> Does the 7mm correlate to an SAE size?
Actually... no!
Amazingly, there isn't really _that_ great a size difference
between 1/4 inch and 7mm, yet we see this diversity. This
should amuse you:
I just went down to the dungeon and examined a bunch of old
stems (but new enough to use hex keys for the binder bolt) and
here are some examples of what I found:
My oldest Cinelli stem - 7mm
TTT Gran Prix - 7mm
TTT Record - 7mm
Pivo - 7mm for both quill and handlebar binder
Balleri, "sample #1" - 7mm for quill and 5mm (!)
for the handlebar binder
Balleri, "sample #2" - 6mm
Everything else, be they French, Italian or Japanese, uses 6mm.
That includes stems from CTA, Cinelli, TTT, Nitto, SR and a
few unmarked pieces.
So what does this prove? I don't know... but it might
answer Peter Kohler's question regarding why MAFAC did not
include a 7mm key in their little tool kit. That is, even the
bicycle manufacturers might not have known what size key was
appropriate on any particular day of the week. But isn't that
one of the things what makes these bikes so interesting?
Cheers,
Fred Rednor - Arlington, Virginia (USA)