| As I understand it ( I'm sure some one will tell me if I'm wrong) Thread inserts ie Helicoils were developed for RollsRoyce in WW2 so they could strip Merlin engines time and time again.
A helicoil is made of hardend coil wound steel and can be used to restore a tapped hole to it former self.when you buy a kit you get a tap and thread inserts.
The down side to them is they can come out and will |