Ranking of Steels in Categories based on Edge Retention cutting 5/8" rope

LX_Emergency said:
I'll have to get you some to play with then.

I'll get in touch as soon as I'm ready to send you some to play with. It's not in the league of m390 and such I suspect. But I like the stuff anyway.
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Looking forward to it. :) :thumbup:
 
I have a knife that I've been using for am edc for around a year now in that steel. It's got some cosmetic flaws (which is why I picked it for myself instead of selling it) but the grind and heat treatment are good. As soon as I figure out what I'll cary as a replacement I'll get your details and send that over to you. It'll probably be sometime next week.
 
LX_Emergency said:
I have a knife that I've been using for am edc for around a year now in that steel. It's got some cosmetic flaws (which is why I picked it for myself instead of selling it) but the grind and heat treatment are good. As soon as I figure out what I'll cary as a replacement I'll get your details and send that over to you. It'll probably be sometime next week.
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Sounds good, let me know. :)
 
Added Phil Wilson Custom in CPM M4 at 65 RC and .015" behind the edge.

Harder use type knife.
 
Jim, or if Phil is looking on, what kind of toughness remains in M4 at that high hardness of 65?
 
Thanks for the testing Jim. I test every knife I make but sometimes it is very helpful to have someone else to compare results with. I use a little different test method than Jim but the overall results have tracked very close. We have done experiments with different geometries (thickness behind the edge) heat treats and sharpening and many of the results show up here in Jim's ranking. The amount of data Jim has generated here is extensive and the results of a huge amount of time work and expense. Jim has laid it out for every one to see and for each to interept as they wish.

The knife tested here was made for SurfingGringo who does a lot of salt water fishing. I anticipated some heavy cutting through fish bones and heavy scales and skin so the geometry behind the edge was left a little heavier to compensate. CPM M4 overall is not the best grade for the fishing/saltwater/high/high humidity application but it does serve to put another point on the curve and some real life use in the field.

Black Mamba, To answer the toughness question: Before sending this knife to SG I did some aggressive cutting on seasoned fir and got no visible edge damage. I then whittled Bocote which is very hard like desert ironwood and i did get some visible deformation but no chipping. Pretty much exceeded the stress limit on the edge. In addition SG may come on and relate what he did with the knife, cutting through some heavy fish bones. This was a test knife and I am still working on CPM M4 heat treating. On subsequent knives I have dropped the hardness to 63/64 for a little more ductility on recent blades that were ground to a thinner profile behind the edge (.006 or so). I am referring here to bending toughness, but impact toughness on all of these high alloy grades at this hardness is pretty low. Not intended for chopping and batoning and like use.

Phil
 
Thanks Phil. It's been a good ride that's for sure and I have learned a lot over the years with our coordination back and forth. :)
 
black mamba said:
Jim, or if Phil is looking on, what kind of toughness remains in M4 at that high hardness of 65?
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High mamba, I have been using that knife for the last 6 months or so. As Phil said that one has seen some fairly heavy real world use. I intentionally did a lot of pushcuts through large rib bones on large fish. Many of these cuts involved me putting my hand on the spine and using a lot of body weight. I wouldn't say that I was trying to damage it but I wasn't far from it. I definitely haven't cut the knife any slack. Through 6-8 months of that use on an almost daily basis I haven't been able to hurt it. No chips, no rolls...nothing. That has been my experience.

Fwiw, I used it alongside some production knives in s30v with thicker edge geometry and I did see some noticeable (though minor) chipping in the s30v in the same work. I have also experienced some of the same damage using s90v. Those are real observations, but I'm not the most scientific tester out there so don't take it as gospel or anything. :).
 
And thanks for doing the testing Jim! Given my use of the m4 and some of the other knives/steels in your ranking that's right about where I would have expected it to come in.
 
Added Darrin Sanders Custom in CPM S35VN @ 62 - 62.5 RC and .006" behind the edge.

Knife photo.

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Impressive! That exceeds what I would have thought the alloy capable of, even considering the thinness and hardness. Darrin was having a very good day when he made that knife. :)
 
Fancier said:
Impressive! That exceeds what I would have thought the alloy capable of, even considering the thinness and hardness. Darrin was having a very good day when he made that knife. :)
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I will let Darrin ring in on that. :)
 
Thanks Fancier. It exceeded my expectations as well. I was expecting it to fall into the 600 range. I have a few S35VN blades in the hands of some customers and I've been keeping tabs on them. They include kitchen knives, hunters, & EDC's. Everyone reports excellent performance in all areas with no complaints.
The only thing I changed about the H/T procedure on this knife is I used LN2 instead of dry ice/alcohol. In my opinion, this level of performance coupled with a straightforward H/T & ease of grinding/finishing makes this one of the best all around steels available today.
 
Darrin,

Well it's my new kitchen knife so you will be getting some feedback from me also. :thumbup:

Going to test it for ductility on hardwood next to see how it does, other than that it's looking good so far.

Jim
 
Good to know its gonna get used, especially by someone who knows a little bit about knives. ;)

Thanks for testing it Jim.
 
That really (pleasantly) surprises me. I wouldn't have guessed that level of performance, but it is thin and hard. Darren seems to be raising the bar on lots of steels, love reading about it!
 
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