Arun KumarAchugatla Kesav Kumar2019-08-162019-08-162019-07http://krishikosh.egranth.ac.in/handle/1/5810121925A machine tractor operated front mounted twin conveyor onion digger consists of main frame, digging unit, conveying unit, power transmission unit, front mounted frame and lifting and lowering unit. Different components such as blade, bevel gear, and single acting hydraulic cylinders, pulleys, propeller shaft and V-belt were selected as per the design requirement. The machine has five blades made of mild steel 320 150 12 mm size were bolted to the base plate instead of one single share to strengthen the share. A onion and soil were separated with conveying unit consists of 90 mm diameter and 500 mm length made of galvanized iron 4 rollers were 25 mm mild steel shaft was fitted with the help of bush bearings. 5 ply rubber belt was fixed on the roller and MS flats 20 3 mm were fixed spacing between two flats 25 mm based on equatorial and polar diameter of onion, over the rubber with the help of nut and bolt. During field operation the conveying unit was not touch the ground for providing depth wheel each rear side of the conveyor. A power transmission unit consists of a gear reduction unit, V-belt and pulley arrangement and 40 mm diameter of propeller shaft. A power transmission unit consists of a gear reduction unit, V-belt and pulley arrangement and 40 mm diameter of propeller shaft. The machine has lifting, lowering and depth has controlled with the help of two single acting hydraulic cylinders 50 mm outside diameter and 32 mm piston rod diameter. The Biometric and physical properties of onion bulbs (Agri found light Red) was found average equatorial and polar diameter, plant height, neck thickness, weight of onion dry leaves 36.19 and 37.19 mm, 284.05 mm, 6.808 mm and 30.198g respectively. The average soil cone index, moisture content and bulk density (before transplanting and harvesting) of soil observed to be 1 kg/cm2, 17.22,12.58 % and 1.50, 1.38 g/cm3 respectively. During field evaluation was found to be maximum percentage exposed bulbs and minimum damaged bulbs as 82.55% and 13.51% respectively, at forward speed of 1.5 kmph and conveyor speed 0.55 m/s. The theoretical field capacity of machine 0.24 ha/h, actual field capacity 0.21 ha/h and field efficiency 87.46%.ennullThesis