Muv made a good video about how to thread these machines:
http://www.youtube.com/watch?v=H2tiiZ51J7g I have learned a lot more since this post was new. Now I routinely take apart the tension. I clean the dead oil off the springs etc. Then I rebuild. They adjust so much easier. This manual has good info:
http://www.tfsr.org/publications/tec...achine_manual/ I recently set one up with a hand crank & heavy thread - WOW it now sews through about anything.