A shaft in a sleeve can form a rotary bearing
This cross-sectional diagram illustrates basic features of a symmetrical sleeve bearing. An outer casing supports a ring of atoms (typically one of several in different planes) that interact with a ring of atoms (again, typically one of several) on the surface of a shaft. With proper design, interatomic forces hold the shaft centered in the sleeve, stiffly resisting all motions except rotation of the shaft about its axis, which can proceed with very little static friction. The casing, sleeve, and shaft would typically form part of an extended mechanical system.
How can symmetry properties produce low static friction?
What are symmetrical sleeve bearings like at the molecular level?
Why are bearings important?
Symmetrical sleeve bearings:
Drexler, KE. (1992) Nanosystems: Molecular Machinery, Manufacturing, and Computation. Wiley/Interscience, pp.284301.