Testing for Overheated Edges

[KnifeGrinders]

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From SET testing we have seen that for basic use knives there is little performance difference in edges HRC 52 – 62.  They all roll.  Even if the edge was softened slightly it’s probably still well within that hardness range.
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I see a tendency to misinterpret SET-testing results, not personally Grepper, but I've heard opinions similar to what Grepper says many times and this conclusion simply can not be drawn from SET testing.
The BESS Set tester with a standard 150-gram steel roller at 10 degrees to the edge is good for testing the so called "working edge" sharpness, i.e. in the range of 300-500 BESS.
A single forward-backward SET roll moves the edge into this range, e.g. from 50 BESS to 250-300 BESS, and nothing like that ever happens in real cutting - the impact is too serious to obtain any meaningful data under 250 BESS, where the sharp and very sharp knives live. 
Ceramic edges don't roll, but respond the same way - a single SET roll drops a 12 dps edge sharpness to 300 BESS, telling us that the impact is too much for the thin edge. I posted data on SET-testing of ceramic edges on this forum.
The standard BESS Set tester can not be used for testing edges sharper than 250 BESS, it is just not fit for that.

As I've mentioned several times by now, the difference imparted by common sharpening and honing methods matters in the initial performance of very sharp edges in the under 200 BESS range; these differences level out  when the sharpness drops over 250 BESS.
When you think of sharpness as the edge apex width, it becomes pretty logical - subtle impact affects the thin edge. In fine honing, the effected area of the apex extends down to only 1.5 micron.
In applications where the sharp blade is a requirement, it all matters and matters a lot.

As you could see in our study Effect of Felt and Paper Wheel on Edge Retention, using a copper roller in the BESS Set tester allows to accurately test edges in the under 200 BESS range, but this is a separate story.