This post is really just for those interested in what “a worn spring” means.
When a spring is wound it is peeled from the outer or the barrel onto the winding spiggot. Over time the spring loses its elasticity and starts to take on the shape of the spiggot as opposed to the outer barrel. This is a complicated clock repair because it takes some time to dissassemble the movement, remove the barrel and then extract the spring. A new spring must then be wound to a lower diameter, inserted into the barrel and then released to a snug fit inside.
The picture below shows the extracted spring and the new spring. You can seet the difference!.