We investigate a Casimir nano system composed of two thick dielectric disks separated by a thin gap. Initially the two disks have the same surface dielectric distributions. Two disks have quadratic regions. We use scattering approach in the weak coupling limit and show that the top plate experience a torque τ(θ) if it rotates about its axes by an angle. Consequently we will be able to calculate τ(θ)∝sin(θ). We also study the dynamics of the system and find that the average angular velocity of the top disk is not zero.