Hey Benjamin! After looking at the file, I think you can set the collision type to box. Spikey is right that collision objects are better with some thickness, but there’s no need to subdivide if you’re not using convex hull or mesh. The primitive collision types are faster to use and more stable, but since this is a simple animation I’m guessing you won’t see a whole lot of difference.
One thing about rigid body simulations is that they’re very unstable at a small scale. I scaled everything up by 5 and that helped a lot. I also increased the steps per second to 350 which got rid of the wobble. Here’s the file:
http://pasteall.org/blend/index.php?id=52325
Hope that helps!