I wonder what the outcome would have been if the test had been the other way around ie if the SOG had been used to chop the khukuri. My guess is that the SOG would have chipped badly.
Hardness and high Rc values aren't desirable per se; you've got to strike a balance between hardness and toughness to suit the intended purpose of the blade. Otherwise, why bother to draw a temper at all?
Heavy chopping blades have always tended to carry a softer edge than small slicing blades. They sacrifice a little hardness and edge-holding capacity in return for flexibility and toughness.
When I buy or make a new heavy-duty cutting tool, one of the tests I always apply is cutting 18 or 16 guage steel sheet. I clamp the sheet in a bench vise and take a diagonal cut (ie impact at 45 degrees rather than 90) Basically, if the blade chips,it gets retired to the cupboard under the stairs to gather dust, or it gets reprofiled and rehardened/tempered; flying steel chips are an unacceptable hazard, and a chipped edge hinders the cut. If the edge both cuts cleanly and comes through undamaged or with damage that can be fixed without further material loss or heat treatment, the tool is passed fit for active service.
None of my HI khuks have failed this test; they've all cut the sheet without suffering permanent damage. (By the same token, only one of my Kris Cutlery blades has failed; the infamous PoS wakizashi. As a result of these tests, I stopped drawing my own blades to straw/purple and went to purple/blue; since then, I haven't had a failure)
The cutting angle is, BTW, an important factor. A 90 degree contact will do far more damage than an angled one.
For the record; the notion that Japanese nihonto blades have superior metal-cutting qualities that allow them to cut such items as helmets and gun barrels with impunity is, in my experience, a myth. Learned *that* one the hard way...
