Many researchers are interested in developing robust, skill-achieving robot programs. We propose the development of asensorimotor primitive layer which bridges the gap between the robot/sensor system and a class of tasks by providing useful encapsulations of sensing and action. Skills can then be constructed from this library of sensor-driven primitives. This reflects a move away from the separation of sensing and action in robot programming of task strategies towards the integration of sensing and action in a domain-general way for broad classes of tasks. For the domain of rigid-body assembly, we are exploiting the motion constraints which define assembly to develop force sensor-driven primitives. We report on the experimental results of a D-connector insertion skill implemented using several force-driven primitives.