Cam And Lifter Hardness Testing

Rockwell testing makes a dent and then the dent is measured to give a figure. The smaller the dent, the harder the material.

There are more complicated methods, but they cost more. Vickers, or even eddy current systems.

The other thing with most hardness tests is that the specimen has to either be consistent in order to make a meaningful comparison, or the material needs to be thick and flat.

Rockwell and Brinell and others also aren't well suited to surface hardness for case hardened parts or parts with a softer core. It skews the results. Vickers works better for those (microscopic dent), but a vickers tester requires a super high powered microscope and specialty measuring.