The boss on the mag cases is quite small and we don't like the idea of re-tapping and fitting a helicoil as the thickness in this area is not so good and if it fails you are then left welding up the case.
If you look carefully into the case there is a depth of around 35mm below the thread which has not been tapped and is the correct diameter for an M22 x 1.5 thread.
We have made an M30 x 1.5 fitting with an extra 20mm of M22 x 1.5mm thread.
By tapping down into the existing hole the new fitting is straightforward to install and solves the problem without taking a risk with a helicoil.
We made the new fittings in 6AL4V Grade 5 Titanium and they have worked quite well.
