Re: Les Paul won't stay in tune
You don't say which model of LP you have, but I have had this kind of problem on a couple of my Gibsons.
The first thing to check is the bridge. If you have the traditional vintage ABR-1 bridge, check the saddles VERY carefully. Sometimes the intonation screw can flip up out of it's slot, so you'll need to make sure that all of the saddles are seated properly--it should be a tight fit; they have to snap into place. It can be hard to see. Sometimes they only pop up when under tension--if that is the case, the bridge is probably defective and should be replaced under warranty. This will not happen if you have the more modern Nashville bridge. BTW, on the ABR-1, the intonation screw heads should be next to the pickup.
Also, where your strings cross the bridge...you don't want the string to actually touch the body of the bridge; you want to make sure that it is a clean shot from the stop tail to the apex of the saddle.. If your stop tail is all the way down, try raising it a bit. ABR-1 bridges are a bit fragile, and they can collapse. It is often a bad idea to screw the stop tail piece all the way down--it can put too much pressure on the saddle, and cause the center to collapse.
Another problem common to LPs with ABR-1 bridges is that the bridge posts will start leaning. Again, a warranty issue.
Stop tails can develop burrs that can damage the ball-end windings. Often you can see this damage if you look closely. This can happen with Strat tremolos, too. SRV had his tech slide a piece of plastic insulation over the string before inserting into the tremolo block. I've also seen guys do this with their Gibsons. Some of the Gibson strings use a red silk wrapping at the ball end and this can help.
If the stop tail posts are very loose, you can wrap a small piece of plumber's Teflon tape around the screws--that will firm them up. You won't need much.
I do use the Big Bend's Nut sauce at the nut slots. I will sometimes use it in the saddle grooves--a VERY tiny amount. Never ever use it on the tuning machine posts.
On non-locking tuners, proper winding technique of the string around the tuner post is key. You want to wind it so that the string locks itself around the post. Check out the CF Martin website--they have the best tutorial on string winding I've seen. You only need about 2-1/2 to 3 winds on the wound strings, I do a few more on the plain strings. And despite the fact that locking tuners are supposed to be "easy" and need no winds, I would try wrapping the offending strings like you would a standard tuner, with minimal winds.
I'm not familiar with the Grover lockers. But locking tuners can fail to properly lock; sometimes a Schaller or Sperzel tuner will get it's thumbwheel cross-threaded and it won't seat properly. You can think it's tight but it isn't. Or, it could simply be a bad tuner.
Another issue I've had is with strings. D'Addario had a batch of strings go out where the ball-end wraps were coming loose. The string would just keep going flat until the ball-end came off. They were very nice about it and sent me a bunch of stuff. Try another brand of strings: D'Addario, EB, GHS, Gibson.
I know you've checked the truss rod, but just make sure that you have positive tension on the adjusting nut.
Most of my Gibson's came with high nut action. I had to have them filed down so that the string would not go sharp in the first position chords.
That's all I can think of. If you still can't find the problem, then I would start making some calls to your suppliers: Dunlop, Grover, Gibson; and see what they say. I know these things can drive you crazy.
Good luck and let us know what you find out.
Bill
