar so that the strings begin to stick when they never stuck before?
I recently took a Gibson SG to an extremely reputable local independent shop for a set up. They did a good job, except the strings have been sticking in the nut since I got it back. I've owned the guitar for 11 years and it never had this problem.
I added a Bigsby to it a few weeks before the setup, and had no trouble. I was using the Bigsby regularly in three or four hour rehearsals and just checking the tuning every couple songs. When I got it back it literally could not be tuned. I carefully cleaned the nut, polished the slots with jeweler's rouge, cleaned the slots again, put in a little graphite, replaced the strings, and now it's basically playable until put anything more than very delicate, gentle pressure on the Bigsby. Then wham, it's flat. The Bigsby is no longer usable.
I've been using the same brand and guage of strings with the guitar since I bought it. After I got it back, I replaced them out of a box of ten sets that I bought a couple of years ago.
When I called, the guy I talked to told me it wasn't happening, and if it was, it wasn't their fault, but I should put some 3-in-1 oil in the slots anyway. If it kept happening, even though it wasn't happening, I could take it in and they'd file the nut slots. I asked how the nut slots were too tight now when they were OK a week earlier, and he didn't have an answer to that one.
I didn't get sarcastic on the phone because you can't do that, and besides, it's a small city and they're the local independent shop. I don't want to be That Guy. I'm not taking it back to that shop because I've been on both ends of interactions with unhappy customers, and I've had painful experience with the kind of people who automatically assume that the customer is delusional. That's not the guy you want sawing on your guitar with a file because that's the first theory that popped into his head.
But am I delusional? They think I'm delusional, and I'd like to think that this is a curable delusion. But I'm not deaf. This guitar has a problem now and it didn't before. I took it home, sat down to play it, and it was untunable.
Could it be the changing temperature and humidity this time of year?
I figure I'll just find a local luthier who does repair work and get a Delrin or bone nut put on. But I'm a little jumpy now about letting strangers touch it.