Correct nut thread for Altec 9842 cab

I'm looking for some replacement mounting nuts for the 12" drivers my 9842s. It looked like a standard M5 nut but on closer examination the nut size is correct but the thread doesn't match. What's the correct part for this?

Thanks :-)

A 10-32 is close in size to an M5.

Thanks! I'll track down a 10-32 bolt and give it a try.