Personally, I think you will always get some small amount of splintering with baltic birch (if that is what you are cutting). Least I've never succeeded in not having some. Even drilling a hole through I always end up with some little amount of splintering. The project I am working on currently requires some very clean holes to prevent air leaking. I tried everything I know of to prevent splintering, sandwiches between board, sharp fornister bit, still got a little splintering. I could do it with Okume, but not BB. I finally coated around the holes with epxoy and than sanded, to get the clean holes I needed.