These are great! If you damage the threads, all you have to do is squeeze the retaining

spring with needle nose pliers, remove the damaged nut insert, and replace it with a new insert.

These Self Locking Nut Plates, floating, variable counter bore, with replacement nut element;

come in both 450 DEG F and 800 DEG F types and are available in 2 lug and 1 lug configuration.