When you’re a beginner or unexposed to a new concept even when you’re experienced, nothing seems as connected as it is. The whole idea behind the Unicorn method is not some silo method that comes out of nowhere – it’s evident everywhere once you get a handle on it and then see where it happens. The linen and leather combination in the old days for straight razors was a matter of keeping the angle low but conditioning the apex of the edge to be very slightly adjusted so that hairs and dirt wouldn’t dent it.
A “thin” knife with a appleseed edge (I just learned that watching Forged in Fire!! Always behind the cool kid’s curve) will hold up at the edge very well in cutting and perhaps slip through a cutting task far better. Don’t believe me? Take a thin inexpensive knife and cut cardboard with it. Then, try some fatter knife like a benchmade and sharpen it to some high level of sharpness – the bulk in the blade just creates unneeded work. Cutting cardboard is a matter of slicing, not hacking.
At some point, I bought a metallurgical scope – not an expensive one, just about $425 with a camera. I figured I could resell it when I was done, and if that seems like a high cost, find a catalogue of western-made metallurgical scopes and see what they cost. The purpose was to grade natural stones and confirm that razors would hold up well before I resold them. That phase is over, but the scope turned out to be useful for other things. At some point, I started to look at edges for another reason and I realized that in most cases, the damage in a tool edge is in the first several thousandths of the edge and nowhere else. Before it gets larger, you can’t use the tool. If the damage is greater than that, you have some other large problem to solve that has nothing to do with sharpening.
Here’s an example of a chisel:
Tangent alert – This image is shown as an example of how edge failure occurs in the very last few thousandths. If you can eliminate failure there, you can pretty much eliminate it entirely. Coincidentally, the V11 chisel in a test was one of only two that couldn’t cease showing damage even with the buffer. I didn’t care for the chisel and it was easy to get rid of. Other chisels that cost less than half as much held up better to the point that I’d recommend against a serious chisel user buying any chisel made of V11. To be fair, the A2 used in IBC and LN chisels isn’t anything special, either – increasing edge fracture tendencies by adding carbides for wear resistance is kind of a dippy thing. Chisels fail by impact, not by wear, and plain inexpensive steels without much carbide volume do better as chisels than anything heavily alloyed. Even the Japanese matrix chisels that are driven to high hardness may use alloying, but the matrix steels are chosen because they don’t allow carbides of any size to form. Carbides improve wear, but they are nearly always where edge fracture starts – the carbides crack and then the crack travels out into the matrix of the steel. To pay a high cost for this privilege is strange and older superior chisels like Ward & Payne have almost no visible carbides when the matrix is abraded. A good quality older Ward chisel or something else of good hardness will cost less, sharpen faster and chisel longer than any of the air hardening steels that really are there, in my opinion, to make heat treatment easier for manufacturers. It’s not a surprise when an inexpensive used Japanese chisel off of Japan’s auction site leaves V11 or A2 in the dust. CTS-XHP (probably identical to V11) does make a wonderful semi-stainless abrasion resistant slicing knife, though. It’s not without merit – it’s just senseless expense in chisels.
This image was part of testing the method, but it’s typical work. Chopping maple or cherry both result in what you see. The damage against the line is enough to increase the effort to use the tool, but notice that no matter how much edge length you take a picture of, the depth doesn’t get much worse than shown with the 30 degree edge. It’s about 2 thousandths deep.
So, if that’s the case, why would we spend time talking about how much bevel strength we need 1/8th up the length of a chisel, and why would we get stuck in Sellers-esque nonsense about convex bevels. In fact, the idea of convexity othr than at the last several thousandths of the tip is extremely counterproductive and the older texts (when productivity mattered) go well out of their way to describe not allowing any convexity in the grind itself. I found these this year, so they didn’t really direct hashing this out – I came upon the method by accident in exasperation using an incannel patternmaking gouge in siliceous wood. Buffing the tip and grinding the angle thin suddenly made a far easier to push gouge and the edge didn’t dent – not even from silica. It was a shock.
Reading older texts and seeing their descriptions about grinding at a shallower angle and then honing the tip is just icing on the cake after the fact.
Controlling where Failure Occurs
At the same time, I recalled Cliff Stamp talking in a knife video – something I don’t watch much of, but he said something along the lines of adjusting bevels and apexes of edges to determine where the failure point would be. This had some ring to it once I looked at straight razor edges and found them to work better after the strop had adjusted the very tip. You can shave with a straight razor for a year if you hone and strop it properly, stropping daily and perhaps using the linen weekly. It will appear to take almost no wear, not even under a metallurgical scope. If you don’t use the linen and leather properly, the edge will dent, and you’ll be back to the stones.
This leads to the same thing with an edge – if the edge is typically damaged in the first few thousandths of an inch before you find it totally intolerable, then why address the problem with a whole bunch of other edge real estate that isn’t the problem. That doesn’t make sense. The lucky find with the incannel gouge was just an attempt to be able to power grind the bevel and then “round over” the tip with a buffer without allowing the tip to be too blunt.
There’s nothing that original about this thought in terms of history, but it was original locally to me – like in my shop. After finding an edge of a gouge literally taking scratches on the back and not denting at the edge, it seemed natural to think about what Cliff said and drop the angle of the grind and hone behind it until it fails. I didn’t chase this failure at first, but rather just honed the bevel shallower by feel so that chisels would slip through wood paring and malleting more easily.
You’d be shocked how much longer a chisel edge will last and through things you’d think you can’t chisel – if you just prevent the initiation of damage at the very apex in the first place. Just as I was shocked how much easier it was to use a patternmaker’s gouge to hog off end grain on a cabinet once the edge stopped deflecting.
I did eventually find failure of the bevel, though – as per Cliff’s comments – if the bevel gets much below 20 degrees, you’ll soon find it too weak to prevent the edge itself from being folded back into the bevel. So I ended up landing by feel at 20 degrees. Not by prescription, and I never took a picture of the bevel profile of the edge until someone I respect on a forum requested I do it. In the world of outcomes, sometimes you only need to compare feels and you don’t need to see pictures. This method never needed the microscope to determine angles, and I think you shouldn’t get tied up in trying to be too precise with it, either.
Of Making by Hand with Wood and Steel 