ive never used one but cant imagine how to fix a thread with it.
i see hte grooves on it but how do you go about going around the thread and straightenin it.
you just file it around the bolt or stud, the file is cut for the size threads you are using, so u just file it straight and it cleans and corrects any messed up threads, probly easier to see one used than try and explain it, even know its pretty simple
id rather use them than a tap if i can help it because they are alot easier to use, and they are quick