Tosa Tool does not qualify plates for a relaxed flatness tolerance. The plates are ground parallel to the specified tolerances.  However, we do evaluate and process the raw material in a specific way so that when the fixture plate is secured to the machine table, it’s “flatness” will be the result of the thickness tolerance plus any deviation, level, or tram error in the machine table. If you need the absolute best flatness and parallelism try SUPER GRIND!