Unable to combine two bodies

[Anonymous]

I'm having issues combining two bodies together.  It likely stems from the fact that the bodies where imported from .STL files and then converted to BREPs.   Two of the bodies combined very well, but the third did not.

I've attached the .f3d file for someone to have a look at. Would love to know how I can fix this so I can join the remaining two bodies.  
I can't see anything blatantly wrong with either body... likely something extremely minor (I hope).

I'm also hoping to smooth out the surface if at all possible, but hope to get the combine done first.

[JDMather]

Given that the geometry is planar triangular facets and relatively simple - I would simply use it as reference in recreating from scratch.

Looks like about 30 minutes of work.

[Anonymous]

Thanks JDMather.

I agree that recreating from scratch is likely the best option, however, this is beyond my current abilities in Fusion360.

I did try recreating and using projections to get the grooves on the hemisphere, but the grooves did not align correctly.  Spent a couple of days trying this.

If you have some links to tutorials on how I could accomplish this, would greatly appreciate it.