A horizontal fluent material dispenser for the even dispensing of a metered quantity of powder. A hopper holds the powder. The hopper has a mixing portion with rotating beaters. A horizontal conduit is coupled to the hopper and receives powder from the hopper. A screw conveyor—or auger—within the conduit transfers the material through the horizontal conduit. A knife assembly, disposed at the distal longitudinal end of the screw conveyor, breaks off a continuous and even flow of powdered material out the discharge opening. A modular screw conveyor assembly is disclosed for changing the material dispensing rate range without changing the conduit diameter. A dual drive mechanism is also disclosed for independent adjustment of the rotating beater speed and the screw conveyor.