Inaccessible milling?

Maybe this is an oft-asked noob question, but how does one typically mill a
part in which all areas are not directly accessible from overhead as in
normal overhead milling? For example, say I want to mill out a box whose
top opening is smaller than the interior area?









R. William Kichman, P.E.
Kichman Engineering Associates
103 Old Furnace Road
Cornwall, PA 17016-0643
tel/fax 717/270-0714