Which fit requires force or heat/cold for assembly due to the shaft being larger than the hole?

An interference fit is characterized by the condition where the dimension of the shaft is larger than the dimension of the hole, leading to a tight assembly that necessitates the application of force or heat/cold methods to achieve proper fitting. This type of fit is used when a strong connection between two components is required, preventing any relative movement between them.

The assembly process for an interference fit often involves techniques such as heating the hole (expanding it) or cooling the shaft (contracting it) to allow for the fitting of parts together. After assembly, the components return to ambient temperature, creating a secure and robust joint due to the compressive forces generated.

In contrast, a clearance fit provides a space between the hole and the shaft to allow for easy assembly and disassembly, while a transition fit presents a situation that can allow for either a slight interference or clearance, depending on the specific tolerances applied. Profile tolerance pertains to the control of the shape and features of parts but does not directly involve the assembly mechanics that require force or thermal methods. Hence, interference fit is the correct choice as it specifically addresses the need for additional measures to achieve fitting due to size discrepancies.