Sometimes Reality Doesn't Cooperate: The Monotonous Pi Clock

Not all clock plans make it for sale on my website.  This is the story of Pi.

Above:  Monotonous Pi 3D Renderings made from my dxfs

by my friend, Oleg in Russia

Below:  Pi, actually built by me, in motion below:

The Monotonous Pi is a kinetic sculpture posing as a clock. It has all the parts of both a clock and a kinetic sculpture. That huge circular pendulum has a very slow forward and back oscillation of approximately 38 beats a minute. Monotonous Pi has its roots in the Medieval 1300’s when the verge and foliot clocks were the techie’s state of the art timepieces. They weren’t very accurate. They could be off twenty minutes a day…plus or minus. That’s a pretty huge possible error spread, and that error rate in timekeeping, with only slight improvements, continued until the late 1600’s when the seconds pendulum was introduced by Galileo and others - like Christiaan Huygens (who, in my opinion, never gets enough credit). But not all verge and folio clocks had such problems with accuracy. Christiaan Huygens (1629-1695) had a suggestion that I’ve incorporated into all of my verge and folio clock designs (except Monotonous Pi), and they are actually quite accurate timekeepers. Huygens recommended a return spring on the verge to increase the clock’s accuracy. My designs, other than Pi, have just such a return spring which is created by the spread of the cord from which the verge and foliot is suspended. Most verge and foliots in those early days were suspended by a single strand of silk. By changing over to a loop of cord we can add that return spring advantage to our verge and foliot clocks that Huygens suggested, and this simple improvement increases their accuracy dramatically. You can see that loop of cord suspending the verge and foliot in my Medieval Rack, Holologium, and Wee Willie designs. But…Monotonous Pi is not one with a looped suspension cord or return spring, so its accuracy is very similar to the workings of those early Medieval clocks - which is not very good…but sometimes it’s right! However, on the other hand, as a kinetic sculpture the Monotonous Pi is excellent! Pi is a visual delight. It is lovely to watch Pi’s slow oscillating movement forward and back. And it does try so hard to keep good time, even though it’s not very good at it. Still…Monotonous Pi is one of my favorite sculptures. Pi is truly a delight to watch.

Aloha, Clayton

Verge and Foliot Escapement Adjustment on Horologium

Horologium by Joe Coser

Joe Coser writes:

 

Good morning Clayton,

Attached is a picture of the Horologium I just finished. Thank you for the excellent plans and directions.  I am working on the time it runs fast. I have reduced the weight to 5#--I think I will try reducing it more before making the alternate wheel.

Thanks.

 

Very nice work, Joe. Your Horologium is a beauty. Each part of your clock is so crisp, and clean, and well made. Your excellent craftsmanship shows throughout your build.

 

You are correct about decreasing the drive weight if your Horologium is running too fast. Many of my clocks have escapements that are not very sensitive to how much drive weight is applied and a little excess drive weight is not a problem. That is not the case with the verge and foliot escapement of the Horologium. V&F escapements are very sensitive to changes in drive weight, and as an aside that is why, instead of using a standard clock mainspring, I went with a constant force spring in the Wee Willie. A verge and foliot escapement requires that the drive force applied to it be constant.

 

As you probably read in the instructions for the Horologium, there are three ways to change the speed at which this type of escapement runs; 1) vary the drive weight, 2) open or close the "wings" of the foliot, or 3) change the number of pins on the escape wheel. Actually, there is also a fourth method and that is to add more weight further out on the pendulum's shaft. In other words make a wider or heavier foliot. That could be by adding additional weight in the wings themselves or a separate foliot addition down by the sphere you have put on the bottom of your pendulum's shaft (actually, adding weight further out anywhere along the shaft would work.). You can see how John Hilgenberg did just that by checking out the picture of his Horologium in my Flickr' link.

 

Thanks for sending the picture so we could all see the great work you put into building your Horologium.

 

Enjoy.

 

Aloha. Clayton