"David Billington" wrote in message
news:51201a3b$0$4494
I'm buying industrial fasteners to ISO spec. Auto fasteners can be
anything the maker wants due to quantity. For instance M7 is not a
preferred size but is more prevalent these days in the auto industry
as the jump in strength between M6 and M8, both preferred sizes, is
significant and the intermediate M7 can perform the job where M6 is
insufficient and M8 overkill.

The clamping screws on my Swiss Multifix lathe tool holder are 7mm. I
found replacements for the damaged ones in an auto parts store. The
heads are 11mm which a 7/16" wrench fits nicely, so I can use the
antique wrenches I've collected to go with the lathe.