basically drive the ends into the sleeve I've ordered until it's the correct length while insuring it stays timed (line up the holes on each end of the shaft ends), then tack weld at 6:00, 12:00, then 3:00 and 9:00 using my wire feed MIG and verify it is still straight, then crank up the amps and fill in the space between the tack welds, letting it cool between each 90 degree section to avoid warping the shaft.
Using straight CO2, I don't have Argon mix...