Setting an anniversary clock in beat
Setting the beat accurately on a 400-day clock is not always easy. I have found the following dynamic method to be quick and accurate.
After setting the beat using the conventional static method I have found that when applying the dynamic method the clock is not properly in beat which can result in stoppage or limited running duration.
Setting up using the dynamic method requires position markers and for this purpose I use four upturned drawing pins. Firstly, set up using the static method, ie with the pendulum at rest, rotate the pendulum by hand and note the distance travelled before escapement happens. Repeat, rotating the pendulum in the opposite direction and adjust the saddle to give equal distance of travel in both directions. When this has been done and the clock has been running for 10 minutes or so, the four upturned drawing pins are placed on the base plate as shown in the photograph. The two inner pins B and C are positioned to mark the point at which escapement happens and can be positioned next to one of the pendulum arms. The two outer pins A and D mark the position of maximum pendulum rotation. The inner pins need to be positioned accurately. To achieve this I listen to when escapement happens and visually note the position of the pins. The pins are then moved to mark the precise position where escapement occurs. This may mean moving the pins a few times before the exact position can be found. At this stage, it can be seen that the distance between pins A and B is not the same as C and D, indicating the clock is not properly in beat. Adjustments can now be made to the saddle whilst the clock is running. A small rotational adjustment to the saddle will make a significant difference, thus, only minute adjustment is needed. When viewing from above, to increase the distance AB turn saddle clockwise or anticlockwise to increase CD. After making an adjustment the pins will need repositioning and it may be necessary to make another adjustment to achieve equal distance of AB and CD. The pins can be left on the base plate for some time and it is reassuring that after several weeks a quick visual check will reveal the clock’s exact performance
The photograph shows the pendulum arm adjacent to pin B when escapement happens with the pendulum rotating clockwise. Pin A is the maximum the pendulum travels in the clockwise direction.
Peter Simpkins, UK
