Im thinking about a new project at the moment. Does anyone know how accurate the linear rails with linear brushings are from http://www.marchantdice.com/linear/. I've got some really nice ground ball screws from the same company and i wondered if its worth using the rods or if i should use THK rails. I don't really want to spend the money buying THK rails which is why im asking if these are worth using with ball screws but if they have allot of backlash then id rather go THK.