A careful read of the above last few lines, starting with "however", suggests they agree entirely with my statement, that it is all relative, and only self referencing.

In the case of trying to use such a gizmo on an old Ruana knife, you would already need probes calibrated to the material of the blade precise material, in order to even begin to get a reading.

But, most of what that machine is hoped to provide, must be already known, before testing even began.

You would need to know Rudy's exact alloy, and engineering data on that alloy forged Rudy's way, to even start reading hardness of a blade of Rudy's. And the amount of forging in various areas will vary, and then so will the elasticity of the metal, as will also it vary due to his heat treat, and draw down of hardness on his blades in various areas.

In short, you would need all the answers before ever looking for them. It will only give a reading relative to something already known. Any reading would need be stated, "if it is this exact alloy, and forged this much, then it reads close to this metal and hardness. However, if not forged as much, or made of this metal, instead, then Rudy's blade is sort of like this other metal and hardness...but, only right in this spot, as etc etc etc etc".

My read of it, anyhow. Will leave it to the techno types messing with human DNA and creating black holes and anti-matter on Earth, while still unable to even explain or prove various knives cut better and last longer, except with a machine using calibrated sandpaper cards, and which duplicate no normally cut material, nor any normal human movement or use of knife. If they cannot explain THAT, how are they going to explain a blade by Rudy Ruana?