I have a friend that works on jetskis that 'tried' to bring me up to date on a great way to fix damaged threads. He proudly said that taking a bolt or stud and cutting flutes into it with a cutoff wheel works better than a tap for restoring damaged threads. He wanted to demonstrate it to me in my shop. I was a little insulted and refused to let him show me. Modern taps have evolved into engineering masterpieces with a wide choice of materials and an almost limitless amount of design features. To cast all that aside and see his demo was insulting. To think that a blob shaped burr on a bolt or stud should even be taken seriously, so I just shook my head and flatly refused to see his demo. Would you have let him proceed or do what I did?