Bike Issues

[Skunks]

I was fiddling around with the derailler, having removed it from the frame and trying to get it back on. After removing the chain from the front derailler to give myself a little more room to move it around, I got it positioned so it'd screw back in. After a few turns, though, I couldn't screw it in further. I've been unable to get it fully screwed back in; I think I've got the angle wrong, or something.

However, in playing around with it as it is, it seems to shift better. The alignment of the upper pully seems better, and the chain <a href="http://skunko.damnsw.net/bike-close4.jpg">isn't touching the support metal for it</a>.

However, the derailler's hardly screwed in; it has a good cm of <a href="http://skunko.damnsw.net/bike-gap.jpg">open threaded-metal</a> visable from above. I haven't tried putting much force on the allen wrench, for fear of munging the threads (if I haven't already), and I don't really think it's rational to just leave it as is.

So, is there some trick to screwing it back in? And where should I be looking for bentness?

For the record, wolf, the whole drivetrain looks to be Shimano. It's a Trek 830, with Shimano logos on both the derailler and the pedals.