Terry McGee’s argued very convincingly that hemped tenons can “strangle” (crack) flutes over time, by not expanding enough when the wood does. The simple and convenient fix he suggests is to use cork instead, which besides being more pliable (and therefore self-season-correcting) lasts much longer between applications.
So, why do we pipers still use hemp? Is it because reeds are so low-maintenance that we’ve got loads of time to kill? 
Cheers,
Mick
There is a world of difference between a wet joint and a dry one. I’m not totally convinced by Terry’s arguements. I have lutes with both threaded and corked joints/ Properly done thread seems safe enough. For pipes, I would be careful of dry joints using cork. It’s fiddly to get a good fit that will not shrink and swell in a dry joint. .
Bobl
I like silk. It lasts much longer than flax, and the extra fine twists that are available make for a more exacting fit. It is not a fluffy as hemp, but a light wrap or two over the hemp will protect the hemp from fraying. Cork is fine if it’s just the right fit, but so often, it is not. With combing, if it is tight, I can remove a little, if it is loose, I can add a little, and I can do that in a snap with no special tools. I experimented with cork, and unless I sanded it down to size on a lathe, it is not handy to adjust it, say, between sets, busking, or traveling. Unlike flutes, with their wood/cork/wood joints, a corked joint in a tubular brass fitting can compress the cork permanently, and it is usually not “self-season-correcting” as dependably as one would like.
Thoughtful feedback, thanks! I hadn’t thought of the differences between wet and dry joints, or between brass-cork-wood and wood-cork-wood combinations.
I’m still tempted to experiment, though; I really like cork. Sanding corked tenons on a lathe doesn’t sound that inconvenient to me, and is it really that hard to keep cork from drying out, if you keep it well greased (which is necessary anyway)? I would expect greased cork to remain reasonably spongy across seasons, at least on joints you take apart after each use.
(Hmm, maybe that makes cork a better candidate for tenons you store separated, than for ones that are supposed to remain joined most of the time? E.g., good for bass-drone crooks but not so much for mainstock connectors?)
Back in my days as a band director, the only compressed cork I recall encountering was on instruments that hadn’t been played in many months or even years. But of course that experience all involved “wet jointed” instruments, mostly flutes and clarinets.
Regards & thanks,
Mick
I vaguely recall Tim Britton using cork on the stock (?). I have a couple of Hammy Hamilton flutes, and he uses cork. It’s a super tight fit that requires cork grease. Peter Hunter recommended cotton thread. He mentioned that using polyester thread can damage the wood.
I feel strongly that cotton thread is the only man for the job…especially in our wildly-swinging climate. BillH has …ahem…waxed eloquently on the hows and whys. A search should deliver his postings.
I would love to convince the locals to give up the super-heavy/super-waxed “hemp” (it’s not really hemp) that so many use (from GHBs no doubt). I worry for their instruments.
T
cork stinks for pipes. mouth or bellows blown. just trust me, & take my word for it.
Back in the 80’s, I bought some twenty or thirty odd types of natural fiber thread, and none could compare to silk for anything other than bellows stitching, which, for various reasons, prefers Nyltex. Silk beats all others, hands down. And, for what it’s worth, it comes in any color you can imagine, not just boring yellow. I always considered “hemp” a piper’s euphemism for a 12/2 reverse twist cobbler’s flax, (except for bag sewing, which might be 7 cord linen instead of nylon.) I never actually analyzed the waxed yellow stuff that is commercially available to GHBers, but I always used a #3 Barbour’s Irish linen shoe thread for reedmaking, which is flax, not hemp, and it is cheap as dirt if you buy a lifetime supply in a large spool. Sadly, hemp has been rather expensive since the late '60’s, and from what I understand, is not commercially available for a lifetime supply except in California, where that which is available is suitable for wrapping all proper joints other than those of the bagpipe. Flax is a considerably longer fiber than any cotton, which is why it is used for shoes. I found all of the cotton to be inferior to good quality linen or even ramie, although some brands of ridiculously high-priced mercerized high-twist sea island cotton is pretty good stuff. But for for the natural fiber purist, silk wins every time, (unless you have ten thousand dollars to wrap your joints in black widow or yellow orb.) Don’t wrap your joints in synthetics - that’s like using teflon plumber’s tape. Ick!
I’m enjoying this thread (sorry) and would like a suggestion on what size silk thread would be best for drones, regs and stock? Thanks.
Thread weight, denier, tex, etc. gets a little confusing. The first is the number of filaments in the cord, and the second is the number of cords in the thread. This is expressed similarly to a fraction, like 50/2 or 40/3. ( A 40/2 is 2/3rds the weight of a 40/3. ) There are lots and lots of sizes, and then you have various twists, etc. which are specifically designed to maximize their behavior in different kinds of specialized machines. Silk filaments are very fine compared to flax, so there are more filaments per cord, or more cords for a comparable thickness or weight of finished thread. For a protective wrapping, a kimono thread like YLI100 or is fine, but it is probably too fine to wrap the whole joint. You should consider getting a sampler, which will cost about 30 bucks. You probably won’t really need any more, because you can use the heavy stuff first and then use the light stuff over it to fine tune the wrapping. I think a tight wrapping of a fluffy thread like linen or ramie followed with a single covering of very light silk is a reasonable way to go. In the overall scope of piping misery, the combing material may be the most trivial concern of all, but it isn’t completely irrelevant. If you want to try learn more than you want to know about threads and the various ways they are measured, here is a link to a page that might serve to confuse you completely.
http://designer-entrepreneurs.com/blog/illustrations/Thread_Sizes.htm
Mark; no way am I going to sit there combing the golden hemp.
Uillmann, could you flesh out your preference for silk over cotton, please?
T
Cork is ideal for wet joints that are stored dis-assembled. Not good for dry joints and/or those that normally remain assembled, since the cork dries out and also stops springing back - thus cork is not preferred for pipes. A cork joint that remains assembled for a long time will lose it’s grip/compressibility. Woodwind instrument repairers deal with this problem often, I’m told.
Tenon compression is something that can occasionally occur, but IMO it’s not particularly important to us. It’s highly unlikely unless the timber walls are thin relative to the diameter, which in a set of pipes only really happens at the regulator cap ends and possibly the chanter foot - both places where a bit of compression is unlikely to do much harm. On the other hand, in a mid-bore joint like that of a flute, where the tenon walls are very thin, it could have a noticeable effect.
I suppose it is only because silk has longer fibers and does not seem to fray as easily. There’s nothing wrong at all with cotton, but most cotton thread is made of very short fibers. That said, I do like the fluffiness of cotton and fine flax, and when it is fresh it works just fine, but once it starts to disintegrate it can become a mess at some inopportune time, and I would prefer to replace it. And the fluffier it is, the quicker it will compress too much for a good fit, and the tighter the twist, the less fluffy it is. Silk doesn’t have that same fluffy quality, but it seems to last longer. Dental floss probably doesn’t fray as easily either, but I have never liked floss on joints - why, I don’t know. FWIW, my pipes currently have whatever cheap cotton from the sewing box on them, haphazardly whipped on to get the job done in a hurry. If someone is lucky enough to have really good pipes with no rough edges anywhere, and they are all seasoned and settled, it probably doesn’t make a bit of difference as long as it fits well. I was always one to repeatedly pull things apart in an attempt to tune the reeds, so some joints would seem to fray regularly. On the other hand, some drone joints I wouldn’t even see for years. And if I was feeling lazy and a tenon was a little loose in the mainstock, I might just rub it quickly with a little wax to make it stick, but my occasional lax attitude about my old set is likely not the greatest benchmark for fine fettled pipes. The true traditional purist would likely favor a very fine Irish linen. Maybe my preference for silk is all just about my personal, arbitrary, ill-founded snobbishness. Anyway, the esteemed professionals out there probably have more well-reasoned opinions than a dilettante like me.
http://designer-entrepreneurs.com/blog/illustrations/Thread_Sizes.htm
Unwaxed GHB “hemp”, which is actually yellow dyed linen, is OK on larger joints. The waxed stuff is produced for pipe joints that get wet. It lacks compressability, which is what you want in dry pipe joints. Real cannabis hemp and linen have long fibers and are stronger and wear better than cotton. The fuzz helps with air-tightness in a joint, without needing to be overly snug and hard to move that you get with a very smooth thread. I use hemp which is only half as heavy. as the GHB stuff. I get much finer control of the snugness of the smaller joints. I may re-wrap the outside layers every two or three of years with regular use. Not a very time consuming process. I also black-wax the first few inches of thread to attach the thread to the wood and cover with raw hemp. Hemp must be tightly wrapped to not unravel during use. Atightly wrapped joint will not easily fray. If a lot of layers are needed, I may add bees’ wax to the bottom layers, leaving at least three wraps of raw hemp on top for compressability. A tightly wrapped joint can easily have more hemp added or some removed to adjust for the seasonal shinking and swelling of the wood. I add cork grease to the outside of wraps that contact metal tubing for the seal. It lasts for years. Steer clear of using plumbers’ tape or synthetic threads. I sell the fine hemp and black wax needed for this. PM me for more info. Silk is usually very fine and requires lots of time to wrap, unless you are wrapping on a lathe. Single spun hemp and linen are what has been used for centuries on pipes with good results. No need to re-invent the wheel.
Very well said, Ted. I don’t know what size you use, but here is a pretty good link describing some linen threads.
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.
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.
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.
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.