Nautilus by Bernard V (Click to enlarge)
Wow! Bernard, you are truly an artist. Your Nautilus is beautiful. I love the sun and moon motif you used on your hands as counterweights. Beautifully done. You really did the Nautilus plan proud.
The following exchange from an email correspondence after Bernard sent me this picture of his Nautilus. My comments and answers to his questions are in red print.
Bernard writes: "I have a question concerning fine adjustments on Nautilus' speed. My understanding is that it has a compound pendulum; so if it runs fast one raises the bottom bob and if it runs slow one lowers the bottom bob ( reverse of a simple pendulum)... Am I right ?" What you describe is the correct treatment of a compound pendulum bob, however the Nautilus' pendulum is not a compound. It looks like a compound, but isn't. The upper bob is there only for artistic purposes, which is why I made it small and light.
Nautilus is completely designed using the Golden Mean. Each of her pieces relates to the other pieces by a ratio of 1 : 1.618 or some multiple of that. The upper bob, as well as the other components and 'hangy' pieces are all related by the Golden Mean, even though some of the pieces are only artistic additions and thus superfulous mechanically. "Also, does one also make adjustments to the top bob ( the smaller curved piece at the top of the pendulum which has no lead ball added) ?" No adjustment to the upper bob is needed.
"I am attaching a picture of my Nautilus taken during testing period; Your can use it as you wish on flicker or your blog ! As you can see, I did some very small modifications; design my own minute and hour hands," Your hands are art by themselves! "use some old market weights I had (3.5 lbs on main weight as prescribed and a tiny 5 oz one as counter-weight), and I had that little bell I wanted to use so I re-figured the action of the pivot arm and the counter-weighing of it to make it work ( done thru testing, took a whole day !!!)" I always enjoy hearing stories about how other woodworkers get to experience the joys of spending all day on a single re-modification. It sort of puts everything into perspecive. Designing is not as simple as it may appear, but the joy at the end when the mechanism is working is unlike anything else, and you've done an amazing job creating your Nautilus. Congratulations!
"Thank you for your great plans!" And thank you for creating such a beautiful mechanism.