Two types of threshing cylinders, namely cast iron rasp bar threshing cylinder and nylon rasp bar threshing cylinder, were developed and fitted with portable paddy thresher. Each threshing cylinder was tested for its performance in terms of threshing efficiency and grain damage at different levels of factors: concave clearance (15, 20, 25 mm), cylinder peripheral speed (11.7, 14.1, 16.5 m-s-1), grain moisture (13.5%, 16.5%, 19.5%) and feed rate (200, 400, 600 kg-h-1). Comparing the maximum threshing efficiency, minimum grain damage in different combinations was achieved at 20 mm concave clearance, 16.5 m-s-1 cylinder speed, 13.5% moisture content and at a feed rate of 600 kg-h-1. The grain damage occurred at this combination was 2.76% and 1.73% respectively, for cast iron rasp bar and nylon rasp bar threshing cylinders. The threshing efficiency occurred at this combination was 99.95% and 99.93% respectively, for cast iron rasp bar and nylon rasp bar threshing cylinders.

Dve vrste vršidbenih bubnjeva, sa gvozdenim i najlonskim letvama, su razvijene i ugrađene u prenosivu vršalicu za pirinač. Kod svakog bubnja su ispitivani efikasnost vršidbe i oštećenje zrna pri različitim vrednostima: zazora (15, 20 i 25 mm), periferne brzine bubnja (11.7, 14.1 i 16.5 m-s-1), vlage zrna (13.5% , 16.5% i 19.5%) i protoka mase (200, 400 i 600 kg-h-1). Poredeći maksimalnu efikasnost vršidbe, minimum oštećenja zrna u različitim kombinacijama je postignut sa zazorom od 20 mm, perifernom brzinom bubnja od 16.5 m-s-1, vlažnošću zrna od 13,5 % i protokom mase od 600 kg-h-1. Oštećenje zrna u ovoj kombinaciji je bilo 2,76% i 1,73% redom, za gvozdene i najlonske letve. Efikasnost vršidbe u ovoj kombinaciji je bila 99,95% i 99,93% redom, za gvozdene i najlonske letve.