Interference Fit Interference fit is defined as the fit established when a negative clearance exists between the sizes of the holes and the shaft. In Interference fit, the minimum permitted diameter of the shaft is larger than the maximum allowable diameter of the hole.

Examples for Interference Fit are: Bearing bushes, small end in the connecting rod.

Spot facing is a machining operation for producing a flat seat for bolt head, washer or nut at the opening of a drilled hole. The tool is called a spot facer or a spot facing tool.
Spot facing is similar to counter-boring, except that it is shallower. Tools that are used for counter-boring can be used for spot facing as well.