Tuesday, January 12, 2010

The Rack Must Fall!

How does a cuckoo know how many times to call? Why is my clock only calling once when the hands say 3:00?

These are great questions, and the ingenious works of a mechanical clock can do it, but a few things have to be in proper adjustment. Here are some things to watch out for to keep your clock working, and keep your cuckoo calling the right number.

First, check the hands.

We already have an article about the proper alignment of a cuckoo clocks hands.

Second, check the rack.

Here you can see a picture of one of our cuckoo clocks with the dial removed. Circled you see a black, sickle-shaped part that we call the "rack." This part has a certain number of teeth on it that are counted by the brass pin to the right of the part.

Sometimes, through excessive handing upside down, this rack can get stuck in a position that is too high for the pin to count its teeth. In the picture below, you are looking at the clock mechanism from the back. You can see the top part of the rack as a black hump, sticking out of the top of the mechanism.

In the picture above, the rack is in a position too high for its teeth to be counted. With the rack in this position, the clock will only cuckoo once every hour, no matter the time.

This can happen due to excessive handing upside down, or sometimes during shipping.

You can see in this picture where the rack is lower and in the correct position, as viewed from the back:

The good news is that the clock can be fixed with a simple adjustment so that the clock will cuckoo the correct amount of times every hour. Simply take a long object, like a pencil, and push down on the hump of the top of the rack so that it falls below the top of the brass mechanism. This will allow the rack to fall so that its teeth can be counted.

Push down in the direction of the arrow.

After you have completed this procedure, your clock should begin counting more than once call every hour. You may have to readjust your hands to match up with the mechanism after performing this adjustment. Refer to this article again to make sure that the hands are set correctly.


  1. Anonymous11:02 PM

    thanks for the great instructions

  2. Anonymous1:48 PM

    I have been looking for an answer to one cuckoo no matter what hour. Thanks for the indepth directions. My clock is working perfectly now!

  3. Anonymous10:24 PM

    My mom gave us a cuckoo clock, but it was only calling once every hour. It's a small clock, so I figured this was all it did. Until reading this! I opened the back, saw something that looked familiar to your pictures. I pushed it down, and like magic, it works!!! AMazing! Thank you!

  4. Mine was working fine, then while never moving it, It started single calling . I read this and found my "rack" loose, not stuck. How do you remove the face? Mine is very old 40+ years