Natlek calm down a little, you're seeing a part of a test that was a demonstration of a part of a process, you're not seeing the whole picture. I'd appreciate it if you didn't accuse me of "cheating". There is no cheating, it isn't a competition, it a part of a process that I thought folks might think was interesting. The nail is a dramatic part of it but it's not even the primary part of the actual test. You're just seeing a small piece of the whole picture.
There is a very good reason my test blanks were thick, they didn't have bevels. They were test coupons in a knife shape. There were a bunch of them and they were used in comparative testing to each other to evaluate the effect of certain heat treat tweaks.
There was a matrix of variables leading to a LOT of test samples. Those knife shaped test coupons didn't get bevels.
Yes, it is true the thickness behind the edge can be important. Less so to damage that doesn't go above the edge bevel but certainly when evaluating things like bent bevels and chipping that does go above the bevels. And, in my testing, thickness behind the edge
can affect damage at the edge by changing cut dynamics when the media is thicker than the edge bevel height.
This is the picture that got your shorts in a twist:
This is a picture where the cut was duplicated in a real test blade with normal primary bevels using the at-the-time new optimized 3V heat treat. Incidentally with a
thin edge. As you can see it still did extremely well even with the edge quite thin.
^ those are all carefully controlled 18 DPS
The discoloration above the cuts aren't damage, it's where the softer nail has rubbed off on the harder steel and where oxides on the steel left over from heat treat has rubbed off.
Incidentally this does illustrate a little how behind the edge thickness might have some effect on the edge. You can see the nail was much thicker than the edge height. The blade with the thicker behind the edge thickness would cut with more drag. This might help spread the cut saving the edge, or the higher cutting forces involved might lead to more instability in the cut leading to damage at the every edge. In theory. In practice it didn't matter, as you can plainly see in these two pictures.
There are a few observations I'd like to make
1: holy crap, my old photobucket account still works. how?
2: I have the highest respect for Jerry Busse and Infi. I chose that steel as a gold standard, a goal to reach when evaluating a particular property, gross edge stability in rough use.
3: Infi is tougher than optimized 3V. But optimized 3V is much tougher than most knife steels and has similar edge durability and overall significantly better edge retention than Infi. There are trade offs between the two. They're both very tough and have good edge retention. Personally I would use optimized 3V for most applications because I value edge retention over unbreakability, but there are applications where I would use Infi. I've asked Jerry if I could use it, I have projects where it would be great. It is a great steel.
4: There are a lot of people calling "hype" on subjects they don't understand. Many of these knuckleheads have no ability to control or measure edge geometry accurately enough to form a meaningful judgment. The difference between a knife at 18 degrees per side and one at 22 degrees per side is HUGE and is a variable many don't control. Most. There are a lot of "experts" on the internet with opinions. There are fewer folks who have actually done the homework.
5: whoever thinks their wood chisel can be ground to 18 DPS and then cut a 16 penny nail without much damage needs to put up or shut up. I say you're full of sh*t. It's people making unfounded assertions like this without having
actually done it that mess up otherwise informative threads. 20 DPS perhaps. 24 DPS, sure. 18 DPS (relative to center line, not "measured" with a wedge) in .150" cold drawn work hardened steel wire? I doubt it, show me.
footnote. 3V with the industry standard heat treat was developed for stamping dies where preventing part growth and minimizing risk of cracking and distortion was more important than stability in thin sections. But knives frequently go dull from poor edge stability more than abrasive wear. Particularly in choppers. 3V was a cool steel with a lot of potential but it needed a new heat treat to perform up to its potential in knives. A number of people took educated guesses and came up with something better than standard. I was one of the first. And a group of us collaborating were the ones who developed the optimized heat treat for it. We named this final change "Delta" to differentiate it from earlier incomplete tweaks. It finally reached the levels of gross edge durability in rough use as the gold standard, Infi.
