I just did a quick check and it is indeed around 70mm.
I just used an M3 rod which I cut at the desired length. On one side I have a NylStop nut glued with green Loctite (it is the top side you can see on the pictures).
Andrei Gavrilescu
about 6 years
How long are your screws and where did you find them? I looked at some hardware stores and none had m3 that long. I measured the distance and looks like 70mm.