Ah nice one Brian,
Do you use a non-pushbutton version to drill through? And you must have to be very precise with your drilling as these have quite narrow shafts? Any chance of a tutorial?
EDIT: Oh I see, I should have looked more closely. You are using two encoders side by side with a gearing arrangement. Interesting idea. I have seen somewhere someone using the drill through method with one connected behind the other but at $10 each, you may as well buy the prefab ones from the Brazil sim dealer I linked to above.
Ken.