An airplane prop is very complex
Granted, the props made here are duplicated from patterns, but some poor chap had to make the original. Apparently slight variations in the shape influence the performance quite a bit. The duplicator lathe is way cool in my opinion and I enjoyed the whole story behind the product and the company.
Anyone else see this video?
The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)