What have you done today with your Austin Seven

[Charles P]

Having worked at a number of engineering companys  over many years .
I have fitted lots of helicoils and always believed them to spread the forces more evenly .this may explain it better.https://media.boellhoff.com/files/pdf12/helicoil-kits-repair-solutions-en-0180.pdf
On some new build equipment they were fitted as standard.
Andy



.

I find them very useful too.

The approach suggested by Zeto works but is difficult if you want to to only increase by the smallest increment. My rule for rescuing damaged threads is to never make the original hole any bigger than absolutely necessary 

c