This is a question more for the machinists who frequent Wreck Wood.
Today I was assembling some metal frame and bent plywood chairs we
bought. They are held together with threaded studs, flat washers and
those hex nuts with the the white nylon inserts (lock nuts I believe I
saw them labeled at the hardware store). I noticed that on one side
of the nut there is a small round collar, slightly smaller in diameter
than the diameter between the flat faces of the nut.
First, does one put the nut on so this collar faces the washer,
reversed (away from the washer), or does it matter? Second, what
purpose does this collar serve?
More on topic to woodworking, the 5/8" arbor nut on my TS has a
similar design. I've wondered if it is intended to go against the
blade stabilizing washer, or away from it.