Operating according to the Rockwell principle (ASTM E-18 - ISO6508) the AT130D series, is not influenced by deflections.
The reference point for the measurements is the surface of the component itself.
Surface preparation is needed only where the indentation takes place. With an easy actuation of the lever, the preliminary force and additional force are applied.
With the return movement, the additional force is removed, and the hardness is calculated. The complete test takes no more than 3 seconds (a few seconds longer for very soft materials).