Expert: Martin Meyer - 3/9/2008

Question
Hi,

I have a Waltham wall clock that is about 13 years old. It is a 31 day pendulum clock with 2 weights.  Tonight when I started winding the chime, it felt like a huge spring had suddenly "sprung".  The sound was deafening, and it even knocked the winding key out of my hand.  Now the chime does not work, and it cannot be wound - it merely turns and makes a slight grinding noise.  Everything else seems to be working fine.  What in the world happened?  Is this something I can fix?  Thanks so much for your help.

Answer
Hi Angela,
    The mainspring on your clock broke when you were winding it. This was not caused by anything that you did, it just happened. 31-Day mainsprings are huge, 196" long, and deliver dangerous power release when they break.
    The only reasonable remedy for this is to replace the entire movement. Replacing the mainspring only would require disassembling and overhauling the entire movement (in most cases), and would cost more than a new movement.
    You can try obtaining a replacement movement from a clock supply house and installing it yourself, or you can have a clock repairer do it. The critical factors in obtaining a replacement movement are 1) a movement that takes the same pendulum length as you now have, and 2) a movement with the winding shafts and center shaft in the same relative postions so that they will line up with the holes in your original dial.