Recommended Minimum Specimen Thicknesses
A general recommendation for minimum specimen thickness is that the specimen thickness should be greater
than 10 times the depth of the indentation when using a diamond indenter. If you are using a ball indenter,
then the minimum thickness should be greater than 15 times the depth of the indentation. No deformation
should be visible on the underside of the specimen after testing.
Refer to the appropriate standard (ASTM E-18 or EN-ISO 6508) for reference tables listing minimum
specimen thicknesses for different hardness testing scales.