Shaw 335 Always Out of Tune ... please help

I have an '82 ES-335. Beautiful tone from these Shaw PUs. Blonde (drool emoji). Love the neck profile so much, I new I'd buy it before I plugged it in.

However, I find that it often sounds out of tune. It's not a simple intonation of the bridge. And it's not just getting detuned from bending (of which I do little).
I'm playing big jazz chords, with 12s. It really seems like a given note can be very sensitive to how it is fretted. Played by itself, it may be fine. When gripped as part of a chord, it's off. My action's not terribly high (.080" @ 12th).

These super-low railroad tie frets, on the other hand ...
They seem likely to wear in a manner that would do just this. My Jazzmaster with vintage Fender frets (narrow), on the other hand, always sounds perfectly in tune.

Does this seem like something that a refret / PLEK would address? What's a good way to evaluate that? Anyone know of any good luthiers in the Boston area for this?

I've had this guitar for ~ 4 years, and I'd like to make this marriage work.
thank you.

Before you do a re-fret, apply some lube on the nut. Since 10's are the normal gauge string on most 335's I wonder if you're getting sticking or friction in the nut. Have you ever tried to experiment with 10's instead of 12's? Also, have you stretched the strings vertically to speed up the break-in period? There are many other suggestions folks could give, but try the easy ones first.

@Aloha, The guitar came with 10s. I had the nut filed when I switched. I use nut lube when I change strings. There may be case to be made that strings suffer in intonation when they get quite old, but I think I’ve experienced this with both new and old strings.

The first question is whether your bridge is properly adjusted to intonate your gauges.

If you can't say, "Yes, I have checked and verified that," you may find that all you need is a quick visit to the shop (when the shop is open to visit).

dm_cambridge_ma said:

@Aloha, The guitar came with 10s. I had the nut filed when I switched. I use nut lube when I change strings. There may be case to be made that strings suffer in intonation when they get quite old, but I think I’ve experienced this with both new and old strings.

Click to expand...

Next possible cause could be pressing down too hard on the strings (thicker strings have higher tension). Can you tell which fretted string is out of tune? How does it sound when only that note is played?

It could be that the action at the nut is too high. So when you press the strings down in the first position they won’t play in-tune. Another deal is that Peterson Tuners recommends setting intonation at the 5th and 17th frets, not the open nut and 12th fret. Nut/12th will only play in tune for the first 12 frets. Above that will be outa-tune...

I had a nice '63 335 that had a weak neck joint, which affected tuning stability.