The "mild" starter motor method described above by CB didn't work for me, the torque of the starter wasn't enough. So, after the advice of Harvey, i proceeded to the advanced version of the method, where you actually you let the bar hit the base unit when you operate the starter. It is the actual shock that starts the bolt, not the torque of the starter. In my case it was a 2 persons job, i was holding the bar and socket while a friend was operating the starter. It took us a few times as i remember. Dodgy, yes, but if you don't have rattle gun, you are not let with many options.