What's lovely about finding a chewed up chainstay, you ask?

It solves a longstanding mystery, which is something I don't get to do very often.
As detailed passim, my Litespeed
Once upon a time I used to just turn my bikes over when I wanted to work on them. Then I discovered workstands.has been causing me grief on and off for years because it wouldn't shut up with its ticks and creaks. I've tried a long list of remedies, and been through countless cycles of short-lived success.
Its story begins in 2000, when I bought it from the States on mates' rates for being a cycling journo, or close enough. Our first years together were trouble free. We shared a lot of happy miles. It had gears then, gripshifers on straight bars. Later I switched to
caressable Dura Ace downtube shifters.
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The aftermath:

The holes I had drilled later sprouted cracks, which as you might expect caused their own screech. This scar is a reminder of my stupidity.
When it was around seven I converted it to single speed, seduced by the visual and mechanical appeal of a simpler drivetrain. Initially clunky,
CLUNKYit then offered up a magic gear (three cheers for 44x17!). Later it dawned on me that this is when our troubles began.
Clearly a chainring arm has been rubbing against the chainstay. How on earth could I have missed that? Because the surfaces only met when the bike was under significant strain when it was being coaxed uphill, that's how. NACF HQ is nestled in the the High Weald rather than the Fens, so here we are.
Until yesterday's denouement, a word I now feel committed to using after dropping in passim, suspicion has most frequently fallen on the bottom bracket. I removed it so often it became a running joke.

Indeed, the bracket has been trying to tell me something all along. (First the headset/forks had something to say, but that's a different solved case.) It's too short.
Paging a metallurgist: on those occasions when the chorus* of complaint didn't start until after I'd been riding awhile, is it possible this was because the frame also got a tiny bit bendier as it warmed up?
*not a pun, as it has a Record crankI'm also guessing that with every BB reinstallation I don't tighten the crank the same exact amount, leaving it a very slightly varying distance up the spindle – which could help explain why there were quiet periods.
Judging by the horrible picture near the top of this post you'd think I'd have noticed the scrapes a long time ago. Perhaps I did, but it never occurred to me there could be so much flex. Hiding behind the chainring it's easy to ignore then forget about. I only got a good look at it because I finally decided to minutely inspect

that part of the bike in search of cracks, which thanks to my love affair with titanium are now something I have a good deal of experience with.
Fortunately I had another bottom bracket in stock, 103mm instead of 102mm. Don't remember how 102mm was settled on in the first place; possibly someone at a shop told me way back when and that was that. The chainline obviously worked.
Anyway, I put the 103mm in, hoping the extra millimeter would make a difference. It made a LOT of difference.
This would be the after picThen it struck me: the new bracket is JIS, meant for the Sugino in my life. The Campagnolo crank is ISO. According to Sheldon Brown, on the same size spindle this should have the crank about 4.5mm farther out! No wonder.
It works, and surprisingly isn't way out of kilter. I'm kicking myself retroactively, but otherwise very very happy.