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Managing crop load by removing bloom in tree fruits, such as cherries, apples and stone fruits, is reported to result in larger fruit at harvest and in most markets demand a higher return for the producer. When compared to bloom thinning by hand, mechanical thinning has the potential of reducing production cost and demand for a short term labor pool; and offers a new tool for organic production of tree fruits because few chemical thinners are available or reliable. The thinning actuator is the core element of a mechanical thinner and determines the performance. The aim of this study was to investigate the characteristic of thinning actuators with defined configurations to provide critical information for industrial commercialization. An indoor experiment scenario was developed to mimic the different orchard thinning conditions and evaluate the torque, speed variation and power consumption. Five different types of strings were tested on the developed platform. Results showed that rotating speed was decreased more than 50% when strings with larger stiffness (M1 and M2) were applied. The maximum torque values of each type of string (M1, M2, M3, M4 and M5) were 0.98, 0.80, 0.63, 0.54 and 0.34 Nm, respectively. The average power value of each type of strings within the medium actuator speed range (800-1200 RPM) were 86.7, 57.1, 46.3, 32.8 and 21.3 W and power value highly correlated to the rotating speed of the thinning actuator.