Question

What is purpose of clearance in cotter joint?

Answer 1

The clearence is provided due to following two reasons:

First the clearance allow the axial adjustment between the two rods .

the second reason is that when the cotter is driven in the slots the cotter moves till the face of collar touches the collar end of the spigot and the tapered face touches socket end due to clearance.

Hence the cotter draws the two rods closer and hold them rigidly by friction grip