A height of cut adjustment assembly for a robotic mower (100) includes a height of cut drum (150) secured to a bottom chassis (104) of the robotic mower (100) and having internal spiral threads (148), a motor cup (142) supporting a cutting blade motor (134) and having external spiral threads (143) that engage the height of cut drum (150), and a blade shield (140) fastened to the motor cup (142). The blade shield (140) and the motor cup (142) may be rotated to change height of cut. The blade shield (140) and motor cup (142) may be rotated one revolution to move the motor cup (142) and blade shield (140) vertically between a minimum and a maximum cutting height. Detents (149) engage the motor cup (142) with the drum (150) at a plurality of different cutting heights.
