Take-Apart - The Balls and Chain

The Balls and Chain
The Balls and Chain - Drawing
Craftsman:John Berkeley
Material:Ebony, Piqua Amarello & Sterling Silver
Pieces:A few

The objective is to remove the chain. The balls at either end of the rod turn freely.
One of the balls will unscrew at the second grove allowing the chain to be slipped over the end. To unscrew it, you must hold the rod in one hand, pressing the small part of the ball against the rod so it will not turn. The drawing is from Professor Hoffmann's Puzzles Old & New, 1893.