Steel that performs better when polished, and holds razor sharpness

Twindog said:
Rex 121 at 70 Rc, for sure.

In Larrin's data, ZDP 189 at 65 Rc gets 720 TCC.

Rex 121 at 71 Rc gets 1,010 TCC
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DISCLAIMER: I havent comprehensively read all of Larrin's stuff..
But in general I think Larrin's data is more scientific, as to remove as much variability. Although it is a good baseline, more scientific and the most efficient and logical way to test they are incomplete, but its the best resource we have atm.
What if there exist conditions that will have an affect on the results if changed. You can only expect the results from larrins data if your blade also satisfies the same variables of his. Theres no way to tell from larrin stuff that if some variables were changed how each steel will then preform. For example if all the steels were highly polished, then s90v/s110v will actually do worse and zdp would preform better.

I want to know what is the max performance that can be squeezed out of a particular steel if given the ideal conditions. To do a test like this you would have to test each steel individually for a range of variables and then compare the results to each other steel, this would be more comprehensive, and exponential amount of work.
 
Larrin said:
It is always humorous to me that people can say if a variable in a test was changed it would then fit their preconceived ideas.
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I was referring more to testing a larger range of variables per steel as opposed to the other way around.
Ex. what is the max tcc of a given steel, given this range of variables

Edit.. But as i mentioned this is exponentially more work
 
I've tried maxamet, 10v, k390, s125v but I don't polish edges as I prefer coarser edges. I sometimes deburr on 6K diamond stone or 0.1 diamond loaded leather strop for kitchen knives, but I don't polish, so can't help in that respect. To me polished edges are not very useful, but to each his own. Maybe someone that knows this stuff better like Larrin Larrin or DeadboxHero DeadboxHero can chime in. I don't see a mechanism that would explain how a more fine grained, with smaller carbides, more wear resistant steel when polished would be inferior to the steel that has larger, softer carbides. If we assume that wear resistance is why the edge fails and that you abrade both types of carbides then the more wear resistant steel with smaller carbides should still be superior. Maybe carbide volume has something to do with it, but I don't know why it would matter for this specifically. Since you are using different knives with different geometries I am wondering if what you are experiencing is due to geometry or sharpening and not the type of steel itself. I've seen experiments and studies that showed that in general for many steels coarser edges last longer than polished edges, so for example 400-600 grit edge is superior to 1200-2000 grit as far as longevity is concerned.

This article touches on the grid of the edge a little https://knifesteelnerds.com/2018/06/18/maximizing-edge-retention/
 
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shinyshinyblades said:
I love a smooth push cut that feels like a laser, which you only get when you bring a blade to an extremely high polish.
I also love for a blade to retain its hair whittling razor sharpness as long as possible. I dont care how long a working or toothy edge will last.

Unfortunately most of the test and demos ive seen don't really test how long hair whittling razor sharpness is maintained.

Can anyone recommend blade steels that have these characteristics, and maybe steels I should avoid?

The only steel that i own that comes close to this description is ZDP 189 which when highly polished gives me an almost 30-40% increase in edge retention.
It also seems to keep that hair whittling razor sharpness for a much longer period than my other blades (s30V,m390)
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I did some edge retention tests on around 15-20 types of steel, the test only took absolute sharpness not working edge results.
I cut into and dragged the edge over a very hard polymer surface, until the blade would no longer cleanly cut through tissue paper (Not printer paper)
I found that certain steels stopped cutting the tissue after only 1-2 cuts into the polymer. Other steels lasted longer, steels liks S30V / S35VN all did around 4-5 cuts. K390 did around 8. CTS-XHP from spyderco did around 17. Some M2 tool steel HT to 65 HRC did the highest at around 18-19 cuts before it lost it's bsolute edge and no longer cleanly sliced through tissue paper.
I test some companies S30V against each other. Like Spyderco and Benchmade and found very little if any difference. Both scoring around 4-5.
Surprisingly Sandviks 12C27 which is a razor steel, scored quite low. I tested Opinels, Spydercos and others. They all scored around 1-3 cuts.
14C28N seemed to do better, scoring a 3-4 on average, not far off S30V.
Hogues Cryo Treated 154CM did better than expected, holding up with S30V at 4-5 cuts.
I noticed that HRC played a big factor. When I tested some D2 the softer D2 from Ontario only scored a 3, while some harder D2 scored a 4-5.
I even tested some very hard 1095 from a knife with a hamon, with an edge over 64 HRC, and that scored a 7, which was better than some of the higher alloyed knife steels with lower HRC.
When Hultafors AUS 8 was tested it could not even do 1 cut without losing it's absolute sharpness.
I recorded all of the tests, if you look around you can find them online.
 
Londinium Armoury said:
I did some edge retention tests on around 15-20 types of steel, the test only took absolute sharpness not working edge results.
I cut into and dragged the edge over a very hard polymer surface, until the blade would no longer cleanly cut through tissue paper (Not printer paper)
I found that certain steels stopped cutting the tissue after only 1-2 cuts into the polymer. Other steels lasted longer, steels liks S30V / S35VN all did around 4-5 cuts. K390 did around 8. CTS-XHP from spyderco did around 17. Some M2 tool steel HT to 65 HRC did the highest at around 18-19 cuts before it lost it's bsolute edge and no longer cleanly sliced through tissue paper.
I test some companies S30V against each other. Like Spyderco and Benchmade and found very little if any difference. Both scoring around 4-5.
Surprisingly Sandviks 12C27 which is a razor steel, scored quite low. I tested Opinels, Spydercos and others. They all scored around 1-3 cuts.
14C28N seemed to do better, scoring a 3-4 on average, not far off S30V.
Hogues Cryo Treated 154CM did better than expected, holding up with S30V at 4-5 cuts.
I noticed that HRC played a big factor. When I tested some D2 the softer D2 from Ontario only scored a 3, while some harder D2 scored a 4-5.
I even tested some very hard 1095 from a knife with a hamon, with an edge over 64 HRC, and that scored a 7, which was better than some of the higher alloyed knife steels with lower HRC.
When Hultafors AUS 8 was tested it could not even do 1 cut without losing it's absolute sharpness.
I recorded all of the tests, if you look around you can find them online.
Click to expand...
this is pure gold and the type of stuff im looking for.
i would have thought that k390 would do better than CTS-XHP for something like this?
I guess theres another reason why i love the chaparral so much

what kind of polymer surface was this? let me know, I'm willing to test this on my zdp when I get the chance
 
CTS-XHP will not have the wear resistance of K390 -- it's more in the D2 range. Scroll down to the bottom of this spec sheet from Alpha Knife Supply.
CTSXHP-DS.pdf

Rex 121 will be much, much better for wear resistance.

You don't seem to want to hear this for some reason and don't want to accept Larrin's well respected work. But you can Google around and see the tests that people have done with this amazing steel. It easily beats Maxamet for wear resistance. As an alloy, It has 10 percent tungsten and 9.5 percent vanadium. Not too tough, but as hard as you're going to get with steel, and killer wear resistance.

Get someone to make you a very thin blade of Rex 121 with acute geometry. If you have the skills to put on a killer edge with no burr, it will cut forever if you don't abuse it.
 
shinyshinyblades said:
this is pure gold and the type of stuff im looking for.
i would have thought that k390 would do better than CTS-XHP for something like this?
I guess theres another reason why i love the chaparral so much

what kind of polymer surface was this? let me know, I'm willing to test this on my zdp when I get the chance
Click to expand...
I thought the K390 would out perform the XHP as well. There's always a chance the XHP was higher HRC batch than normal, or the K390 was a lower HRC batch (Both from Spyderco) The geometry were similar (Delica Vs Chaparrel geometry)
I did it on a type of kitchen floor tile, a PVC Vinyl compound one. You can pick them up cheap online companies even offer free samples. I held it on a table edge and applied around 30-40 lbs of pressure while drawing the edge over the tile.
 
Twindog said:
CTS-XHP will not have the wear resistance of K390 -- it's more in the D2 range. Scroll down to the bottom of this spec sheet from Alpha Knife Supply.
CTSXHP-DS.pdf

Rex 121 will be much, much better for wear resistance.

You don't seem to want to hear this for some reason and don't want to accept Larrin's well respected work. But you can Google around and see the tests that people have done with this amazing steel. It easily beats Maxamet for wear resistance. As an alloy, It has 10 percent tungsten and 9.5 percent vanadium. Not too tough, but as hard as you're going to get with steel, and killer wear resistance.

Get someone to make you a very thin blade of Rex 121 with acute geometry. If you have the skills to put on a killer edge with no burr, it will cut forever if you don't abuse it.
Click to expand...

The wear resistance of the larger carbides do not come into contact with the absolute apex of the knife edge. the absolute apex is not big enough to house a large carbide. This is why we see high wear steels kick in more and continue cutting when a working edge is toothy. The data I collected through my tests shows that when testing the absolute sharpness of the apex, some steels with far greater wear resistance do not keep their absolute hair whittling edge longer than some steels with lower wear capability.

I tested the CTS XHP against the K390 over 6 times and got the same result every single time, the K390 on the Delica lost it's absolute sharpness before the Chaparrel in XHP. The M2 tool steel running at 65 HRC also out performed it by almost double.

 
Londinium Armoury said:
The wear resistance of the larger carbides do not come into contact with the absolute apex of the knife edge. the absolute apex is not big enough to house a large carbide. This is why we see high wear steels kick in more and continue cutting when a working edge is toothy. The data I collected through my tests shows that when testing the absolute sharpness of the apex, some steels with far greater wear resistance do not keep their absolute hair whittling edge longer than some steels with lower wear capability.

I tested the CTS XHP against the K390 over 6 times and got the same result every single time, the K390 on the Delica lost it's absolute sharpness before the Chaparrel in XHP. The M2 tool steel running at 65 HRC also out performed it by almost double.

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Your testing is interesting. First, I said that all steels will lose their initial high-sharpness very fast.

Second, so much depends on the sharpening technique and skill that created the edge.

Sharpened carbides can exist within the apex if they are sharpened with very fine diamonds at a high grit -- provided you don't tear out the carbides before you get to the high-grit stones.

There is no reason why the apex geometry of a high-wear steel has to be any different than that of a low-wear steel. If the apex geometry is the same, the high-wear steel will hold a super keen edge longer than a low-wear steel, but both will dull fast from that highest level of sharpness.

My Rex 121, with a thin blade and a hardness of 70 Rc, holds a very sharp edge (not just a working edge) for a long, long time. No other knife I have comes even close.
 
Londinium Armoury said:
The wear resistance of the larger carbides do not come into contact with the absolute apex of the knife edge. the absolute apex is not big enough to house a large carbide. This is why we see high wear steels kick in more and continue cutting when a working edge is toothy. The data I collected through my tests shows that when testing the absolute sharpness of the apex, some steels with far greater wear resistance do not keep their absolute hair whittling edge longer than some steels with lower wear capability.

I tested the CTS XHP against the K390 over 6 times and got the same result every single time, the K390 on the Delica lost it's absolute sharpness before the Chaparrel in XHP. The M2 tool steel running at 65 HRC also out performed it by almost double.

Click to expand...
The M2 results don't surprise me. I have one at a reported 66.5 and it keeps a keen edge very well. About the only thing I have that rivals it is zdp89 and maxamet. It's probably no coincidence they are all 65+ hrc.
I have several lower hardness M2 benchmades that are no slouches. They actually do better than run of the mill M4.

All of this of course flies in the face of published data and tests I've read. oh well....
 
jpm2 said:
The M2 results don't surprise me. I have one at a reported 66.5 and it keeps a keen edge very well. About the only thing I have that rivals it is zdp89 and maxamet. It's probably no coincidence they are all 65+ hrc.
I have several lower hardness M2 benchmades that are no slouches. They actually do better than run of the mill M4.

All of this of course flies in the face of published data and tests I've read. oh well....
Click to expand...

I know, it does appear to, but it might have something to do with the exact level of sharpness reduction being measured. After all of my tests each blade could still shave hair. So saying any dulled is not accurate, but it measured the highest level of sharpness I could manage. A knife needs to be very sharp to cleanly slice tissue paper. I'm not sure how to measure it to minimize loss. Maybe going from 50 bess to 40 bess? it's such a small amount, from being able to slice tissue, to being able to only shave hair, but no longer able to slice tissue.
I think the HRC matters more than the chemical composition (to an extent) when measuring only the very apex and absolute sharpness loss, all of the high HRC blades did well because maybe edge stability more than edge wear was being looked at.
 
Just wanted to say I'm not disputing any of Larrins finding's or data on NSN. I'm just explaining my testing and trying to guess why the numbers were what they were. All I can think of was HRC, and the absolute apex having more to do with stability rather than wear resistance, because the absolute apex before it reaches carbides, is possibly more effected by only the hardness of the steel, rather than the carbides which sit just below the apex.
 
Londinium Armoury said:
I thought the K390 would out perform the XHP as well. There's always a chance the XHP was higher HRC batch than normal, or the K390 was a lower HRC batch (Both from Spyderco) The geometry were similar (Delica Vs Chaparrel geometry)
I did it on a type of kitchen floor tile, a PVC Vinyl compound one. You can pick them up cheap online companies even offer free samples. I held it on a table edge and applied around 30-40 lbs of pressure while drawing the edge over the tile.
Click to expand...

Vinyl composition tile (VCT)? It's 12" square and usually 1/8" thick (at least in the US)?

51941
 
YXR7 is the other steel Rockstead uses aside from ZDP-189 and is always polished to mirror like keeness!!
Not sure how available it is other than their knives, but it might suit your needs
 
JR42 said:
Vinyl composition tile (VCT)? It's 12" square and usually 1/8" thick (at least in the US)?

51941
Click to expand...
They are just a Vinyl composite, they come in many different grades, I have no clue which exact grade they are. But it's just similar to Micarta or a resin based fiber type structure. It's pretty similar in feel to cutting into micarta when making batches.
 
My best results have been (in no particular order) Hitachi White from Murray Carter and M2 HSS at 66 HRC. The M2 I expected, the White surprised me. I have a Murray Carter that I open all my mail with, I haven't sharpened it in over a year. When the edge starts to drag, I touch it up.
 
Stick with steel designed for a knife, tool steel is engineered for toothy high speed cutting imho , M4 , zdp seems to hold that polished edge well
 
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