Oops! The cap was not quite aligned to the axis of the lathe and when I was sanding, the brass tube made an unwanted appearance.
However, I think the concept is good, but the execution was flawed. I think I know how to avoid this on the next attempt.
My wife says, "Gestalt calls for the presence of a clip." On this one I may attach a piece of maple to look like a clip and to cover the brass. That will also stop it from rolling around on the desk. On another, I will try to use a clip from a kit, and attach it to the cap with a tenoned tassie using a contrasting wood. Or maybe the same wood. The tenon will require the cap to be a bit longer.