Use the WSB cleaning bottom router bit for woodworking projects that require clearing out the bottom of trays or recessions. It is great at removing a lot of material. Start from the middle and work your way to the edges. The smoothness of the bottom will depend of the flatness of the piece you are routing and how well the router is supported. Bit size is 1/2" X 1/2" (see picture diagram for detailed measurements).
WSB router bits are manufactured to high quality standards and come with a 100% satisfaction guarantee. If you aren't satisfied, return them.