Expert: Martin Meyer - 1/2/2010

Question
Thank you for your help. The clock is now running and chiming fine. To state my problem using the proper terms. The hammer tails were worn as the pinwheel was sliding off one side. This pinched the two together stopping the chime movement. I made a small brass washer and shimmed the pinion shaft (pinwheel) over to re-align it with the hammer tails.
Again...thank you for your help. I may call on you again.
Happy New Year 2010,
Dave  

Answer
Hi Dave,

First, I would mention that wear this severe on the hammer tails probably is a sign of severe wear elsewhere in the clock, particularly the bearings.

This is not a recommended repair. If you are absolutely certain that the hammer tails are contacting the same pinwheel pins as they did before, you may get away with it. If, however, the shims have shifted the hammer tails to different (incorrect) pins, you will never get the chime right.

Now, to address the chime synchronization problem. The large gear with the set screw is what is adjusted to synchronize the chime. First, loosen this screw. Turn the minute hand through the chiming cycle until the clock chimes the full 16-note sequence and strikes the hour. Then turn the minute hand until the first quarter has JUST been struck. Ensure that the chime gear train does not move at all further (I hold a finger lightly on the fly). Now, manually rotate the pinwheel slowly until the 4 (if Westminster) or 8 (if triple chime) hammers fall in sequence from the highest note to the lowest note (that is, from the shortest chime rod to the longest). Stop turning the pinwheel IMMEDIATELY when this strike occurs, and tighten the set screw on the large gear. The clock should chime correctly.

Fine adjustments are often necessary. If any chime sequence ends with one hammer partly raised, the set screw gear must be turned so that the pinwheel is a tiny bit less advanced. If, when warning occurs for the upcoming chime, a hammer is slightly raised by the warning movement, then the pinwheel must also be slightly less advanced. If the chiming sequence ends without hitting the final note, then the pinwheel must be slightly more advanced. These are VERY fine adjustments and require a good deal of patience.  http://www.clockmasteronline.com