The president of our woodturning club is a very clever guy and good turner. He is former rocket engineer and has unique visual abilities that translate into work that comes off his lathe.
This item was at our last show and tell. I haven't a clue how he did it. Many of us examined the box closely, there are no glued up bandsaw joints anywhere. He turned it all. The ball is as perfectly round as the eye can detect. Unfortunately, he did not do a series of in progress pictures.