Retrograde

“2:27:43”

Unlike a classical retrograde display, I wanted hours to be primary rather than minutes. (‘Makes more sense to me.) I designed the hour hand to mimic the sun (or the moon) - “over here at sunrise”, “straight up at noon”, “over here in the afternoon”, and “down here in the evening”. At 7:00, the hand flips back over and starts again. The minute hand, lower left, is “straight up at zero”, “half way at the half-hour”, etc. Seconds just go “around and around”.

This picture shows 3:44:12.

This began as a birthday present - a beautiful piece of padauk wood. (friends know what pleases me!)

In this close up, you can see the minute cam on the central arbor, with its follower / rack extending down into the minute display. The hour cam is in the upper right (just below the “2”).

You can also see (just left of the “55” in the minute display) the winding ratchet for the Huygens “Endless Chain” drive system.

Being an engineer, I’ve always subscribed to “form follows function”. That is, design something to work optimally, and then make that look good.

But with this clock, I knew exactly what I wanted it to look like. It’s the first time I’ve designed and built the dial before I finished designing the machinery. And I wanted a half-seconds pendulum.

To make a long story short, I boxed myself in to a 2-1/4 inch diameter 60-tooth escape.

I chose a Recoil, so it would be forgiving, and with only 1-1/2 degrees pendulum swing, so it would have enough “drop” and the tiny teeth would have some strength.

To my amazement, it works beautifully! …And very efficiently: This clock runs 30 hours with only a 12-ounce weight at 42” fall.

(The only problem is that with that tiny pendulum swing, it’s very sensitive to being straight on the wall.) “2:27:43” the Retrograde

I have a beautiful old Art Deco retrograde display watch, and I’ve always been fascinated with the mechanism - I had to build one.