Thanks to the folks here, I have been working to clean up this part. I think all the tangent rails and triangular surfaces have been eliminated at this point. I still have a some work to go. However, I tried add these two closed surfaces together and I get a big fail. I did an intersection on them and the results are closed paths.
I can join the two using splits. I was just wondering for educational purposes why this does not form a boolean union.
Problem Add 2.3dm (970.1 KB)