Surface temperature can’t be overheat, less than 120 ℃.

Surface roughness should not be too large, otherwise it will cause errors. The surface of the work piece must be exposed metallic luster, smoothing and polish, without oil.

The specimens with 2-5kg or thin-walled specimens overhangs should be supported with some object in order to avoid the pecimen deformation ,bending and movement caused by impact , for medium-sizedwork piece ,it shall be placed on a flat and hard surface, the sample must be placed absolutely smoothly, without any shake, for heavy samples more than 5kg, it can be measured directly without any support

 Portable Leeb hardness tester has strict requirements for sample thickness , the minimum thickness shall comply with regulatory  (see instructions).

For work piece with hardened layer on surface,the depth of hardened layer should conform to regulatory..

For lighter parts,please make it tightly coupled with support, two coupled surface must be flat and smooth, the coupling gel should not be too much, the direction of the test shall be perpendicular to the coupling plate; if the work piece is a large plate, pole or bending material, even if the weight and thickness is ok ,it may still cause deformation and instability, resulting in test values error, it should be reinforced or supported at the back of the test points.

Magnetic of work piece should be less than 30 gauss.