There is no source that I know of other then trying to find a parts clock as a donor. You can find bulk key/toilet chain in hardware stores but it will not work correctly . The bead pitch will be slightly different and that will cause inaccurate timekeeping. The last known source was a guy in Singapore that sold Golden Suspense motors and chain on Ebay. Its a shame that so many of these clocks are missing something as simple as chain. They are really cool clocks.