You may want to have a chat with these guys they make an entire lathe out of concrete, not just the footings or the base and they do attach the linear rails straight to the concrete. Aparrently they were used all the time in WWII (along with concrete ships) because all the metal was going into things that kill people.

MAKE | The Concrete Lathe Project

http://concretelathe.wikispaces.com/...esign+Drawings