I measured the ball on my 7D and it measures 4.62mm or .182in.
I would look for a heli or rc car end link or linkage end that would work.
a post on RC groups said the Dubro 2-56 link works, remove the ball and snap on. DUB-367
what people need to realize is that Tucker, Hanity, and all the others don't REPORT the news they SELL the news, all of the news agency's SELL the news or what they want you to believe is the news, old school journalism is dead and gone.