"micky" wrote in message
...
I need to put a momentary on switch in my dashboard, and the one I
bought doesn't have a hex nut for the top nut but a round serrated ring
to hold the switch in place.

How do you tighten this? I don't see how fingers can do as good a job
as a wrench did with the hex nut, and pliers will scratch it up.

I could find an old hex nut, but I'd rather use the pretty round one,
if I can.

The usual procedure involves the treaded boss being longer than you need,
you tighten up against a hex nut behind the panel and not the switch itself.
So you would screw the knurled nut on so the thread is only just not
showing, then tighten the hex nut behind the panel.

In the metal shop segment in my first year at college, one of the exercises
was fabrication of a spanner with one jaw serrated and the other smooth.
This would do either knurled or hex nuts. Can't remember seeing any
commercially produced, but I can't remember ever bothering to look.

For hex nuts on front panels, one company had specially made spark-eroded
tools. literally a length of steel bar, drilled through to accommodate the
threaded boss and spindle. The hex recess was spark eroded just shallower
than the nut so the tool never touches the panel.