Sorry everyone looks like I messed up and missed one of the pictures. I fixed it above please have a look for part 2.
John, i get an error message trying to view the attached new picture. Tells me to check back later.
Could the two parts be replaced with one? No splines no threads no keyways. It depends on what else these parts interface with I guess.
that would be a another solution if the design allows... perhaps Kelly can shed some light on this idea?