hemp/thread vs. cork

[uillmann]

Very well said, Ted. I don't know what size you use, but here is a pretty good link describing some linen threads.

http://www.threadneedlestreet.com/linthrd.htm

[Ted]

Linen is sized by lea. The usual shoe thread is 10 lea. This is the same thickness as GHB "hemp", which is linen. I use 16 or 20 lea thread. 20 lea yields a thread twice the length as the same weight of 10 lea thread. Cannabis hemp uses a metric system which is different from linen. 10 Nm in hemp is the approx. the same size as 16 lea linen thread. The threads I use are single ply, so their designations would technically be 10/1, 16/1 or 20/1. Sewing threads are made up of single spun threads plied together. A 80/3 sewing thread would be twisted up from three strands of 80 lea thread. A single ply of 80 lea thread is 8 times as fine as 10 lea thread.

[Cathy Wilde]

Not a fan of cork, even on flutes. Wet cork on thin tenon wood bothers me; I've seen way too many hairline cracks at tenons and I blame the combination of wet/dry/stress. I do like being able to use several thicknesses of silk and linen thread to "fine tune" as described above, especially on slightly warped tenons. In my experience with 3 boxwood flutes and a boxwood set of pipes, a little warp is pretty much a fact of life.

[Ted]

Not withstanding Terry McGee's comments about thread wrap for flute tenons, I have seen a number of corked flutes with cracks in the tenons. Interestingly, many of these cracks are beneath the place where the cork is lapped or butt jointed together. That cork joint is a weak spot in the tenon. As weak as cork may otherwise be, it is even weaker where the ends of the cork come together so the timber gives way at that point. A thread wrapped tenon has no weak spot and may help prevent cracks.

[Cathy Wilde]

Interesting insight. I hadn't zeroed in on a higher incidence at the seam of the lapping, but I've seen plenty of fissures in corked tenons (including one of Terry's!). IMO, it seems like tenons and barrels are flutes' Achilles heels. Seems logical to me; they're always being twisted around and probably have a fair bit of longitudinal stress, too. They're thinner but supporting the thicker-walled weight of the rest of their respective parts. Hammy's metal tenons make sense, and cork might be OK there, too b/c it's not sitting soaked on thin-walled wood. Just my .01

OK, back to the happy place. Yay pipes! And thanks for an interesting discussion.