On Dec 16, 1:35*pm, coloradotrout wrote:
OK.. this has to be basic.. but I don't know the answer, so I'll ask.

On door latches there are 2 parts that extend out from the door (which
go into the strike plate). *Both can be presssed towards the door.
One is larger in diameter and is the part that latches inside the
strike plate when the door is closed. *But there is another, smaller
diameter part that rides right along side the larger one. *What is
that for? *If you push hard enough, that one can also latch inside the
strike plate. *Is it suppose to?

I have an exterior door that does not fit well and leaks air. *I think
it needs to be rehung, but if I press hard enough to get that second
bar to latch, it's better.

The second bar is "behind the main striker plate. I believe its
purpose is to keep you from being able to use a credit card from
opening the entire latch. If you try to push the card slowly into the
tapered side of the door latch, from the outside, you can get the
latch to retract into the door. But the separate bar does not push
back gradually, so you can't get the door open.