SSP project regulator change

[bigjeffb]

I'm revisiting my SSP rebuild after it sat in my basement for two years. I got a brand new regulator from ACE because, and I salvaged the elbow and the orifice from the old regulator. I also go a 3/8 flare x 1/8 NPT to connect the elbow to the end of the new regulator. From scouring the web, that is what I have found I need.
The problem I'm having is that when I go to attach the new fitting to the elbow, I can go maybe 1/2 a turn, and then it stops. And I mean I would have to FORCE it to make it go any further. It isn't cross-threaded as far as I can tell. So naturally I don't want to destroy what is becoming a more and more difficult piece to find. Any suggestions would be greatly appreciated.
I prefer to use the gas assist, and I already have a new 5 lb tank that I may as well use.