...and to further confuse me, just after replying below, I looked at AC43.13B and it says this:
7-87. LOCKWASHERS (AN935 AND
AN936). Lock washers may be used with machine
screws or bolts whenever the selflocking
or castellated type nut is not applicable.
Do not use lock washers where frequent
removal is required, in areas subject to corrosion,
or in areas exposed to airflow. Use a
plain washer between the lock washer and
material to prevent gouging the surface of the
metal.
So I still don't get it?
Thanks!
-Jim