Expert: Martin Meyer - 11/16/2009

Question
Have just received a Warmink moon phase clock via Ebay, the clock works OK but the moon dial does not seem to move,can it be set fairly easily ?

Answer
Hi Alan,

You will have to access the area between the moon dial, which is mounted on the main dial, and the front movement main plate. This may require removing the movement from the clock. Additionally, there are several methods of moon dial operation, so I will answer assuming that you have the most common type, which is probably used on 90% of clocks.

The moon dial is moved forward one click per day (on most modern clocks) by a series of gears mounted on the back of the main dial. The gear closest to the moon dial has pin on it which catches a tooth on the saw-toothed circumference of the moon dial and moves the moon dial forward one click each day. This small pin often breaks off. If you rotate the hands through a 24-hour cycle while you watch the moon dial, you should see this pin move the moon dial at some point. This can happen at any hour, it usually does not just click forward at midnight. If the pin is broken off, you will need to replace it or have it replaced by a professional clock repairer.

Second, the moon dial may be crooked, that is, out of parallel with the main dial, and the pin may miss the tooth. You can usually gently bend the moon dial back into position so that the pin makes contact with the saw tooth.

Finally, there is also a large flat spring, usually brass, with a detent on it which lightly engages a saw tooth of the moon dial. The function of this is just to keep the moon dial in position. Sometimes this spring slips off the saw toothed edge of the moon dial, and jams between the moon dial and the main dial. If this is the case, you can gently bend this spring back into position, so it rests right on the saw toothed dial edge.  http://www.clockmasteronline.com