I think you need to set the collision radius of your meshes.
It looks like you're scaling your meshes very small. I can't tell for sure as your meshes might be huge to begin with. The default collision radius is 1 (I think) which will be too big if you've scaled your meshes right down.
It looks like you're scaling your meshes very small. I can't tell for sure as your meshes might be huge to begin with. The default collision radius is 1 (I think) which will be too big if you've scaled your meshes right down.