Expert: John Newman - 2/16/2011

Question
Hello Mr. Newman

My wife and I just purchased an Emperor floor model clock (Grandfather) which was not working and when I opened the back I found that the pendulum spring was broken.  I had a sample and purchased a new one in Frankenmuth, Mi at the clock shop.  I replaced it and the clock is now working, and keeping great time, with the exception of the moon dial, which does not turn. I see that it has a gear on the back which we moved around to coincide with the time of day, but it still does not work. Can you offer and information about this?  The clock has a Jauch 77 works.

Thank you,

Wallace

Answer
Wallace, when you say that you moved the gear on the back, I think you might be referring to the actual moon dial which looks like a circular saw blade.  The Jauch 77 does not drive the moon dial with a gear but a cam lever on the hour tube.  The hour tube is like a shaft to which the hour hand attaches.  The cam lever contacts a lift lever on the moon dial which enters a tooth on the moon dial and moves it one notch, twice a day.  It does not have anything to so with the time of day.  If the cam lever is not engaging the lift lever, or the lift lever is not entering the tooth at the correct place, or if the moon dial detent spring is not in place, the moon dial will not move.  Most of this cannot be seen while the movement and dial are installed in the clock.  To check it out and fix it usually requires the movement and dial to be removed from the case by an experienced clockmaker or someone that has built one of these clocks.  

Also, I am not sure what you mean moving the gear to coincide with the time of day.  The moon dial is set according to the moon phase found in various places like the Weather Channel, the weather page of your newspaper or you can look up moon phases on the Internet.  The easiest way to set it up is to wait until a full moon.  On the day of a full moon, turn the moon dial until it shows a full moon (if the dial will not turn it is probably because the clocks is in he midst of advancing it.  Wait a couple of hours and then you should be able to turn it.  From then on the moon phases will keep up.  You can also set it on the day of the new moon by turning the moon dial until no moon show.  One further point and that is that the numbers above the moon dial have nothing to do with the day of the month.  They show the days of the phase of the moon which would be 29-1/2 days, as shown on the last number.   I hope this helps a little.


John Newman
THE VILLAGE CLOCKSMITH
Old Prattvillage
Prattville, Alabama