A bearing designation typically indicates what type of size metric?

In bearing designations, the bore size is a critical metric that informs users about the inner diameter of the bearing. The bore size refers to the diameter of the hole through which the shaft or axle will pass. This measurement is essential because it must match the shaft's diameter for the bearing to function correctly.

Bore size is often the first figure listed in a bearing designation and is crucial for ensuring proper fit and function within mechanical assemblies. When selecting a bearing, knowing the bore size helps prevent misalignments and ensures the bearing will support the intended loads effectively.

Understanding the bore size allows millwrights and technicians to select the right bearings for their applications, ensuring optimal performance and longevity in machinery.