A Master Calibration (See Fischer instrument manual) is required to ensure quality datafor peened parts. The base metal standard must not be peened, for anodized peenedparts must be anodized only. A minimum of 25 measurements on the base metalstandard for zeroing and 10 measurements for measuring shims is required. Thisprocess requires 4 shims of nominal thickness of 1, 3, 10 and 30 mils (25, 75, 255 and760 μm).