Re:
I've just looked back at the two Ti quill bolts of different lengths that I've obtained for my Velocity stems. So far without problems and both for 1 1/8th" stems.
1992
M8 bolt fits a Titanium velocity stem @135mm
1993
M7 worked for my chrome velocity stem @60mm
I had the original bolts in steel so was able to match. I may even have a spare Ti 60mm bolt on hand that I could sell on.
The 1991 Velocity is longer still at 150mm.