My 25-year-old cuckoo clock hung on the dining room wall silent for over two years. Finally, this month, I decided to see if I could repair the clock to produce the comforting, hourly cuckoo whistle that previously filled our home day and night.

Eager to attempt the repair and learn how the cuckoo whistle is accomplished, I studied a library book called “Handbook of Watch and Clock Repair,” by H. G. Harris. During a visit to a local watch and jewelry repair shop to pick up a resized ring, I inquired about what might be wrong with my clock, which required extra weight on the timing mechanism to keep time and cuckoo. The off-hand diagnosis was, “cleaning and oiling” is necessary but an effort best avoided as a first-time endeavor. Stubbornly, with confidence and knowledge gained watching a 45-minute YouTube video about cuckoo clock repair, I ignored the advice then set out dismantling the clock by removing the internal mechanism called the “movement.” My efforts quickly became frustrating, depressing, embarrassing and probably costly now as well, since I damaged the cuckoo whistle bellows.

By examining the cuckoo clock movement, I hoped to understand the mechanism so that I could explain the workings to interested readers. I have to confess that even after holding the movement in my hands and studying diagrams in the repair handbook, I remain baffled and mentally challenged by the internal workings creating the sequence of cuckoo whistles corresponding to the hour. The situation became worse when I tore the bellows on top of one of the two whistles that generate the “cuc” and “koo” sounds. Power to move the clock hands and generate the cuckoo whistle is provided by two weights that hang outside the clock and require manually pulling them up every three days. The weight used to move the minute and hour hands spins a wheel edged with teeth which strikes a lever attached to a pendulum. The pendulum is pushed one way then on its return is pushed again day after day, preventing the natural tendency for the pendulum to slow and eventually stop. With each swing of the pendulum, the minute hand is moved clockwise ever so slightly. By lowering the weight on the pendulum, the swing becomes slower, or by raising the weight, the swing becomes faster so the time-keeping accuracy can be manually adjusted.

The cuckoo clock, just like any striking clock, utilizes an offset oval or cam on a shaft with 12 notches. Each notch corresponds to an hour of the day. As the top of an hour approaches, the gear mechanism and cam make the cuckoo whistle at the hour-specified times. Upon removing the rear cover of the clock, two narrow, vertical wooden boxes similar to organ pipes became visible on each side of the movement or gear mechanism. On top of the boxes, tiny bellows made of thin “kid” leather open to receive air then close to push air into the vertical boxes and out a narrow hole to create the whistle “cuc” from one box and “koo” from the second box – similar to the mechanism of a flute. As the cuckoo bird is pushed out of the door on the clock, the tail rides over a wire, tipping the cuckoo’s head down. Then, the door is closed by a wire attached to the cuckoo as it retreats. I must say, it’s quite a remarkable invention.

Interestingly, the bellows which draw in air and force air out through the wooden pipes to create the cuckoo whistle are made of thin animal skin. This material tolerates motion of filling and collapsing hour after hour, day after day, and year after year without cracking, splitting or disintegrating as rubber or plastic likely would.

The moral of my story likely has become evident. A lesson I have learned in life but occasionally forget is to let the experts handle special disruptions in my life, be they equipment repair like my lawnmower, automobile repair or health care. In the long run, time, money and peace of mind will be preserved.