I'm looking for some suggestions to get my Iatty SS mouthpiece to screw on the top cap, it only screws on about half way, and I've tried two ss mouthpieces so I'm pretty sure it's the cap threading. It seems to hit a little rough patch when screwing in, gets through it, then just stops. The Delrin piece screws in flawlessly. I've tried everything I could think of or find short of breaking out some tools, don't wanna ruin it. Anyone think boiling one piece and freezing the other might work? Any suggestions will be appreciated.