Does anyone have a feel for the flatness of Portland Cement when poured in a standard/typical way? Say, for example, that I wanted to pour a cement "cube" (20"x 18"x 19.25") in a mold. How flat would the top surface be without any special procedures?
Background: I am going to mount a forceplate on top of this cement block and I am trying to determine if I need to specify the flatness tolerance in the drawing.
Is there somewhere I can look for this information?