I was just thinking that the silk thread idea isn't mentioned in
the "How to build an inexpensive aero engine" book, nor does GP or
Revmaster mention it.

Or have I lost that cell already?

I dunno. It was in all of the do-it-yourself VW manuals "back in the day"
and genereally mentioned #50 as the thread size. I had presumed that #50
was a fairly stout thread, however a post by Highflyer in this conversation
leads me to wonder and a breif www search was less than informative...

Peter