Through mortices on the back of the fence (bottom of
http://www.patwarner.com/router_table.html page) were cut with a 1/4"
cutter to 1-1/16". Have gone deeper but indeed this is on the fringes
of what a router can & should be doing.
Must you? Use a a good plunger, DW 621 for example, plunge ~ or
1/16"/pass and get long cutters (air trimmer solid carbide) from
Southeasttools.com .