Cuckoo clocks are popular mechanical clocks. A cuckoo emerges from a small door to report the time. The time itself is regulated by the swinging of a pendulum, while a system of weights supplies power to the internal gears. The weights hang down from chains that pass through wheels that are located inside the clock. These wheels turn other wheels, ultimately moving the hands of the clock, and operating the cuckoo and any other figures on the clock case. On occasion, a cuckoo clock chain breaks, and must be replaced.
Open the back of the clock to find the broken cuckoo clock chain. Remove the broken parts by gently lifting the chain off the sprocket wheel. The sprocket wheel is the toothed wheel over which the chain passes. Pull the broken parts of the chain down through the holes at the bottom of the cuckoo clock.
Purchase a replacement chain for the cuckoo clock. Cuckoo clocks contain either one-day or eight-day movements. Each requires a slightly different kind of chain. Both chains are 6 feet long. One-day movements employ a chain with approximately 48 links to each foot, while eight-day movements use a chain that has about 60 links to each foot. If the cuckoo clock must be wound daily, it has a one-day movement; if it needs to be wound once every eight days, it has an eight-day movement. Buy cuckoo clock chains from cuckoo clock parts suppliers, such as the Frankenmuth Clock Company, and Black Forest Imports. (See Resource list.)
Install the new cuckoo clock chain by threading it up through the hole beneath the sprocket wheel. Feed the chain over the teeth of the sprocket wheel, and back down through the next hole in the base of the cuckoo clock case.
Turn the clock upside down. Grab hold of the 2 ends of the new cuckoo clock chain, and pull up toward yourself. Pull gently, but firmly. It may take a few tries, but the chain should slip snugly into place around the teeth of the sprocket wheel. Turn the clock right-side up.
Test to see if the new cuckoo clock chain is correctly engaged by pulling down on of the chains. The chain should move freely, and make a regular clicking sound.