I don't know if its practical, but I e-turned the surface on my router's table. Seems very flat, but I'm sure that microscopically its not. And the surface finish won't last.
I don't mind. I used a scotch brite pad with threaded mount and A-9 cutting fluid for aluminum.
I think there were 14 lines of code (with loops and a sub) with a drilling cycle. Table measures 2' x 2' so there would have been 4,000+ lines of code if done line by line.
Anyway, I hope you enjoy the pic