Which steel at what HRC holds the longest razor fine edge?

L

Londinium Armoury

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Jun 2, 2020
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I would like this to be a collection of data testing results and user experience with discussion and comparisons. To find the optimal steel composition at the optimal hardness, and optimal edge angle to produce the longest lasting fine edge.
I would like to avoid discussing working edges in this thread as the main topic (Bring them up for comparisons but don't focus on them please)
If I were searching for the worlds best as of 2021 in the ability to hold a fine shaving sharp edge, what steel at what HRC would we be talking about? (eg Shirogami, 65 HRC, 10 dps)

I feel everybody these days is always doing tests and talking about working edge of high wear steels, thats great and all and I love me a bit of Vanadium in my folders like every other cardboard cutting enthusiast.
What about absolute ability to hold the worlds longest fine edge? I'm the type of person who thinks his knife is dull if it fails the 3 finger test, and doesn't instantly feel the blade cutting into the first layer of skin upon a tiny soft drag. Or if my knife cant cut through paper towel I think it's time to hit the ceramic rods for a few passes.
What is the ultimate top tier list for fine edge holding, top 5, top 10, data samples from 50? Anything and everything is welcome.
How long did something last while just shaving hair, how long did something last while cutting abrasive material while still being shaving sharp. There's lots of different variables and I want to know them all. User experience is also highly welcome even if you dont have testing data recorded. Say you got a custom from a local smith who did a particular knife for you at some ridiculously high HRC and you noticed the grain was especially fine and could shave a mosquitos back hair for 3 years, I'd like to know that too.
Cheers.
 
WValtakis said:
I've always been very impressed with ZDP-189 at about 67hrc.
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I will get around to picking up an Endura or Delica in ZDP very soon. I thought they were forever production models, but I saw on the American blade stores "Discontinued" marked above the listings, which made me think okay time to grab one before they all go. That's one steel I don't have much experience with, I've heard very good things though. Better go grab a ZDP Endura before they all go.
 
Assuming you got one that arrived razor sharp, nothing is going to beat a Sandrin Torino or Lanzo. (If you got a blunt one - which is unlikely - you'd be in trouble because they're almost impossible to sharpen.)
Of course, these blades, being tungsten carbide, aren't steel as such, but they are extremely sharp and durable blades, which I think qualifies them for discussion. 71 HCR! I hope to get one soon so I should one day be able to speak from experience!
 
As you test lower and lower amounts of sharpness loss the scatter in the test becomes greater because it becomes more reliant on the initial sharpening. There was a guy on YouTube doing BESS tests after minor cutting tests like slicing paper and it was surprising how much variation there could be.
 
Oh yeah, I have been meaning to get a ZDP something for a while now. Always fancied the Stretch but it was (and still is) really expensive vs the Endura for some reason!
 
There's always William Henry or Rockstead if you can't find a ZDP-189 Spyderco you like;)
 
Thunderpants said:
Oh yeah, I have been meaning to get a ZDP something for a while now. Always fancied the Stretch but it was (and still is) really expensive vs the Endura for some reason!
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Not to derail my own thread but I have no idea why the stretch is like double the price of the endura, maybe because it's not as popular and doesn't sell as many units. I noticed my UKPK is basically a slip joint version of the stretch.
 
Thunderpants said:
Assuming you got one that arrived razor sharp, nothing is going to beat a Sandrin Torino or Lanzo. (If you got a blunt one - which is unlikely - you'd be in trouble because they're almost impossible to sharpen.)
Of course, these blades, being tungsten carbide, aren't steel as such, but they are extremely sharp and durable blades, which I think qualifies them for discussion. 71 HCR! I hope to get one soon so I should one day be able to speak from experience!
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I know a few people who own them and are very impressed. I don't see why we should exclude carbide alloys from the list, in fact it would be interesting to see how good they do at taking and holding a fine edge, or if they are even capable of taking an edge as refined at some of the finer grain steels. I think you could sharpen them on diamond stones, probably don't want to go too low on the grit though in case you cause chipping issues, maybe start on a 600 grit diamond stone, then take your time.
 
Larrin said:
As you test lower and lower amounts of sharpness loss the scatter in the test becomes greater because it becomes more reliant on the initial sharpening. There was a guy on YouTube doing BESS tests after minor cutting tests like slicing paper and it was surprising how much variation there could be.
Click to expand...

This is very interesting to me. I thought it would be fun to test H1 v LC200N using cardboard for the cutting material and weighted string cutting for the test. Although the test appeared to be statistically consistent ( I did trials of just cutting string of 50 and 100 to test for consistency) the actual data produced as I cut cardboard was bizarre. I did a series of tests and then stopped because I was either producing bad data or did not understand enough to know what I was seeing was "correct". The graphs ended up looking like this, I measured every 12 inches of cardboard cut and each string cutting was the average of 5 cuts. The edges were all at 15° with ZDP189 at 12.5°.

c1.png


I've since read a ton of articles and posts from both yourself and Cliff Stamp that leads me to believe although I may not be producing bad data, it's certainly not as robust as it should be. I suspect I am not consistent enough with my sharpening style, in addition to other factors.

OP, one of the main things I discovered in my testing was that regardless of data produced, H1 with an 7.5° edge was extremely close to ZDP189 with a 12.5° edge. They were both cutting, shaving, and grabbing that first little layer of skin, very close for the first 60 feet or so of cardboard I cut. I am not entirely convinced of these results. So personally, I would pick ZDP189 because I've used and sharpened it a ton and although I haven't tried many of the current crop of super steels it performs very well for me. Generally, if I can't cleanly filet a errant piece of cuticle skin I get irritated and need to hone the edge.

c2.png
 
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Larrin said:
As you test lower and lower amounts of sharpness loss the scatter in the test becomes greater because it becomes more reliant on the initial sharpening. There was a guy on YouTube doing BESS tests after minor cutting tests like slicing paper and it was surprising how much variation there could be.
Click to expand...

Do you happen to have any test data purely on fine edge holding? if you could link to some results I'd like to see the numbers.
 
spoonrobot said:
This is very interesting to me. I thought it would be fun to test H1 v LC200N using cardboard for the cutting material and weighted string cutting for the test. Although the test appeared to be statistically consistent ( I did trials of just cutting string of 50 and 100 to test for consistency) the actual data produced as I cut cardboard was bizarre. I did a series of tests and then stopped because I was either producing bad data or did not understand enough to know what I was seeing was "correct". The graphs ended up looking like this, I measured every 12 inches of cardboard cut and each string cutting was the average of 5 cuts. The edges were all at 15° with ZDP189 at 12.5°.

c1.png


I've since read a ton of articles and posts from both yourself and Cliff Stamp that leads me to believe although I may not be producing bad data, it's certainly not as robust as it should be. I suspect I am not consistent enough with my sharpening style, in addition to other factors.

OP, one of the main things I discovered in my testing was that regardless of data produced, H1 with an 7.5° edge was extremely close to ZDP189 with a 12.5° edge. They were both cutting, shaving, and grabbing that first little layer of skin, very close for the first 60 feet or so of cardboard I cut. Personally, I would pick ZDP189 because I've used and sharpened it a ton and although I haven't tried many of the current crop of super steels it performs very well for me.
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I'm surprised H1 can even maintain a working apex at 7.5 dps, was it production spyderco or some work hardened piece?
I don't even know what to make of your graphs, why is H1 jumping all over the place like that, is it lost and in need of a map, haha.
Nice testing though, even if I don't quite understand the results.
 
spoonrobot said:
I've since read a ton of articles and posts from both yourself and Cliff Stamp that leads me to believe although I may not be producing bad data, it's certainly not as robust as it should be. I suspect I am not consistent enough with my sharpening style, in addition to other factors.
Click to expand...
All testing has scatter and nothing ever looks perfect. I would recommend testing on a “log scale” meaning you test sharpness more at initial stages and then less often with more cutting. For example, test sharpness after 1 inch of cardboard, then 3 inches, 10, 30, 100, 300, 1000, etc. Initial blunting is faster and as you cut more the changes occur more slowly. But having scatter does not invalidate testing. No matter what the trolls and uninformed have to say about it.
 
Larrin said:
I did analysis of sharpness loss in the first cut of a CATRA test against the full test here: https://knifesteelnerds.com/2018/11/26/steel-edge-retention2/
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I'm about halfway through the article and I have a question. With the high wear steels losing their fine edge on the first stroke, you mention a 1 micron edge can't contain a 5 micron carbide. So if the carbides are not very fine then anything in the initial apex wont actually contain any of the 5 micron carbides at all, then the edge will stabilize itself at the 5 micron size carbides and form a thicker apex right? which will then be a working edge and continue cutting like that.
If I read that correctly is it safe to assume you want carbides as small as 1 micron to form the actual apex in order to hold that initial fine edge for long periods? Or in other words if your knife contains average micron size of 4, you shouldnt even bother trying to put a 1 micron edge on it to begin with because that is just going to wear away very fast because the actual apex doesn't even contain any carbides because it's simply too small to house the larger carbides.
 
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