We purchase all of our steel plate professionally ground and certified by our material suppliers. Hobbyist class plates are blanchard ground and the professional class plates are finish ground. The blanchard grinding is +/-.0015″ parallel over 12″ and the finish grinding is certified parallel within +/-.0025″ over 24″. If you are having problems with getting your plate flat enough for your requirements be sure to stone your machine table and clean it thoroughly before you install your plate. All of our plates are hand stoned top and bottom after the deburring to remove any irregularity before they leave our facility. Need it better? Check the SUPER GRIND box when you choose your options for your plate. Tosa Tool: Raising the bar.