John Smith wrote:
Just a guess based on your description, I may have understood you
completely wrong.

To clarify, immediately next to the shear is a thin bolt (shiny, new
looking), then the large drum case - i.e. the bolt is outside the
case. I have since learned from Tom Stowers that the nut is standard,
so my guess that it might be a spacer was wrong (I was thrown off by
my inspection of the _old_ brake parts, given to me after the new
installation, which does not have any such nut outside the hub, so I
incorrectly guessed that perhaps the bolt threaded into the hub itself -
for whatever reason that old nut was not included with the old parts.)

Jack