Inner our outer threads? And do you have a lathe? If so you can fix it with a Helicoil. You just chuck the screw up in the lathe, drill it out, tap it so a size bigger and place the Helicoil in to reduce it back down to the size it originally was. We own sprint cars and for is it is always a heart breaker when you strip threads out of a $40,000 aluminum engine block, this is how we fix it.