Trying to put my SI cage on and can't get the thrust nut off. Am I missing something? I thought it was a 14 (or) 9/16th socket, but doesn't seem to grab on well enough, slipped off. Both metric and standard socket.

So, before I actually **** up the nut, is there a technique in removing this, or should I throw the bike against the ground and cuss at it a bit?

Arrow marks the spot for clarification. Also, the nut is on the other side, just showing the location for you guys.