Tom, I know this from painful experience: It may be time to bite the bullet, curb your pride, and take it to another Luthier. I have had to do this exact thing several times in my life, and it is always a terrific bonding experience.
It has NOT always ended with actual results though. Good luck resolving this...
Those elusive buzzes can be nasty. Have you checked that the truss rod itself might not be the culprit? And, of course, there's Frank's "Big Buzz List"... it's a good checklist to run-through.
Thanks for your replies.
I haven't done anything yet, but remove the strings.
Question: how low can frets go before you need a refret?
Right now the frets are around .031. I figured I could get by with that, but now...
"They do not bend in a fair curve under string tension."
Very well put.
The neck get's pretty chunky at the heel and that thought had crossed my mind. I wonder if the situation could be remedied by profiling the back of the neck.
I can say this much: from now on I'm paying particular to this when carving my own necks. I guess that's the benefit of this frustration.
Instead of addressing the neck's back profile, I'd pull the frets and level the FB in relation to the geometry of the bridge. A refret, level & re-crown/polish should take care of your problems. The low height of the existing frets, in my opinion and for my own requirements, is too low. But, that's a matter of personal preference.
The late great guitar company, Hamer, used to build the guitar up to the point it would be fretted (with the neck attached to the body). They would then let the neck, FB and body unit "de-stress" itself for 60 days. They would then level the FB in relation to the bridge. This would often result in a FB whose edges weren't parallel to the neck and it threw those not in the know. The result was guitars with unsurpassed playability and LONG TERM structural integrity. They had VERY few warranty claims citing twisted necks and wonky action.
As a personal note: I don't use the fret rocker. It doesn't allow one to perform the most important part of a re-fret: addressing the action as a 'system' in relation to the neck and bridge. I'm sure it has some sort of purpose, but I haven't found it. You can't deny that it looks cute on the bench. You can find it discussed in detail in the forum's archives. Especially read the comments by our friends Hesh Breakstone and Rusty Vance for the real deal explanation.
Best of luck with this guitar :)
I haven't used one so I may be in left field but I wonder of this is a job for one of Erlewine's neck jigs. I thought about how I would address a fretboard on a neck that doesn't bend evenly and realized that I couldn't do it with what I have available in my "tool box". It just seems like a problem needing to be addressed with the neck under string tension or, at lease in that shape/position.