This tip is a fast way to reset the scale list defaults in AutoCAD, as described in Tip #4386. Note that this AutoLISP routine does not set the scales in a particular drawing, but rather sets up the defaults that you see when you go to Options > User Preferences > Default Scale List.
After you have set up the defaults, use the SCALELISTEDIT command (Reset option) to load these new defaults. Simply load this AutoLISP routine to execute it. The scales included here are generally for Civil use, but you can easily modify the AutoLISP file to load your desired defaults.