Quote Originally Posted by Waterlogged View Post
The difference between NPSM and BSPP is a minor change of thread O.D. and 1 TPI. Since all the threads on everything we use are so short (with the exception of the plastic Swifty barbs), it makes no difference as each will thread into the other. . .without problems. The difference in diameter is inconsequential.

As far as the lip on the GF, I think the o-ring on the BP should seal on that area in the T3 when installed.
Yea i understand that, but there still is a difference. I could feel it threading into a Swiftech rad. I had no leaks, but still put those adapters in.

The only point I was making is why go and spend 3 dollars a fitting when all your really trying to get is the thick o-ring on those adapters. It would just make more sense to go and buy that o-ring and mount it on the compression fitting.

Another thought though, with that collar CM pointed out, how well do those ghost fittings seal on a non recessed hole? Does the whole fitting stick out by that 1.3 mm?