Knocking the bobbins is how lace-makers refer to “lacing”. It is an act that, at first sight, does not present any specific technical function, but which, on closer inspection, reveals itself as a fundamental elementary act for elaborating a good lace, since it ensures the firmness of the weave. Through an analysis of the different meanings of this category, the article discusses the relationship between, on the one hand, gesture and rhythm, and, on the other, effects and resulting forms. Each of the senses of knocking the bobbins analysed here are, in turn, tied to different levels of action, since all involve gestures, rhythms, effects and specific forms.