Abstract: A conveyor mechanism feeds stock material into a material working station. The conveyor mechanism includes a frame, a feed roll, a pinch roll, a pinch roll lift mechanism, and a height monitoring device. The feed roll has a feed roll axis, the feed roll axis being rotatably fixed relative to the frame. The pinch roll opposes the feed roll and is selectively moveable relative thereto. The pinch roll has a roll lift position relative to the feed roll. The pinch roll lift mechanism is configured for selectively controlling the roll lift position of the pinch roll. The height monitoring device is configured for monitoring the roll lift position and measuring an actual roll lift height of the pinch roll. The height monitoring device is operatively coupled with the pinch roll lift mechanism in order to permit the actual roll lift height to be used by the pinch roll lift mechanism in selectively controlling the roll lift position.