It’s a guide for establishing shaft and bearing fits for miniature and instrument bearings, when the expansion coefficients of the shaft and housing are similar or when the operating temperature differentia between them is nominal. In other conditions, modification in fits and internal clearance may be required.
Miniature and instrument ball bearings are used in high-precision applications to mate parts, control movement, and provide rotational and oscillating functionality. Aircraft, medical instruments, computers, flow meters, and pick-and-place robots are just some of the challenging applications they are found in. For example, some high-speed instrument bearings travel at speeds approaching 500,000 RPM’s. Flow meter bearings travel at slower speeds but face a unique set of pressure, corrosion, and environmental challenges. Finally, many miniature bearings are used in pulling and stressing man-made vacuums and the natural vacuum of space.