I'm not sure if it's because of irregularities in the 2 pieces of pipe, Too much interference, not working fast enough or what, but it went on 9" and came to a sudden and abrupt stop...
So, now I'm gonna resort to brute mechanical force, I just ordered a 10' stick of 1" allthread rod(which will be here next tuesday), run it through the semi-assembled pipes with nuts and washers on both ends(weld the nut to one end) and I'm gonna put a 3/4" drive impact wrench on it and see if we can't just muscle it together.
I will grease the threaded rod thoroughly to remove as much friction there as I can, and If my calculations are accurate, 500ft/lbs of torque on the wrench should be several tons of compressive force...
If it doesn't work, I'm starting from scratch with new copper and a slightly larger id steel(if I had known how far off NOMINAL specs were going to be, I would've used the 1.135" id pipe to begin with) slather the copper in green loctite and be done with it...`