My rotary light switch began moving too freely and not clicking from one setting to the next so it was time to replace it. The earlier 460 model has an all in one unit that at its base has small set screws that crimp in the appropriate wire for that particular light. and a plastic guard that covers them when you are done.
The one I am replacing on the early 463 separates from its base like a plug allowing you to remove the part that wears out and just plug in a new outer rotary unit into the base. Saving you from having to do all the little screws for each wire. This could probably be retrofitted to the older 460s but how often do you really replace one of these.
To access the switch you first remove the vent below it (2 clips on top of the vent) pull it out.
Then pull the knob off the switch, Loosen and remove the large nut. Rotate the unit a bit as it has 2 metal fingers that hold it to the mounting plate. Then fish the unit out through the vent opening.
Unplug the base from the rotary switch part, plug in the new unit and reinstall. I picked up a lightly used 190E switch from the Pick-in-pull which is the same. Have a look at the pics. Hope it helps.
Mark