Yeah, I hated to have to be the one to tell him that he’s way past puberty and his voice isn’t going to get any lower, but some things are best discussed man to man…
Loren
While I’m certain no one will ever WANT to hear me play a Bb flute for an hour, I’d love to be able to - the sound of Low Flutes is REALLY addictive. Don’t ever borrow one Cat, you’ll end having to own one. I’m now wishing I’d bought the keyed Aebi that Sylvain B. offered up a while back…
Loren
Got one for you, Loren. Kinda.
One of the teachers at my school decided it was time to play tenor re^%$der along with the kiddies, so she took out her no-name tenor from its decade long ziploc home and spent about two hours reaquainting herself with Baroque fingerings (the kids all play German Yamahas). It got so tight that, when taking it apart, she broke the tenon. It was the brute force rather than the swelling that broke the joint.
My boxwood Ronnburg swells like crazy and has no rings, but the repaired crack in the head hasn’t opened up yet. It probably will, being an old repair.
The German blackwood 4-key and 6-key (thread joints) are rock-stable at the tenons. Probably been that way for half a century.
Yeah, that’s why I noted that mine had metal rings. I wouldn’t think the tenon could crack with a ring, but I’m sure stranger things have happened. I have (had?) an old flute with some damage to the socket, so it’s definitely possible.
I have an old Olwell all-rosewood flute that seems to repel moisture better than just about any flute I’ve played (short of polymer). It absorbs no oil to speak of when I oil it, and seems to drip really fast when I play it.
Indeed, this I have run across in my repair work: Brute force applied to a swollen tight joint breaks the tenon.
Still though, I’ve yet to hear of a socket or tenon cracking during play, or after (while still assembled) unless someone attempted to disassemble. Interesting.
Thanks though, it’s more good reference info to have.
Loren
It’s more than possible: Remember those rings typically only fit perfectly when the instrument is at exactly the same dimensions as when the ring was intalled - assuming it even fit properly then! Any shrinkage of the socket, then leaves the wood smaller than the ring, and therefore suseptible to cracking… Even with a good fitting ring, on trad flutes they are so narrow that it is theoritically possible to split the socket further up, above where the ring is supporting the wood.
Loren
Being the owner (I presume) of the flute with that suffered damage to the socket! THAT’S WHY SHE WEARS THE ALUMINUM MINISKIRT! 
My conclusion regarding that flute is that it was “sat upon”! The tennon is also minorly damaged, I conclude that the union of the socket/tennon was jeopardized by a point loading perpendicular to the axis of the flute, in close proximity to the socket! (Often it is handy to be an Engineer) 
Loren Wrote:
Just as a point of interest in these cases: It’s actually the socket that is most vulnerable, rather than the tennon, as circles are much stronger when forced from the outside than they are when pressure is applied from the inside - think of how arches bear weight.
Be careful! Wood has roughly twice the strength in compression that is has in tension. The socket is subjected to tension and the tennon is subjected to compression. To increase the joints tensile strength, metal (or other materials, ivory being very weak and fragile in tension) rings are added to increase the strength of the socket. But, if these rings are not properly “pretensioned” or fastened tight, they serve only an aesthetic purpose!
All the Best!
Jordan
I have a mopane Casey Burns folk flute. Haven’t noticed any significant swelling, even though it does get very wet after an hour or so. Have noticed discolouration (lighter colur) of the timber where condensate has seeped out of the finger holes, and round the embouchure hole - a quick rub with an oily rag gets rid of that.
On my Sweetheart keyless in purpleheart (my first flute), I did get exactly the swelling that Loren has described. I even posted on this forum about it because it worried me a lot. It never cracked, and I reduced the incidence somewhat by greasing the cotton thread with Vaseline.
On my Sweet 6-key in Blackwood, the cork joints were very tight when I got it. I have lightly sanded them and greased them, but they still seem fairly tight - the silver rings reassure me that the socket won’t split. This flute gets fairly wet as well (I must be a wet player), but I haven’t noticed much swelling.
I misspoke; I meant to say that I’d seen a tenon that was damaged (damaged sockets, as Loren pointed out, are all over the place). Yeah, it’s the Mollenhauer I was thinking of. I hadn’t thought of it being sat upon or dropped, that makes sense.
Cracked the barrel of my Olwell blackwood pratten.
Played it for three hours, then stood it up to drain.
I had had it for two months.
Patrick accused me of flute abuse, however when
I sent it to him said he could tell from the
crack that the wood had been defective.
The upper joint (the headjoint one) on my mopane Copley gets a little tight after playing for a few hours, but I think it’s more an issue of the inside of the socket getting damp, rather than swelling. (I usually swab the flute out a few times over the course of a session.) Keeping the cork lapping well greased usually helps avoid any problems.
also have come across the problem of a tenon swelling…the one between the hands seems to swell even if I play for only one hour (new flute) and it seems that keeping the tenons well greased does actually help for waterproofing and avoiding the tenon face (so it is the very end that causes the trouble not the threading) getting stuck when taking the flute apart.
berti
I just finished playing my Mopane (JonC) for about two hours and noticed two thngs:
First, there was no swelling around the joints - well greased probably helped.
Second, condensate did roll down the tube as does my Blackwood Copley. But this is not the case with Boxwood where condensate seems to be absorbed in similar playing times.
BillG