I Tested the Edge Retention of 48 Steels

Monofletch said:
I have found my Magnacut edge bevel rusting in the high humidity of the Midwest. After removing that initial discoloration with a strop and diamond paste I have had NO more issues with rust or discoloration.
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Possibly contamination or overheating from grinding, should only affect the outer layer of the steel.
 
Dear mr. Larrin Thomas,
At the time you created your reports, everybody is referring to these days when it comes to comparing knive steels ( thank you for your work) , did you consider 15V as made with the Shawn Houston heat treatment and used by Spyderco or did you use a “Non Big Brown Bear” 15V version of the steel? I do note , forgive me when I am wrong, that the hardness of the 15V in your presentation is below the approx 65 rc Spyderco is using in their applications of 15V.

In case you did not consider the BBB heat treated version of 15V in your evaluations, what consequences would it have if you would do so? I mean what notes would be applicable for toughness , edge retention & corrsion resistance? ( currently in your stats: 3.5, 10, 4)
 
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kasumi said:
Dear mr. Larrin Thomas,
At the time you created your reports, everybody is referring to these days when it comes to comparing knive steels ( thank you for your work) , did you consider 15V as made with the Shawn Houston heat treatment and used by Spyderco or did you use a “Non Big Brown Bear” 15V version of the steel? I do note , forgive me when I am wrong, that the hardness of the 15V in your presentation is below the approx 65 rc Spyderco is using in their applications of 15V.

In case you did not consider the BBB heat treated version of 15V in your evaluations, what consequences would it have if you would do so? I mean what notes would be applicable for toughness , edge retention & corrsion resistance? ( currently in your stats: 3.5, 10, 4)
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There is only one version of the steel. It can be heat treated to different hardness levels. The ratings are normalized to a consistent hardness apart from a few exceptions where steels are only used in a certain range. So the ratings would not change.
 
Larrin said:
There is only one version of the steel. It can be heat treated to different hardness levels. The ratings are normalized to a consistent hardness apart from a few exceptions where steels are only used in a certain range. So the ratings would not change.
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Thanks for the fast reply Larrin. I thought that Shawn Houston had done quite some more “hocus pocus” with his heat treatment than just up the hardness and that with his specific way of heat treating the properties would have gotten an “update” vs your non Spyderco BBB treated 15V test results. ( at least I assume that your test material was not Shawn’s as you indicate lower hardness in your publications).
Best regards from The Netherlands!
 
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kasumi said:
Thanks for the fast reply Larrin. I thought that Shawn Houston had done quite some more “hocus pocus” with his heat treatment than just up the hardness and that with his specific way of heat treating the properties would have gotten an “update” vs your non BBB treated 15V test results. ( at least I assume that your test material was not Shawn’s as you indicate lower hardness in your publications).
Best regards from The Netherlands!
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I think you are confusing my ratings with what is necessary to make a good industry-level heat treatment. They are two different things. My ratings for 15V are very high. Without someone like Shawn putting in the real work to develop an excellent heat treatment, it likely would be significantly worse than my ratings. Achieving a high hardness level is challenging to begin with, and industry heat treaters often do it poorly with bad toughness and sharpenability. The datasheet doesn’t show that it can reach 65 Rc. You have to know what you are doing to develop that.
 
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Larrin said:
I think you are confusing my ratings with what is necessary to make a good industry-level heat treatment. They are two different things. My ratings for 15V are very high. Without someone like Shawn putting in the real work to develop an excellent heat treatment, it likely would be significantly worse than my ratings. Achieving a high hardness level is challenging to begin with, and industry heat treaters often do it poorly with bad toughness and sharpenability. The datasheet doesn’t show that it can reach 65 Rc. You have to know what you are doing to develop that.
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Thanks again. Sorry for any of my confusion but I still do not get exactly what I am after.( probably due to not being native English speaker / writer)
What I understand from what I read about heat treating blades will the properties in a given blade with given geometry change with the change of the hardness in 100% comparable/same blade. In all 3 aspects that you have rated knifesteels in. Now I do see in your statistics that you put 15V in there at a hardness of about 63 I believe it is. BBB Spyderco blades are at 65 rc , so my assumption is that your blade you used for getting your results at 63 rc will give different results at 65 rc. In edge retention, toughness and corrosion resistance. So if you have tested with non Spyderco BBB treated knifeblade at 65 rc but a 15 V blade at 63 rc ,as is the case according to my perception , I expect different ratings.
You say : “Without someone like Shawn putting in the real work to develop an excellent heat treatment, it likely would be significantly worse than my ratings.”. So this suggest to me that you used Shawn’s heat treated 15V but then the question is why not at 65rc as it was brought to the market and what effect would this 2 rc higher have on the ratings for toughness, edge retention and corrosion resistance.
 
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By the way Dr. Larrin , “whilst I have you on the phone 😉“…..
Do you expect your final MagnaMax blade as you envision it ( I know final phase at producers is not finished as far as you communicated) to have equal, better or worse edge retention and edge stability when compared to a 15V blade with both blades the same geometry of let’s say a spyderco Native 5 at 15 dps?

I know that it will surpass 15V in toughness and corrosion resistance but answers to my question above would for me be more relevant in my personal choice.
 
kasumi said:
Thanks again. Sorry for any of my confusion but I still do not get exactly what I am after.( probably due to not being native English speaker / writer)
What I understand from what I read about heat treating blades will the properties in a given blade with given geometry change with the change of the hardness in 100% comparable/same blade. In all 3 aspects that you have rated knifesteels in. Now I do see in your statistics that you put 15V in there at a hardness of about 63 I believe it is.
BBB blades are at 65 rc , so my assumption is that your blade you used for getting your results at 63 rc will give different results at 65 rc. In edge retention, toughness and corrosion resistance. So if you have tested with non BBB treated knifeblade at 65 rc but a 15 V blade at 63 rc ,as is the case according to my perception , I expect different ratings.
You say : “Without someone like Shawn putting in the real work to develop an excellent heat treatment, it likely would be significantly worse than my ratings.”. So this suggest to me that you used Shawn’s heat treated 15V but then the question is why not at 65rc as it was brought to the market.
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No, the BBB heat treatment is a proprietary heat treatment developed by me and put into production by Spyderco.

All the main CATRA testing was done before the release of the BBB Spyderco 15V.

So, to argue that the hardness doesn't match what is available on the market is ignoring the timeline of events and the objective for the CATRA testing to normalize the hardness in the range of 62-63 with some exceptions.

Spyderco did internal testing in their lab with CATRA testing which showed improvement over the standard heat treatment. Unfortunately that is not publicly available information.



We have also seen great reports in real world testing over the years so it's not just HRC and the BBB 15V is quite proven now.

Should the steel ratings reflect this? I don't think it needs to, it is a steel rating not a knife rating.

While steel is not separate from the heat treatment, geometry and even the sharpening the work done by Knife Steel Nerds is absolutely crucial to understanding how things work thanks to isolating things so that we can see how they compare and it should never be taken for granted.


I was at Golden Colorado just few weeks ago, here's what Sal had to say about it when I was in the Spyderco lab.


I know that everybody always wants to solve the mystery of how things work. However, you don't need to know how a watch works to tell time and If you have any thoughts about trying some BBB 15V time is running out. Crucible Industries LLC is gone and it will not make the transition to Erasteel.
 
Shawn says:

“No, the BBB heat treatment is a proprietary heat treatment developed by me and put into production by Spyderco.
All the main CATRA testing was done before the release of the BBB Spyderco 15V.”

That is exactly my point. As nearly all knives ever made and sold with 15V are with the Spyderco heat treat at 65rc from you it would be better in my opinion , for all those people who check “their” choice of knives with he Dr. Larrin files , to have your 65rc heat treated 15V as a reference for the ratings . If that does not make a difference in the ratings for toughness , corrosion resistance and edge retention what is the value of your magic work on the 15V heat treat then?

If I want to check if 15V fits my needs in a knife and I am a serious person I would check dr. larrins ratings on the steel I have in mind. At the same time if I want to buy a knife in 15V I have 99.9% chance it will be a Spyderco knife . So those 2 matching is not a bad idea according to my thinking. When people check the dr Larrin files for properties on the 15V I learnt today that there is no difference in properties between “pre BBB 15V heat treat development” and after “BBB 15V heat treat development” exept an increase in hardness. Quote dr. Larrin: “There is only one version of the steel. It can be heat treated to different hardness levels”. I really thought that there was more “special” from the BBB heat treat than only slight increased rc in my 2 15V Spyderco knives. Nevertheless I still don’t understand that the ratings on all 3 points from pre Spyderco BBB released 15V metal and after BBB heat treatment 15V metal , making up for a 2 hrc difference, do not change.
…. Maybe even a bit disappointed 😔 although I am super happy with the knives. )
 
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Shawn says:”
I know that everybody always wants to solve the mystery of how things work. However, you don't need to know how a watch works to tell time and If you have any thoughts about trying some BBB 15V time is running out. Crucible Industries LLC is gone and it will not make the transition to Erasteel.”

I do not have the slightest interest how things work by the way….Don’t know why you make this remark / suggestion in reaction to my post.

And also your remark: “ the work done by Knife Steel Nerds is absolutely crucial to understanding how things work thanks to isolating things so that we can see how they compare and it should never be taken for granted” suggests in a way that I would doubt the value and importance of his work. Which is absolutely not the case . On the contrary. Also here I don’t see the relevance in response of my post.

From your reply I get the feeling I offended anyone or touch on inappropriate issues….. never my intention.
 
kasumi said:
Shawn says:

“No, the BBB heat treatment is a proprietary heat treatment developed by me and put into production by Spyderco.
All the main CATRA testing was done before the release of the BBB Spyderco 15V.”

That is exactly my point. As nearly all knives ever made and sold with 15V are with the heat treat from you it would be better in my opinion , for all those people who check “their” choice of knives with he Dr. Larrin files , to have your heat treated 15V as a reference for the ratings . If that does not make a difference in the ratings for toughness , corrosion resistance and edge retention what is the value of your magic work on the 15V heat treat then?

If I want to check if 15V fits my needs in a knife and I am a serious person I would check dr. larrins ratings on the steel I have in mind. At the same time if I want to buy a knife in 15V I have 99.9% chance it will be a Spyderco knife . So those 2 matching is not a bad idea according to my thinking. When people check the dr Larrin files for properties on the 15V I learnt today that there is no difference in properties between “pre BBB 15V heat treat development” and after “BBB 15V heat treat development” exept a slight increase in hardness. Quote dr. Larrin: “There is only one version of the steel. It can be heat treated to different hardness levels”. I really thought that there was more “special” from the BBB heat treat than only slight increased rc in my 2 15V Spyderco knives. Nevertheless it is of course you say although I still don’t understand that the ratings on all 3 points from pre BBB and after BBB heat treatment do not change from the BBB heat treatment. (Haha…. Maybe even a bit disappointed 😔 although I am super happy with the knives. )
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Well, there is something more "special" than just an HRC increase.

However, I am not at the liberty to discuss proprietary details.

If you need proprietary knowledge to enjoy the product then my apologies.

If you make the knives yourself, that may also give you a higher locus of control for the desire you seek.

For some people, understanding how the watch works is more exciting than using and enjoying the watch.

However, it gets to a certain point where if you want the highest level of enjoyment from understanding you need to make the watch yourself.
 
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kasumi said:
Shawn says:”
I know that everybody always wants to solve the mystery of how things work. However, you don't need to know how a watch works to tell time and If you have any thoughts about trying some BBB 15V time is running out. Crucible Industries LLC is gone and it will not make the transition to Erasteel.”


I do not have the slightest interest how things work by the way….Don’t know why you make this remark / suggestion in reaction to my post.
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You asked for leniency for not being a native English speaker, I ask you for the same in return. It was not my intention for a negative context on that.

I was assuming we are like-minded. I want to know how things work also which is what leads me to make things.




kasumi said:
And also your remark: “ the work done by Knife Steel Nerds is absolutely crucial to understanding how things work thanks to isolating things so that we can see how they compare and it should never be taken for granted” suggests in a way that I would doubt the value and importance of his work. Which is absolutely not the case . On the contrary. Also here I don’t see the relevance in response of my post.

From your reply I get the feeling I offended anyone or touch on inappropriate issues….. never my intention.
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Yes, well we are not having a private conversation. We are having a public discussion, so the audience is everybody that reads even people that read this 10 years from now. So I have to touch on points that may not be obvious to you and me reading this which puts a different speaking style on this compared to if we were talking one-on-one.


Thank you for the good questions. Enthusiasm like this, especially seeking information in another language shows a very high level of interest and that's what makes the knives we love so special.

Much appreciated.
 
I never asked for details , I never asked for propriety knowledge, I don’t want to make knives myself….! Why do you pin such things on me that I never mentioned or asked for?


I just want to know if the ratings between “pre Spyderco BB 15V heat treat” as used by Dr. Larrin in his publications and “after BBB Spyderco heat treat “ as used in 99.9% of the knives made in this steel makes would make a difference in the valuation of the toughness, edge retention and corrosion resistance of a blade. That is all I ever asked ? With this single simple question I have you try to set me up with :

Doubting the importance of dr. larrins work
Asking for details about production
Asking for propriety knowledge
I should make knives myself
Trying to solve mysteries about how things work

Why do you do that? Again my single question is as simple as I re wrote at top of this post. Nothing less , nothing more….
 
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DeadboxHero said:
You asked for leniency for not being a native English speaker, I ask you for the same in return. It was not my intention for a negative context on that.

I was assuming we are like-minded. I want to know how things work also which is what leads me to make things.






Yes, well we are not having a private conversation. We are having a public discussion, so the audience is everybody that reads even people that read this 10 years from now. So I have to touch on points that may not be obvious to you and me reading this which puts a different speaking style on this compared to if we were talking one-on-one.


Thank you for the good questions. Enthusiasm like this, especially seeking information in another language shows a very high level of interest and that's what makes the knives we love so special.

Much appreciated.
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Thanks Shawn for some understanding and empathy but still that does not answer my question . And that answer does not aks for any revealing of secrets nor do I have any hidden intentions that could harm any ones capabilities. Again the quesion is simple but no reply despite long extensive postings meanwhile 😅
 
Shawn wrote: “ If you have any thoughts about trying some BBB 15V time is running out. Crucible Industries LLC is gone and it will not make the transition to Erasteel.”

I have bought 2 of them and like the steel better then any other steel I ever used . 👏🙏
 
Larrin said:
Recently I was able to acquire a used CATRA machine, so I heat treated just about every knife steel I had, made 57 knives with the help of knifemaker Shawn Houston, and tested them all to see which cut the longest. For a few of the steels I did multiple heat treatments to look at a couple variables and to see the effect of hardness. I also compared edge retention and toughness to see which steels have the best balance of properties. https://knifesteelnerds.com/2020/05/01/testing-the-edge-retention-of-48-knife-steels/
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I like the toughness rating of NioMax. Do you have any data on the edge holding? Has it hit the market yet?
 
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