The Delta protocol is one of the low temp tweaks. I was doing development work on the low temperature tweaks (a heat treat that does not use the secondary hardening hump and addresses retained austinite through rapid quench to cryogenic temperatures instead) for years. Keffeler was also. This is how we got to know each other.
There was a batch of 3V that did not have normal heat treat response. This was back when I was making the original Shiv many years ago. I had done experiments with prequenching D2 with excellent results and I applied what I knew from D2 to 3V and it addressed the issue. But not for the reason that I thought. (prequenching is performing a heat treat on a complex steel at a lower aust temp and then performing another heat treat at a higher aust temp. This has the effect of reducing grain size but it is risky because it is possible to dissolve the carbides pinning the grain boundaries and actually have explosive grain growth if done improperly. This is specific to complex steels whose grain size is otherwise baked in) It turns out that an anneal carried out over a 24-hour period was all that batch really needed. I suspect it was highly spheroidized which affected the availability of carbon to go into solution and had an effect on the final heat treat. Interestingly, this problem could not be found with a hardness test, it was only apparent in an edge stability test which is where I noticed it, Dan noticed it, and Guy noticed it. Because we were all testing our work and we saw the problem. The problem was probably not even noticeable to folks using a high temperature protocol (The standard for tool and die) not because it wasn't present, but the standard heat treat was already chippy mushy and would have appeared relatively normal. The three of us went together and did the work to do an exhaustive development cycle with the heat treat of CPM 3V. I spent most of one winter solely on this process. I'm not a metallurgist. Other than a couple materials and processes classes I took at NC State back in the '90s, most of what I know about metallurgy is from the internet and books. But I had a significant professional background in product and process optimization at this point because I had just come off of a 10 year stint at TecRep Engineering as the product design manager. We had a process of creating a matrix of variables and (more or less blindly) modifying variables and measuring both the outcome and the interaction on each other. The best example of this was our foam generator development work we did for a chemical company in Greensboro. But that's another story. But the process for developing the Delta protocol was as simple as introducing and modifying variables, the timing of steps, adding steps, and effectively evaluating the outcome which meant standardizing on a sharpening angle, test media, and eliminating variables such as overheating the edge etc in an effort to maximize the signal to noise ratio. It is a very stringent process based on observation and comparative testing kind of like the Mohs hardness scale where this mineral scratches that mineral. You have test standards and you run them all through the same media and then you look at the edge under bright light and magnification and objectively observe which edge has accumulated the most damage - edge loss. I had run D2 through this process before. The most significant finding that I can share with you is that abrasive wear resistance is largely built in, toughness in 3v is largely baked in unless you screw it up (which is entirely possible which is actually why I started making videos in the first place, to demonstrate that I had not screwed it up) and that edges don't really go dull through just abrasive wear but through edge loss-damage that can be summarized as edge stability. Which can be broken up into fine edge stability and gross edge stability. Conventional 3V has a chippy mushy edge. When using the secondary hardening hump this is due to a soft weak carbon lean martensite attempting to support a growing carbide volume fraction. This is why I don't like edge retention testing that is based on where resistance such as lightly sawing at abrasive cardstock to try to determine which steel and heat treat have the best edge retention. That isn't edge retention for most people. But I digress again.
I did the majority of the work and claim credit for the development of this heat treat, but the three of us went in together and the three of us have access to that protocol. Peters was not able to duplicate it at first and had to make some changes to their process equipment but after a while they got there and they are frequently able to apply the process better than I can now, depending on the knife geometry. Probably because my heat treat set up is worth about $5,000 and theirs is about half a million dollars.
There have been improvements to both the steel manufacturing process and the heat treat process since we originally released the new Delta protocol, if anybody has noticed, the work today is the best it has ever been.
Anyways. Very long story short. The early low temperature tweaks were being openly discussed on this very forum and also hype free blades and some other places and those original low temperature tweaks are freely available at Peter's heat treat, and their heat treat is particularly well suited for it after their development work with us with this particular steel. They're good at it.
So, when they are saying they are using a variation of the delta protocol, this is essentially true. They're using one of the low temperature tweaks that we used to use that is freely available to anyone who gets their work heat treated at Peters. It is a very good heat treat. The Delta protocol is measurably better and (also very important) very consistent from heat lot to heat lot. But the Delta protocol is not enormously better than the available low temp tweak at Peters. It developed from it, they are related, and you would have to have two identical samples in hand side by side to see the difference in use. I have no problem with their statement.
