Hi!
I used a technique similar to that of Booleano (a nice rendering).

I respected the exact shape and dimensions of my clothespin (a cheap clothespin! The angles are sharp).
7 turns on the propeller. I made sure that the metal part does not bite into the wood (even in places where it would not be visible).
I think that in a self-study process it is important, in the virtual design of a real object (here the clothespin), to respect the exact shape and dimensions of the object that we reproduce (to tend towards this goal). This requires rigor, reflection and requirement. And therefore, allows you to gain skills and know-how. We are a winner!
The wood part is not a problem.
The spring is very formative: it must not bite into the wood (the clamp would not work. At the start I have 3 parts, the propeller and the two identical parts which turn at right angles with a "rounded" very tight. The difficulty is the connection of the 3 parts and the respect of the good position with the two wooden parts. I had to use "ReconstructCurve" and play on control points (displacement, to have the good curvature at tight angles).
In this particular case, your best bet is to take a wooden clothespin apart (cheap !!!) to observe and measure before you start.
Be careful, don't do this with a pretty piece of jewelry from your great-grandmother!
I am not a reference for practicing MoI3D, I only use it since V4.0 (so I am a beginner) but maybe my explanation will help other beginners.

What is sweet in French (apart from sweet)?

-Zooen