If the two parts assembled below should allow shaft free rot

If the two parts assembled below should allow shaft free rotation which one you suggest use ? (Choose one from (a), (b), and (c) in the figure below) If the two parts assembled below should ensure accurate locating relationship what is your suggestion ? (Choose one from (a), (b), and (c) in the figure below) If the two parts assembled below should allow higher load be transmitted through the assembly which one you suggest ?(Choose one from (a), (b), and (c) in the figure below)

Solution

1) If the two parts has to rotating freely, independant of one another, it should be a loose fit. (a) is a loose fit, because the lower limit of the hole is higher than the higher limit of the shaft.

2) If we have to ensure accurate locating relationship, the two parts should not move independant of each other. A transition fit will be needed. (b) is a transition fit

3) For heavy loads, the joint should be real tight. An interference fit is needed, which is option (c), because the lower limit of the shaft is higher than the higher limit of the hole.