I dont have the catalouge in front of me for the specs, but the coating that is on the strut is flat to within .040" , you can however skim the surfaces that you want to be "true" on a mill. My linear slides are bolted throught the profile itself, I am not done with the build yet, so far there seems to be no flex, I am however going to put more supports across the x and y axis to solve any flex during moments of inertia ,ie when i crash it into the work piece
