David Pye's blog series on hardness testing continues ... and concludes with part 11.

David Pye's series on hardness testing continues with part 10.

In 1939, Frederick Knoop and his colleagues at The National Bureau of Standards submitted an alternatively designed indenter based on a rhombohedra-shaped diamond whose long diagonal was approximately seven times as long as the short diagonal.

David Pye's blog series on hardness testing continues.

David Pye's series on hardness testing continues.

David Pye's series on hardness testing continues.

This is part 5 of David Pye's series on hardness testing.

This is part 4 of David Pye's series on hardness testing.

This is part 3 of David Pye's blog series on hardness testing.

Our discussion on hardness-testing principles continues. In part 2 we will classify some hardness-testing methods.