My orifice plate in my is 2.306" It's hand made so it's not perfect, but it's pretty dang good if you ask me. The sharp edge is not cut you sharp, but I wouldn't want to fall on it.
My question is Generally what kind of flow rate would I be looking at with 12"h2o across a plate this size?
I know there are variables but I was just wanting some round figures 'til I get an actual calibration plate.