Skillful planning and the reliance on frequent face-to-face interaction is often emphasized as preconditions for successful project work in literature on project management and product development. Our case study observations of a project involving the development of a new stacker, however, contrast with such a view. Here, most project work was carried out individually and as a matter of routine, complemented by interactive instances, such as project meetings and ad hoc problem solving interaction. Moreover, instead of a shared project goal or a shared knowledge base, the material stacker stood out as an artifact of great significance in achieving activity and knowledge coordination. Inspired by literature on sense-making, we propose a simplified model of the individual-collective dynamic in such contexts, and differentiate between processes of interacting and interrelating. Finally we discuss its coordination properties as a matter of cognitive feasibility and economizing on cost.