X hammered this. That is, he hammer-did it. When - pli is final in a complex, then something is being claimed to be used for some purpose. The target of the action need not be specified, or there may even be no state change. Behaviour is a category of animal motion that need have no conscious goal or end, such as a sneeze or tic, or of which one is largely unaware, such as one's manners.
Action is always with a conscious goal.
Thus - dui is used to indicate an action that determines or discloses a previously unknown property of something. If the second place is to be a point of departure, use - kaa . English usages can be misleading here. Another rule which we found useful in complex-making is to use no nu fu etc. But when the scope of the operation is short, we use nor nur fur etc. and make it part of the word we are building.