Same thing happened to me! Dammit! I was thinking of re-tapping the connection with the 7mm x .5 threading, but to do it "correctly" you have to drill it all out and use a replacement 7.. x .5 insert and I don't think there is enough depth in the connection socket to do it without damaging the power connection. I was trying to figure out if the threaded components can be detached from the head but it looks like its cast on there and I am afraid of breaking it if I try to take it apart.
There are also some "thread repair" kits which are basically an epoxy you mix and then apply to the threads, looks like it's just JB weld, maybe with a different composition.
For now, I've managed to fit a 510 - 510 adaptor on there so I can still vape, but it makes the
mod look pretty ugly since the
tanks protrude out a bit.
Been thinking about just ordering a replacement control head and eating the $75 or whatever... or just go for broke and get a Provari!
Let me know if you figure out a good fix for the 510 threading!