Hey guys! Would morph targets be a good idea to create some models that have rotating parts which constantly rotate?
No.
Unless you have HUGE number of morph targets, rotating parts made using morphs will be turning inside out.
Could you explain to me how would meshes like that be made?
the part of the model you want to rotate make it an actor BP then in the EventGraph drag off the event tick and Add Relative Rotation to the Mesh then place a number in the x or y depend on how you want it to rotate 
Oh, nice. Thanks!