I'm the guy in the video and I'd like to address some questions.
Is that a request?
Because I have an old-spec GSO-4.1 with the new HT protocol. I can polish it up with 18-dps and look for a 16 D nail to cut. My guess is that Nathan is having Peter's do the same HT with his as they are now doing on Guy's.
I will say that when i used my old GSO-10 clearing brush and managed to chop hard into a "tree spike" (fence staple), I did some sizeable damage to the edge not unlike what is presented in this video.
One thing i would worry about is whether or not the edge-shoulder thickness is coming somewhat into play in this particular comparison. Remember that the GSO-4.1 is going to be 0.02 - 0.03" thick back only ~0.06" from the apex - that is the shoulder height with ~18-dps edge, beyond that the wedge is much thinner at only ~5-dps. That nail is 0.150" thick = ~2X the height of the S!K bevel. Beyond that edge-shoulder, the blade is no longer presenting as much wedging-force to split that nail. The 18-dps bevel on the Busse and even moreso on Nathan's test-blade go up much higher, i.e. the 18-dps wedge is present for perhaps the entire thickness of the nail, pushing it apart with greater force during the cut and utilizing the added strength of that extra material behind the edge.
"But Chiral, the damage on all 3 is restricted to the edge-bevel, the S!K blade just has more damage." Yes, mostly due to lower hardness (weren't those HT'd at 58Rc vs the new ones are ~60Rc?) - the edge is being compressed/bent out of alignment by the strength/resistance of the nail... But a nail is not prone to folding away from the edge during a cut like a string under tension, it is pressing against the blade (w)edge the entire way through the cut, and the S!K wedge thins out in the midst of it, with less material to keep the nail from pinching the edge. The Busse and NtM knives don't do that, their wedges continue to push the nail apart, reducing this "pinch" on the apex as it continues.
Maybe I'm wrong, maybe it's not a factor... but I always get antsy when geometry is not fully controlled in such demonstrations. *shrug*
This was a legitimate question and one I set out to answer yesterday.
I'll let Guy tell you folks how I fit into this, but it's worth noting that all of these tests samples are his patterns.
For the development I wanted to see minor changes caused by subtle HT tweaks, so taking primary bevel out of the equation removed a variable. But, I agree, when it came time to actually compare the result to other standards the edge thickness behind the edge could be significant, like you say. I considered that and ran the final protocol in a conventional knife and cut the same nails with it. This one is .034" behind the 18 DPS edge, which is slightly thinner than the control.
New protocol run in blade geometry like the industry standard control shown on top. It behaved the same as the other test blade with the same HT. So, while this was a good question, in this case the issue of primary bevel and thickness behind the edge did not effect the result.
The industry standard control blade measured HRC 60. The Busse measured 59. As it is, the new tweak is yielding 60-61. These are all pretty similar measured hardness, with the industry standard in the middle of the range.
And to be clear about bringing a Busse into this. When I was developing a HT for D2 I had a Dozier in the standards. When developing a HT for a large rough use knife it makes since to bring a Busse into the mix of reference standards, INFI is a gold standard for certain attributes. I have nothing but respect for his work.
I's also like to point out that folks need to have some perspective. It's not like the industry standard 3V gave a poor performance here. Take a Buck knife and sharpen it 18 DPS and run it through a 16D nail with a 4 pound hammer and see what happens! Everything is relative.
edit to add: I'm sending that test sample, unaltered, to forum member Cobalt. He'll be able to confirm this is legit.
