How to Adjust the Pendulum on a Cuckoo Clock to Keep Perfect Time

Set up the clock correctly according to directions and hang it level on the wall so that the pendulum has enough room to swing freely. Slide the carved balance piece onto the pendulum shaft if it is not already in place. Place it about two-thirds of the way from the clock. Pull the chains of the cuckoo clock so that the clock weights are touching the clock housing. Gently move the hands of the clock to the correct time according to a clock that you know to be accurate, such as a digital clock. Start the cuckoo clock by giving the pendulum a gentle swing.

Wait two or three hours and keep an eye on the cuckoo clock. Compare its time to a clock you know to be accurate, such as a digital clock. Note whether the cuckoo clock runs faster or slower than the accurate clock.

Unhook the pendulum from the clock and move the carved balance piece of the cuckoo clock up the shaft of the pendulum if the clock runs too slowly. Moving the balance piece toward the clock housing causes the pendulum to swing faster, speeding up the clock. Replace the pendulum and wait another two or three hours, comparing the cuckoo clock to the accurate clock to see if you have adjusted the balance piece enough.

Take off the pendulum shaft and move the balance piece down the shaft of the pendulum if the cuckoo clock runs too fast. The lower the balance piece, the slower the pendulum will swing and the slower the clock will run. Replace the pendulum and wait another couple of hours to see if the adjustment was successful.

Repeat moving the pendulum balance piece as needed until you get the cuckoo clock to keep perfect time. This may take all day for a new clock. Have patience and handle the clock gently when removing and replacing the pendulum.