That old chestnut again .....
No particular technique I'm afraid - the bolt is a standard right-hand thread UNF bolt.
Remove anti-clockwise - jam the blade with something. The bolt is 9/16", but unless it's COMPLETELY undamaged, knock on (it will be tight - 14mm is a fraction smaller) a 14mm 6-sided socket (such as an impact socket. and the bolt should come out no problem.
I use an electric impact wrench sold for removing wheel nuts for this - works 99% of the time, and no need to jam the blade. Best £20 I ever spent!
phil_saunders(a)bigfoot.com
Phil Saunders
June 2012