I am trying to animate a button that is on a non-global angle. I am using a custom transform orientation to rotate the object in the manor that i want it. I simply have a keyframe with it closed at the start and a keyframe with it open at the end however it is taking a weird path.
This is what is happening:
This is what i want to happen:
Many Thanks in advance.
Dan 
Wow - I have also been working on technical animations on the interior of trains!
Anyhow, the key is to parent the flip-button thing* to something at the rest angle, then when you animate it, it should move fine. You could create an empty, and angle that to the desk, then parent the flip-button to that, then when you animate, it should animate fine. It doesn’t have to be an empty - it could be that panel of buttons.
*… though I’ve obviously not learned the correct name of those things.
Brilliant! This fixed the problem and it is animating fine now. Thanks a bunch!