Maybe a link to this site will clear up what it is I'm trying to do. I have built the entire burner, and it looks fine, with the exception of the MIG tip. And I mistyped earlier. I'm trying to get the tip into a 1/8" nipple, not 1/4". The tip just does fit inside, bit slides through. I can't find that connection that's listed, so I was wondering if there's another way.
It's the section half-way down called "Guru's Burner":
Gas Forges : Building Your First Gas Forge
The big question that would make this a little easier is, what is the temperature of the burner at that upper end? Is it relatively cool compared to the 2000F inside the forge? By cool, I mean around 200F. I'm the first to admit my lack of experience. That's why I'm counting on you experts to help me not screw it up. Thanks for the help, guys. I know I'll eventually get this done!