heres the rub, I have an M&E polymer early model 7 or 8 years old, I was going to sell it, as I found it quite hefty, but the sound is FAB, so it will be my home and travel flute as I get away a fair bit as a commercial photographer.
Now the question I have is regarding the lined headjoints of flutes from current makers, Olwell, Hamilton etc, I know there are many more and that half lined options are available, in my case I have the chance of a fully lined Hamilton in Blackwood, my concern is that from various sites and sources the lined heads are good in as much as condensation and moisture dosent come into contact with the wood of the head and tuning slide, but that the wood can dry and crack, I am guessing that this is due to not being able to oil the head because of the lineing, so is there anyway of stopping your lined head from shrinking due to the drying out process, as it seems odd that a flute with a lined head from a top maker could crack without you at least having some control, something you would have with say a Burns or mcgee flute that the head could be regularly oiled as they are unlined, or am I missing something here is there a way of getting oil into the back of the head joint, as i’m thinking that oiling the outside of the head would have little or no penetration.
I’ve had lined heads which I’ve oiled externally, and never had a problem with them. I’m pretty sure if you leave the oil a day or two it will get in there.
having not seen a wooden lined head, does the lineing fit the wood tube very snuggly so there is no gap between liner and wood, my M&E is tight sandwich, I know its polymer and a totally different as theres no moisture issues with PVC, Terry Mcgees very informative site is packed with info regarding the pros and cons, as far as I can tell Terry only makes the un-lined models.
I have an unlined Hamilton and two unlined Murrays, so there are other options out there. My Olwell is lined and I find it “speaks” a tiny bit more clearly, but I also like my unlined Murrays a lot for other reasons.
I’ve had lined and unlined flutes over the years and have seen both kinds with cracks in various body parts, heads and barrels included.
I suppose that doesn’t help much, eh? Sorry … Bottom line, I’d say just take good care with humidification, stress avoidance (try to let the flute hang out at room temperature a bit before playing it if it’s been out in the cold), and moisture maintenance (i.e., balancing oiling and regular playing/swabbing), and I think that’s the best you can do.
Oh, as for oiling a lined headjoint – I just make sure I oil the socket and around the blowhole as well as the end of the socket. So far so good.
It seems people tend to think of oil as a moisturizer because it soaks in there and gets into all the ridges and divots and secret hiding places and makes the flute sound good like when you’ve been playing for an hour, but personally, I think of oil more as a waterproofer.
IMO, the logical way to maintain even moisture balance throughout the the wood’s entire cellular structure is to keep the flute between 55 & 60% humidity (boxwood seems to prefer nearer 50) and then just play the darned thing regularly; the best way to keep it from getting too soaked is to oil it and swab it out when you’re done playing!
Just my $10,000.02 (figuring that’s about what I’ve spent on these goofy things over the years) …
if the hj is stored at 50-60% rh, it is immaterial whether there is a lining or not. i have had flutes w/ lined hj that were over 100 years old with no cracks and flutes less than a year old w/ unlined hj that cracked.
I have two lined flutes, but have never been comfortable with them, largely due to the persistent rumor that lined flutes can crack more easily than unlined flutes. Oh, I have tried to convince myself that such a rumor amounts to little, but it is a hard rumor to ignore, frankly.
i believe that would be true if you didn’t store the hj’s at 50-60% rh. theoritically differing rates of expansion/contraction are then supposed to dictate (as denny described).
yet, prior to properly storing flutes, which is not a big deal at all, my experience with several flutes indicate that is not as big a factor. in fact, unlined and partially lined hj’s cracked more often than did the lined in an area (new england) with big changes in climate. As example, unlined sweetheart flutes made in new england cracked as did a new seery, while an old german, an old french, and old english flute , all lined hj’s did not. figure that one out.
since i have been properly storing flutes, which i do regardless of lining, it is a non issue. no cracked hj’s.
Bottom line, I’d say just take good care with humidification, stress avoidance (try to let the flute hang out at room temperature a bit before playing it if it’s been out in the cold), and moisture maintenance (i.e., balancing oiling and regular playing/swabbing), and I think that’s the best you can do.
Once again, rama says it so much more succinctly. 
…and I used big words…