The present disclosure provides embodiments of a lapper assembly for use to overlap successive sheets of wood veneer or other materials along a conveyor. The lapper assembly may include a stop member configured to be rotatably mounted to a roller such that the stop member is pivotable around the rotational axis of the roller independently of the rotational angle of the roller. The lapper assembly may further include a lever arm coupled to one end of the stop member. An actuator may be pivotably coupled to the lever arm and the conveyor frame, and operated to pivot the stop member between a workpiece engaging position, in which the stop member extends into the path of workpiece flow, and a workpiece disengaging position below the path. Optionally, the lapper assembly roller and other rollers upstream/downstream may be operatively connected to a drive. Corresponding systems and methods are also disclosed herein.