Originally Posted by Freakn
1/4" NPT & BSP are that close it usually doesn't matter. A bit of thread tape or liquid sealant is all it normally needs.
OK, just wanted to bring this back up for an update.
I got in a couple 1/4 NPT schrader valves (they come with teflon sealant on the threads) and tried screwing them into a couple extra G 1/4 extensions I have and it's a no-go. It won't go in not even 3/4 of a turn before getting very tight to the point if I were to force it more I know I'd be damaging the threads to one or the other or both, and it's nowhere near the point of being sealed. I can blow air through it easily. It almost sounds like a whistle.
Anywho, I went ahead and ordered a couple Koolance G 1/4 Male to NPT 1/4 Female adapters from PPCs. Wish I had thought to do that before - didn't even think to look for such a thing - as I could have gotten them from FrozenCPU and added them to an order I placed there a couple days ago (grabbed the Monsoon Hardline kit and a bunch of fittings) and would have saved on the shipping and the wait.