I am making some door casing in a victorian style and I am cutting multiple grooves in the face of a 4" wide piece of cherry. I am using a v groove bit on a router table. The problem I am running into on a few pieces is getting the wood to lay perfectly flat on the table and get a uniform depth groove along the whole length of the board. The problem is a few boards are not perfectly straight and it is hard to push them down against the table and I get a shallower groove than other spots of the board. I have pushed down as hard as I can as it passes over the bit but it still is not cutting a uniform depth.
Does anybody have a tip? I don't have a power plane plus I don't want to make the boards any thinner, they are all finished to 3/4" and I want to keep them like that.