Abstract: A device (21) for metering the mass flow of bulk material, such as grain or other crop material, comprises a sensor member (51) with a curved surface (53) installed adjacent the outlet of a conveyor (12). The sensor member (51) is mounted for pivotment about a transverse axis (P) and is subject to the moment (M) resulting from the material flow along its surface (53). A spring means (66) is provided to keep the sensor member (51) in zero load position. The displacement of the sensor member (51) is proportional to the mass flow rate. Changing friction coefficients .mu. between the bulk material and the surface (53) will affect the flow pattern therealong, but an array (70) of pivot points can be found about which the measured moments (M) remain substantially insensitive to these flow changes. Alternatively a force component may be sensed of the material flow on the sensor surface (53) in a particular direction.