Presidents Message,
Next meeting is November 12, 2023
We had our location temporarily moved to the larger hall just behind and to the south of our normal location and it seemed to work out well. This is likely a one time move due to some conflicts with the normal location from the American Legion perspective.
We will continue to need some help setting up and taking down. So arrive at 9:00 and help setup and stay after the educational talk to help return the room in the condition we found it in.
Opens at 9:00 for setup and mart. Mike Dempsey and I will be presenting a Seminar on Tool Sharpening with Focus on Jewelers’ Lathe beginning at 10:00 during the mart. Educational talk by Tony Zimmer on “Finding the Right Screwdriver” at 11:00. Cleanup at 12:00.
We also need a new secretary. The main job is just to put this newsletter together. Please offer to help so no one is overburdened, only takes around an hour per meeting.
We have had some requests to add some hands-on teaching in basic clock repair. We are starting with Tool Sharpening in November during the mart. At the close of this first one we will discuss future subjects. Please email me any ideas you have for future seminars.
Congreve Clocks
Craig White gave a talk on the history of the Congreve rolling ball clock. Mike Demsey and Mike Figueira brought some of their Congreve rolling ball clocks to show as examples. Both Mikes talked about their clocks. Mike Figueira’s clock was even working during the Mart and Talk. Thanks for bringing your examples.
The rolling ball clocks are mesmerizing to watch the ball going back and forth in its zig-zag pattern until the ball triggers the table to tilt in the other direction. Then the ball moves in the opposite direction. The clocks are not good time keepers but are fun to watch.
Sir William Congreve was able to obtain a patent for his clock design in 1808 but he was not a clockmaker. Rather, Congreve fancied himself as an inventor and his designs included counterfeit-proof paper, pneumatic canal locks, and even a perpetual motion machine. He is probably most famous for his development of the Congreve rocket, a weapon which was successfully used at the battle of Leipzig (Germany) in the Napoleonic wars and less successfully at the siege of Baltimore during the war of 1812. These were the rockets alluded to in the American National Anthem.
Why are they poor time keepers? The answer lies partly in the way they operate. The clocks are intriguing to watch as a small ball rolls down a zig-zag path on the pivoted table. When the ball reaches the end of the path, the table tilts and the ball rolls back the other way. The tilting of the table is the oscillation that the clock depends on.
The single largest timekeeping problem of these clocks is that the oscillator has no natural period of vibration. The clock is completely dependent on the time taken between the two trigger levers being moved by the ball. This is, of course, dependent on the time taken for the ball to move down the zig-zag slope. Any perturbation of the movement of the ball will result in an inaccuracy in timekeeping. It is necessary that the surface of the ball and the groove in the table be kept free of dirt, particularly oil or grease which would increase the friction between the surfaces and slow the ball’s descent. This is not the only cause of error. To be truly accurate, the ball must take an equal time to complete its movement in both directions on each and every cycle. Reproducibility is paramount. A major problem exists in that as the table is lifted the ball begins its descent. If there is a lack of uniform motion in the gear train of the movement through friction or other means, then the acceleration given to the ball will not be uniform and its rate of travel will be different on each pass. Congreve was unaware of the importance of this dependency of his clock as opposed to a clock with a pendulum or balance wheel that is oscillating with a natural frequency.
Congreve was also unaware that when the detent wheel is abruptly stopped by the pin hitting the end of the detent lever there is kinetic energy which must be converted. In John Wilding’s clock design, he places a fly on the detent wheel arbor in an attempt to absorb some of this energy. Nonetheless, on close examination of the table’s movement in slow motion, the energy in the table as it comes to rest in its new position causes the table as it to “flutter”. This fluttering will significantly affect the movement of the ball as it starts its downward journey.
Mike Dempsey and Craig White will each be making a Congreve Rolling Ball Clock to John Wildings design. Further talks at the chapter meets will be given showing our progress.
Future educational talks planned:
November 12 – Tony Zimmer will give a talk and demonstration entitled “Finding the Right Screwdriver”
February 4 – Harry Schultz will be giving a talk on Making a Calendar Wheel
March 10 – Danno will make a Presentation on Renaissance Clocks
We still need volunteers for talks and/or demonstration for 2024. Please contact Harry Schulz or myself with ideas or suggestions.
Free tables!! A free silent auction table will also be available. We had some more clocks donated which the chapter will be selling at the silent auction table.
Hope to see you all there.
Thanks,
Craig
