I use card board or cake drums for my tier separators, so a sharpened dowel will go through them. If you use a thin wooden board then yes you would need to drill a hole. For large cakes I use a wooden board on the bottom tier, but I glue the same size cake drum on top so that the dowel has a place to sink into.
Jenniffer White, Cup a Dee Cakes - http://cupadeecakes.blogspot.com
