Subject pretty much says it all - After i realised that the cork in my flute was pretty much falling apart, i thought i’d start looking around for a replacement to put in there… but i’m not sure what size to get. I’ve looked on ebay & there are plenty of “Wine Making” corks available… i assume that these will be OK? So i’m left with the question of size.
Many thanks to all who can help with this. 
Jinian
many of the “corks” used in bottling wine are now synthetic
ya need to find a real cork
the standard 750ml wine bottle cork will do (it is a bit big, you will need to sand to size, while staying round)
two buck Chuck is still using real cork
…more like 3 now…
if this makes no sense at all, don’t worry about it, isn’t worth explainin’
What’s wrong with synthetic cork?
Yes, what Denny said.
Maybe not. You didn’t mention what type off flute you are playing. Cork size depends on the bore of the flute. Assuming however that you have a 19mm bore, a standard #9 cork (15/16" in diameter to start) will usually do the job . That cork is meant to compress to fit a bottle that generally has an 18.5mm neck. That is a fairly standard sized wine bottle cork. You probably don’t want to compress the cork as much in your flute as you would to bottle wine. Champagne corks seem to be smaller, #8 corks (7/8" in diameter to start).
You can search the net for info on wine bottling supplies. You should be able to find a table of standard cork sizes there. I posted a link to one here a while back but I can’t seem to find it now.
But really, go buy a bottle of wine and see if the cork fits. If not, go but another bottle of wine, etc. Share the experience.
Feadoggie
forgot that I wasn’t a wine snob anymore 
you might be able to thread wrap the old one…
'course we’d need to go on for a couple of pages about different types of thread & grease
we can do that 
Can we go on about the tonal differences between natural cork stoppers, synthetic cork stoppers or composite cork stoppers too?
http://www.bigio.com/stoppersandcrowns.html
He’ll custom-make ones for simple-system flutes, too.
Ok, I will be bold. Why not wooden dowel like in a whistle? I know there is a reason.
WoW!! LOL… some great replies there, and i thank you all for your time & input.
With regards to the bore size, i don’t have the tools to measure the size down to the micrometer but using a simple tape measure, the bore across the top of the headjoint is… approx 18.5mm.
I REALLY like the bigio crowns & stoppers, and although i probably won’t get one yet, i’m certainly keeping that in mind as an option in the future.
I didn’t realise either, that the crown piece was threaded… for some reason i thought it was “screwed” in but having a closer look just now i see that it’s threaded, and the thread, while still there, looks as if it could do with replacing. Again something that i know nothing about but would like to learn more as i have a small “Grey & Sons” fife that i’d like to restore at some point. It plays reasonably at the moment (given my lack of skill etc) but i’m sure that it could be better.
So all thread & grease topics & hints are also very much welcomed!!
Many thanks once again to you all…
Jinian
I found this on ebay UK, any good? It says a 4mm bore??? And i’m not sure what 19mm OD means, but i’m assuming that it refers to “Overall Diameter” or somesuch?
Confused, but having fun!
Jinian
That auction is for a standard stopper for a Boehm metal flute. 19mm is the outside diameter of the cork. 30mm is the length of the cork. I would think that 4mm is the size of the hole in the middle. That’s fine if you are talking about a Boehm flute. Really, it’s overkill for most wooden flutes. Buy a bottle of wine and use that cork. Most wine bottle corks are long enough to make two stoppers provided you don’t bugger it up with a cork screw. I get crisper tone from white wine bottle corks as opposed to the husky tone from reds but your results may differ.
Ok, flute stoppers are not fixed into the flute head bore. They are generally fit firmly by compressing the material. Cork is ideal in that regard. It’s compresses well, is durable, holds its elasticity and resists moisture as well as some of the nasties that warm, moist conditions can lead to. Same for wine. Remember cork comes from the bark of cork oak trees.
Is that wood then? Maybe just a special type of wood. Other woods are not as elastic as cork but they swell and shrink none the less. If they would shrink in a flute bore they might fall out. If they would swell they could remain there forever or, worse yet, cause the flute to crack perhaps. Just some thoughts.
Feadoggie
I’m after one for the Low D Irish flute, but as i also play the Boehm it’s kind of handy to know as well… seems a bit odd to have a hole in the middle though, is that standard for Boehm flutes? I’ll have to unscrew mine & have a look.
Really, it’s overkill for most wooden flutes. Buy a bottle of wine and use that cork. Most wine bottle corks are long enough to make two stoppers provided you don’t bugger it up with a cork screw. I get crisper tone from white wine bottle corks as opposed to the husky tone from reds but your results may differ. >
Feadoggie
LOL, i’ll make you right… i don’t drink wine but i’ll buy a bottle & give the contents to someone who does and make sure that i get the cork. I quite like the sound of a Husky tone, so perhaps a good red will do the trick?
Thanks for the advice.
Jinian
I’d go with a really wimpy white,
in hopes that the sound will run out the other end to get away
M, have you tried one? I’ve got a long-suffering crownless keyless and was thinking this might be a fun experiment for probably about the same price as sending a flute back to Ireland, etc., etc.
Thanks!
Yes, the hole is standard on Boehm corks. It’s what the screw runs through that the crown attaches to. See “Head Cork” here: http://www.fluteworld.com/index.php?action=strona&wart=13#Head%20cork
Often the cork is faced on one or both sides with silver disks; I suspect to help keep it a little more dry and also to help it stand up to assaults by tuning rods and low-register-obsessed flute players.
Bohm flute corks as supplied by music stores/woodwind parts suppliers are not suitable for Simple System, cylindrical head flutes - they are too small for Concert ones, at any rate, and then you’d have to block up the hole through the middle (not that that’d be difficult).
When I do up flutes, to replace defunct or missing corks I mostly use the modern plastic corks from wine bottles (the more solid rather than the foamy-centred ones are best) and cut them to size by gently heating up the male tuning slide of the flute (the projecting part of the head liner - and no, I haven’t cracked or singed any heads thus…) and then pressing it down on/into the cork to cut off the excess diameter and get a snug fit. You’ll need a dowel to push it back out! Then cut to desired length, use a hot skewer to make a hole in the back end if it is to go onto a crown/stopper adjuster set-up (doesn’t sound like this one is?), seal the front face by heating a knife blade and smoothing off the end (best done with it inside the head - use the liner tube end to guide)… or you can make a metal face plate from a suitable coin and glue that on… All of which is much easier than sanding down an oversize natural cork, I find. I haven’t yet come across wine corks (brand new or recycled - and I’ve got a few of the latter! ) that are just the right size to use without down-sizing. I can’t detect any discernible tonal effects/differences.
Remember to grease whatever you use well before final insertion!
Yeah, I’ve tried two: Back in the day, I had a wooden Boehm headjoint by Terry McGee. With the Bigio stopper/crown, the flute felt more resonant and ringing. In the end, I put the original cap and cork assembly back in, and a repair guy added a few ounces of weight to the assembly, which made the headjoint darker and more resistant. The differences were quite pronounced, but neither was objectively better–just a matter of personal taste.
I also tried a Bigio stopper on my Copley & Boegli (although without the perforated crown), but the effect, as I recall, wasn’t substantially different from the original set-up. With the Bigio stopper, the flute was a bit more free-blowing, whereas the original stopper (also delrin, held in place by O-rings, but a bit heavier and without a groove on the face) made it feel a bit more resistant.
I’ve periodically tried my flute without the crown, but then it’s too free-blowing. However, after some deliberation last year, I revved up my drill (I can’t believe I’m admitting this in a public forum) and put a small hole through the end cap. Pleased to say I’m delighted with the results. I’d say give the Bigio set-up a whirl! (What’s the flute?)
you nut! Well FWIW, you sounded pretty darned mighty last month, so hey!
It’s your basic quintessential blackwood Murray, a barking little flute with lots of resistance AND resonance; probably the liveliest thing I’ve ever played. I lost the crown some years back and have never replaced it. I’d be curious to see would happen with the Bigio setup – I wish they weren’t so Boehm-looking, but hey, you know. Thanks so much. And again … you wacko! XO 
That’s why they invented wood putty. (Naw, it’s been about six months now, and no regrets.)
As for the Boehmisch crown looks, the blackwood ones aren’t bad–looked fine on my McGee HJ. (I sure wouldn’t put a zirconium crown on a wood flute!) Or see if Dave Copley could fit you with one of his delrin ‘corks’ and a blackwood crown. It’s a very similar design, minus the hole. But I can talk you through that part. 
Or you might even see if he would put a hole in the crown–it would save wear and tear on your driller. 
OOOH, if Bigio’s are flattish like Dave’s or the traditional stopper, I’m happy! Thanks so much! Home to the Vernier calipers I go (after Ri Ra) !