Sometimes I have to whack it hard with a 5-lb mallet. I put a 6mm allen-socket into the bolt and hit it HARD. Be careful not to unscrew the bolt all the way from the wedge, just 2-3 turns to it's raised above the top surface of the stem. You don't want to damage the threads on the bolt & wedge. Well, I guess it doesn't matter if you don't plan on using the stem again. Having the bolt engaged with the wedge helps all the hammer blows go into the right areas.