You should be used dryed/cured wood stock. Using fallen branches will likely produce pieces that crack, shrink or distort in only a matter of a few days.
Is there a way to fasten the stick to those clamps to make it more steady when you drill? I want to do the exact same thing.. trying to understand if I’m buying the right drilling machine
Don't be a hole Dave. I don't see any videos on your channel smart guy. Ever heard about keeping your mouth shut if you don't have anything nice to say?