This paper proposes two contrasting metaphors as models for the management and knowledge-building process in complex engineering projects. It describes the roots of interpretive models of social action, then elaborates on two alternatives: a Taylorist, control-oriented funnel model and a contrasting and more chaotic fermentation vat model with flexible learning capabilities. These cultural models are illustrated through an ethnographic field study of a manufacturing automation project for computer assembly at Apple Computer, Inc. Apple's engagement with a Japanese mechanical contractor to design and build the assembly line provides contrasting examples of project management cultures.