Different situation follows when two surfaces (c-housing.stl and c-interface.stl) have their common intersection to be caught. Utility surfaceBooleanFeatures can extract the intersection between two .stl surfaces.
surfaceBooleanFeatures intersection constant/triSurface/c-housing.stl
We can remove all the unnecessary files then.
rm -rf *.obj
Figure: Edges, compressor wheel and interface.