Will an 9/16ths stripped bolt extractor work for a 14mm?
 

I'm looking at these:
http://www.sears.com/shc/s/p_10153_1...0070921x00003a

And it says that bit number 8 works for both 9/16ths and 14mm, but last time I tried to use an 9/16ths for a 14mm it didn't end well.

Will it work anyway?

Yes it will work. I frequently interchange both 9/16th and 14mm sockets, especially if they are a 6 point. The 9/16 is only .2875 mm bigger than a 14.

Yep. I use 9/16 on 14MM stuff all the time.

I was not aware that you really got that precise with extractors. I always just drilled the thing and used something as small as reasonable so that there was plenty of the bolt around the drilled hole to handle the force.