28-03-2025, 10:10 AM
(20-06-2023, 03:02 PM)Dave Wrote: A critical part of the Sextus are its pendula, as they are at the end of a long gear train they receive the least amount of drive force and if they are not swinging as efficiently as they should then it will prevent your clock from running.
A major source of friction can be the rear bearing on the pendulum arbor, a simple way of reducing this is to shorten the arbor and chamfer the end so that it just about sits in the bearing but can easily move around.
The main weight of the pendulum is supported by the front bearing and the rear bearing is merely to keep the arbor in position.
You can test this by simply comparing the swing times of the pendulum in its original position and when you have moved the pendulum forward by
loosening the ring stops so that the arbor at rear just about sits in the bearing, you should notice some improvements.
The hour and minute hands on my Sextus hand did not move anymore. It appeared there was some torsion in the frame. Looking from the side it looked as if the front part of the frame was a little lower than the back part. I could also move the front part a little bit up and down manually. I took the clock apart and aligned the both frame parts and really tightened the screws which connect the frame parts. Problem solved. Clock is running again for months now. Cause??? No idea, but I guess combination of temperature, humidity, the wood setting itself, ..., ...