The Thayer all-stainless steel MWF-SGSP-OS sanitary, open-construction weigh belt feeder is used for processing snack food, cereal, pasta and pet food. It can provide a closed-loop gravimetric control of material feed rate or an open-loop control for convey rate output and totalization of an uncontrolled or intermittent material supply. The belt velocity is measured from the tail pulley rather than the drive motor. The load cell assembly can be removed and then reinstalled without re-calibration of the feeder.