MUK student makes manual rice thresher

By John Kasozi
Having grown up in Iganga, one of the leading rice growing districts, Ronald Musobya started threshing rice at a tender age.
During one of his secondary school holidays, Musobya severely bruised his palms while threshing rice.
“My palms got swollen, with a lot of pain. Using hands to thresh rice is a custom that has been on in Busoga for a long time,” he says.
According to Musobya, it is that pain that drove him to think of developing a rice thresher.
“Many farmers in Busoga use hands and sticks to thresh rice. The percentage of broken rice is extremely high. The chances of unwanted matter mixing up with rice is also high and time consuming,” says Musobya.
Musobya, who has completed his degree in Agricultural Engineering at Makerere University, started generating ideas about the thresher during his second-year field study, while working with Kibimba Rice Project under TILDA Uganda. While there, he came across a dismantled rice thresher in the store and studied it and gained more knowledge.
“In my final year, I used similar principles to carry out more research, after which I came up with a simple prototype manual rice thresher. I submitted the same project for the award of my degree,” says Musobya, adding, “Currently, the thresher has been approved by Makerere University’s Department of Agricultural Engineering and has been tested and bought by farmers.”
He says the thresher is operated by two people. One pedals it while the other feeds it with rice stalks at the opposite side. The person pedalling sits on a detachable seat screwed onto the thresher.
The pedal system is simple and similar to that of the bicycle. It has a chain and two sprockets.
Maintenance is done by greasing the chains, bearings and tightening the loose bolts and nuts.
Musobya says the threshing drum is pedalled until it gains full momentum at the speed of 400 revolutions per minute.
“Thus, a person feeding the hopper (bucket) has to hold the rice stalks until the drum attains full thrust. At that point, the spikes on the rotating thresh drum start brushing off rice grains from the stalks.”
Musobya says during an on-station testing, the machine threshed 221 kilogrammes of K85 (Kaiso) rice per hour on average, at a threshing efficiency of 93%. Threshing efficiency is how much rice is removed from the stalks.
Musobya says the amount of rice threshed depends on the maturity of the crop and moisture content.
Harvesting rice at the right time and ensuring that the thresher is well operated reduces the 7% loss.
With the increase in the number of people growing rice, the machine will lead to improvement in the quality and quantity of rice.
The thresher can be easily fabricated and modified since it is not made of special material.
“Fabrication material costs about sh200,000, while the machine costs sh350,000, but the price will reduced as more machines are made,”he says.
Musobya hails his lectures for his success.
“Without the guidance of my two supervisors, Eng. Joshua Wanyama of the Agricultural Department and Alfonse Candia of the Agricultural Engineering and Appropriate Technology Research Institute, it would not have been easy.”
Ends