Dude, wtf, stop posting 10 threads with the same question! Place the pivot on the side where you want to the head to mirror. Hold 'v' while moving the pivot point and it will snap to vertex. Or if the centrev of the head is on the grid axis you can hold 'x' to snap to to grid. okay i must not be getting what you guys are saying cause moving the piviot is making the offset worse not better