I dont know the answer, others here mite, but if you dont get the answer you want here,, Id suggest calling a machine shop. See what someone like that says. Or maybe YOU can install some,, OOHHHH Maan,, cant remember the name of it,, Threads ya screw down into stripped threads,, Helicoil! Yeaaaa,, It came to me..
http://www.noblefix.com/helicoil.htmRun Helicoil thru the search engine you use..
I use Startpage. They dont snoop.