Design of a Manually Operated Rice Dehusking Machine for Smallholder Rice Farmers in Kebbi State

Rice processing at the smallholder level in North West Nigeria is largely constrained by the high cost of motorised milling services and the physically demanding nature of manual husking with traditional wooden mortars, leading to incomplete husking and elevated broken grain rates. This study presents the design and performance evaluation of a manually operated rubber roll dehusking machine sized for use by individual farming households in Kebbi State. The machine uses a pair of rubber-covered rolls rotating at slightly different speeds to generate the friction forces required for husk removal from paddy rice. Drive is provided through a hand-crank mechanism connected to the rolls via a gear reduction system that achieves the required roll surface speed differential of 2 to 3 metres per second. Prototype fabrication was completed using mild steel frame components and commercial rubber rolls sourced locally. Performance tests were conducted using Faro and FARO varieties of paddy rice, and dehusking efficiency, milling recovery, broken grain percentage, and throughput were measured. The machine achieved a dehusking efficiency of 88 percent, a milling recovery of 64 percent, and a broken grain rate of 7 percent at a throughput of 30 kilograms per hour. Total fabrication cost was 44,000 naira. The study recommends incorporation of a winnowing attachment in future iterations to remove loose husks and improve output cleanliness. Keywords: rice dehusking machine, manual operation, rubber roll, smallholder rice processing, Kebbi State.