What type of fit results when shaft and hole sizes are close, resulting in either small clearance or interference?

The type of fit that occurs when the sizes of a shaft and a hole are close, allowing for either small clearance or interference, is known as a transition fit. This type of fit is characterized by the potential for slight variations in the dimensions of the components such that they may fit together with either a little space (clearance) or a slight press (interference). This allows for flexibility in assembly and can accommodate variations in manufacturing tolerances while still ensuring a functional connection.

In contrast, interference fits occur when the shaft is slightly larger than the hole, leading to a tight fit that requires force to assemble. Clearance fits, on the other hand, are designed so that the shaft is smaller than the hole, ensuring ample space for easy assembly and movement. General tolerance refers to the permissible limits of variation in dimensions, but it does not specifically define the relationship between the sizes of components as fits do. Transition fits provide a balanced option for applications where a secure but not rigid connection is necessary.