Somewhat relevant, though a lot of my work isn't on forums like this where originality and excellent work is preferred.
On my CB and CD175's I used to replace exhaust studs that had stripped out with 1/4" BSF studs, being 26tpi they are very near to M6 pitch, but being 6.35mm would cut into the head to form a strong fix. (1/4" cycle thread works the same - 26tpi)
And on a race bike I spanner on we regularly pull head studs out of the crankcase and need a quick repair to get back out for another qualifier or race. I carry spare modified studs - weld up an M10 old stud, machine it to 10.7mm, then machine a taper thread tapering down to 10.0mm, this can be fitted using two nuts.