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.