SUMMARY
A soybean threshing machine was designed, fabricated and evaluated at Landmark University, Omu-Aran, Kwara State, Nigeria, to determine its performance and ease the drudgery problems associated with threshing of soybean by the small scale farmers. Evaluation was carried out with TGX 1448 soybean variety at different levels of moisture contents; 10%, 16% and 22% (wet basis) and at different drum speeds; 320 r/min, 385 r/min, 450 r/min, 515 r/min, with constant mass input of 600g and constant concave clearance of 23 mm. The overall mean results obtained for performance indicators in terms of threshing efficiency, cleaning efficiency, percentage of damage seed, percentage of blown seeds, percentage of seed loss and throughput capacity were 99.51%, 77.91%, 3.72%, 31.33%, 4.43%, and 35.44 kg/h, respectively. The evaluation results indicated threshing efficiencies of 98.96% to 99.88% for the range of the variable of drum speed between 320 r/min to 515 r/min and 99.73% to 99.29% for the range of the variable of moisture content of 10% - 22% (wet basis). The cleaning efficiency decreases (90.81% to 64.25%) as the speed increases (320 r/m into 515 r/min), at moisture contents of 10% and 22% (wet basis). The soybean threshing machine is simple to operate and maintain without formal education and the machine was fabricated from locally sourced materials. The unit cost of this threshing machine was ?69,040.00, which is by far cheaper than imported soybean threshing machines.