Hello Metrology forum. I have a parallel bar calibration procedure question. My procedure states that “Flatness and parallelism shall be within 0.0002” in 10 inches”. I would like some input on how you guys interpret this. The way I interpret it is if I have a 30” bar the total allowable deviation should be ([30/10] x 0.0002”) or .0006” but never change more than 0.0002” in any 10 inch section? A colleague believes it means that it cannot deviate more than the 0.0002” stated maximum in any 10 inches but must also stay within 0.0002” over the entire length because it doesn’t state: 0.0002” per 10”. Thanks for any input on this.