We report on experiments in which multiwall carbon nanotubes ~CNT’s ! are manipulated with atomic force microscopy ~AFM! on a graphite highly oriented pyrolytic graphite ~HOPG! substrate. We find certain discrete orientations in which the lateral force of manipulation dramatically increases as we rotate the CNT in the plane of the HOPG surface with the AFM tip. The threefold symmetry of these discrete orientations indicates commensurate contact of the hexagonal graphene surfaces of the HOPG and CNT. As the CNT moves into commensurate contact, we observe the motion change from sliding/rotating in-plane to stick-roll motion. The interaction between two bodies in contact is ultimately determined by the interaction between atoms. The arrangement of the atoms in two interacting surfaces has been shown to play a critical role in the energy loss that occurs when one body slides over a second both in experiment, 1,2 and simulation. 3‐5 In particular, in the case of two contacting solid crystalline surfaces, the degree of commensurability has been shown to have a clear effect on friction. 6‐8 Understanding the effect of these atomic interactions on energy loss 9‐12 and object motion is important for designing lubrication strategies and self-assembly processes, and will determine the forms of atomic-scale actuating devices. 13 Current microelectromechanical ~MEMS! devices have features typically in the size scale of ten microns, and gears have been fabricated with teeth measured in the same size range. It is of great interest to understand the ultimate scale of actuating devices, and in what manner atomic interactions will play a determining role. 14 Atomic force microscopy ~AFM! manipulation studies provide unique opportunities to probe the mechanical behavior between objects in that more motional degrees of freedom can be accessed ~sliding, rolling, rotating in-plane! than in tip-on-substrate friction studies. Whether in the context of nanometer scale mechanical devices, biological systems, or the basic understanding of energy loss mechanisms in frictional processes, it is of interest to study both sliding and rolling contacts and why a system prefers one mode of motion over the other. In the present work, we describe experiments in which we are able to controllably tune the commensurability between the two contacting atomically smooth crystalline surfaces. As a model system for such studies, CNT’s and highly oriented pyrolytic graphite ~HOPG! offer a well defined geometry with atomically smooth surfaces that can remain relatively clean in ambient laboratory conditions. We show that the interlocking of the atomic lattices in the contact region of two bodies increases the force required to move the CNT, and can determine whether the CNT slides or rolls. In essence, the atomic lattice can act like a gear mechanism. Our evidence for rolling motion has been published