That’s quite a gearbox face plate you have there.
http://instantrimshot.com/classic/?sound=rimshot
I like the slotted CIM mounts. It’s a neat way to change gearbox speed after you fabricate.
Is the bottom slot just to make the whole thing look like a smiley face, or is it functional?
Yes, it gives it good juju. But actually, everything on it except for the mouth is functional.