Variability in the escape wheel of a Self Winding model 41

The graph below shows the performance of a Self Winding model 41 clock with mercury pendulum. This escape wheel is somewhat eccentric and shows large variations between each tooth. The variability of rate with each rotation of this escape wheel is 1.4 hours per day. You can see the repeating pattern of tooth spacing in this graph, which shows about five complete rotations.

Self Winding