[Chris P.]

Personally, I wouldn't weld the rod end. Not knowing the carbon content of the steel, I would be worried about making it too brittle. Chances are, it has plenty of carbon in it to do that. It looks like you have plenty of room to take some material off the end of the arm there. If you have to, grind away the weld holding that threaded sleeve on, pull the sleeve out, cut the tube short - as close as you can to the other tube (even make it flush with the edge of the other tube if you have to), then reinsert the sleeve and weld it (or braze it even.) It seems like that should give you all the threads you need...