A slip mechanism in the gear train of a clock comprises a gear wheel and an associated pinion coaxial with the gear. The gear wheel and pinion have interengaging surfaces for centering and rotatively guiding them relative to one another. A circle of resilient fingers on one of the gear wheel and pinions resiliently, frictionally and radially engage an annular friction surface of the other to provide a frictional coupling between them. Moreover hooks on the fingers retain the gear wheel and pinion in assembled relation to one another. In one embodiment the resilient fingers are integral with the pinion and are received in a concentric opening in the gear wheel of lesser diameter than a circle defined by the fingers in relaxed conditions. In another embodiment the resilient fingers are integral with the gear wheel and engage the outside of a concentric flange on the pinion of larger diameter than a circle defined by the fingers in relaxed condition. The pinion and gear can readily be formed of plastic material thus providing an inexpensive slip mechanism which can be easily assembled.