Never done any of the other suggestions... Sharp chisel, hit the bolt on the head with the chisel making sure you're hitting it anti clockwise and this will shock it loose, then just screw it out. Always works.
use the power of the force ... works everytime for me really though, all the above. make sure the allen key is seated properly in the head next time dont worry, everyone has done it !
[sub]i have a tool that you tap over the outside and it cuts into the head of the bolt and you just undo it ith a ratchet[/sub]
if its not tight you can sometimes get away with using side cutters one jaw inside the head and the other on the outside. grip tight and turn ...
In this situation what I normally do is swear a lot, have a cig, swear at the bolt itself again, maybe hit it with a hammer. Then p*ss on it.
lol. Managed to get it off. Made a notch using a screw driver n hammer, then bashed the sh*t outa it till it came off
