Bill D, I have a recorder with a cork joint that isn't tight enough. So far a piece of Scotch Magic Tape has fixed the problem.

Have you kept the corks greased?

Now, about the trick of a few windings of thread - how do you keep the thread in place? So it isn't pushed down when you put the sections together?
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Sunday my friends were over, playing early music. Halfway through the evening, I glanced at the back porch next door. Their drunken, troubled uncle was sitting in the dark, listening to us play. He told me later that the music was "soothing." Nice.