Fine Edge Retention

[catamount]

There's a lot of talk here about how long various steels will hold a working edge. However, there doesn't seem to be any direct correlation between working edge retention, and fine edge retention. You can have a steel that holds a working edge for a long time, but loses a fine edge fairly quickly (S30V being one example).

In your experience, which steel(s) hold a razor sharp, hair popping, edge the longest? For the sake of this discussion, let's make working edge retention irrelevant. It doesn't matter if it goes dull as a butter knife as soon as it loses its fine edge

[chuck_roxas45]

CPM-M4, XHP, and ZDP among the steels I have.

[Zenith]

My experience is limited, but CPM-M4 and RWL-34. RWL is an underrated steel IMO same as CPM-154

[dalefuller]

I haven't tried any XHP steels, but I have to agree with Chuck about ZDP189 and CPM-M4 being the longest lasting among the ones I've tried. I've had a couple of M390 knives but I didn't have them long enough to compare with M4 or ZDP189.

[catamount]

My experience is limited, but CPM-M4 and RWL-34. RWL is an underrated steel IMO same as CPM-154

Is RWL-34 the one that Des Horn has been working with, and likes so much?

[The Mastiff]

Is RWL-34 the one that Des Horn has been working with, and likes so much?

Essentially it's just CPM 154.

I'd like to add Super Blue to the list. It's sharp even when it's dull!

52100, O-1, 13C26, and a few more.

[unit]

No doubt in my mind CPM-M4 will put up with a huge amount of abuse and still shave arm hair, etc.

This is a video I did a while back of a practice session I did with a chopper made of CPM-M4. You will have to take my word on the matter that I did a LOT more than what is shown in the video prior to the edge demonstration...it would also shave leg hair cleanly in a single pass at this point.

Also worth noting, I reprofiled this edge. It is a bit thinner at 1mm behind the edge than many EDC blades you might carry.

<iframe width="420" height="315" src="http://www.youtube.com/embed/CR0jbSQghPk" frameborder="0" allowfullscreen></iframe>

It is worth noting that ZDP will also retain a keen edge VERY well, but it will not put up with this sort of percussive cutting. If you are using a folder sensibly, ZDP will amaze your friends

[Zenith]

Is RWL-34 the one that Des Horn has been working with, and likes so much?

The one I believe you are referring to is Nitrobe 77. I wish I could afford that! Very expensive steel. Rwl-34, Des was involved in that to as Mr. Loveless, and if you google it there should be a few discussions on the steel. It is a very fine structure and CPM-154 took a while to get to the same level I believe when Des visited Crucable.

It reaches 62HRC with normal HT and Tempering process but still has its corrosion resistance. I want to get it at a few different HRC. Apparently it can reach 65HRC, loses some corrosion resistance. I want to get a chopper made to really test its performance.

[Zenith]

I appologise for my poor sentences and spelling. Strugling on the phone.

[Ankerson]

That would be S110V at high hardness (63+ HRC) and tempered properly by far.

CPM M4, XHP, ZDP, M390, ELMAX, CPM 154.

Also A11 (10V and K294), better than any other steel above.

[JD Spydo]

ZDP-189 has been my best and longest lasting up till now.

I have another steel and an old one at that>> I find that 440V ( S60V) which is the predecessor to S30V to be able to hold a good edge even under some of the most horrible punishment. It may not be the "find edge retention" you are looking for but it is a special steel at any rate. There are properties I still like about it over S30V.

I'm really looking forward to getting that Caly with the Super Blue Steel >> I've heard nothing but good about it. JD

[gull wing]

Glad I read this Post.
It confirms the reason I like CPM154 so much. I have two blades in this fine steel (3/32" & 1/8") they both satify my need for a very sharp knife that holds for a decent amount of time. Wish Spyderco would make one in the stuff.

I am carrying a Chinese in ZDP189 right now. :)

[Cliff Stamp]

There's a lot of talk here about how long various steels will hold a working edge. However, there doesn't seem to be any direct correlation between working edge retention, and fine edge retention.

You are going to get a large variance in feedback here until you narrow down two things; what is the edge angle you are using and what polish do you use to finish the knives?

If your edge angle is high (15+ degrees) and/or your edge finish is coarse, then steels will stay sharp the higher the carbide volume and the harder the edge and the lower the amount of retained austensite.

If however your edge angles are low, your edge is highly polished then steels will stay sharp the lower the carbide volume, the harder the steel and the lower the amount of retained austensite.

Note the list Mastiff posted is of the second type (low carbide), the list Jankerson posted is of the first type (high carbide).

Note regardless of the type, all steels will blunt very quickly fast if they are not properly deburred. This is one of the reasons why some steels get a reputation for fine edge holding as they simply don't burr much in sharpening.

For example, ATS-34 at 58 HRC will burr much more readily than 8Cr13MoV at 61 HRC. Thus even if you use high edge angles where AST-34 should be able to hold a high sharpness, if you don't deburr it 8Cr13MoV will still be superior - this sharpening skill will make a large difference.

[PocketZen]

If your edge angle is high (15+ degrees) and/or your edge finish is coarse, then steels will stay sharp the higher the carbide volume and the harder the edge and the lower the amount of retained austensite.

If however your edge angles are low, your edge is highly polished then steels will stay sharp the lower the carbide volume, the harder the steel and the lower the amount of retained austensite.

Note the list Mastiff posted is of the second type (low carbide), the list Jankerson posted is of the first type (high carbide).

Very helpful thanks! :)

[Fifteen54]

you are going to get a large variance in feedback here until you narrow down two things; what is the edge angle you are using and what polish do you use to finish the knives?

If your edge angle is high (15+ degrees) and/or your edge finish is coarse, then steels will stay sharp the higher the carbide volume and the harder the edge and the lower the amount of retained austensite.

If however your edge angles are low, your edge is highly polished then steels will stay sharp the lower the carbide volume, the harder the steel and the lower the amount of retained austensite.

Note the list mastiff posted is of the second type (low carbide), the list jankerson posted is of the first type (high carbide).

Note regardless of the type, all steels will blunt very quickly fast if they are not properly deburred. This is one of the reasons why some steels get a reputation for fine edge holding as they simply don't burr much in sharpening.

For example, ats-34 at 58 hrc will burr much more readily than 8cr13mov at 61 hrc. Thus even if you use high edge angles where ast-34 should be able to hold a high sharpness, if you don't deburr it 8cr13mov will still be superior - this sharpening skill will make a large difference.

+1

[chuck_roxas45]

Maybe for purposes of discussion, we should assume that sharpening skill is equal.

[DCDesigns]

I have found that my longest lasting razor edges are in CMP-M4, and M390. Super blue also holds that razor edge forever as mastiff mentioned, but its a little harder to tell when its lost it, since it does slice pretty much no matter what (also as mastiff mentioned)

I think its worth discussing what leads to this "razor edge" being easier to keep on one steel opposed to another. I assume particle size has a lot to do with it as well as carbide content. More educated steel nuts, please chime in!

[Ankerson]

Maybe for purposes of discussion, we should assume that sharpening skill is equal.

There really are a lot of variables to take into count.

The media being cut.

Edge finish.

Edge geometry.

The steels themselves as all companies have different methods.

The basics hold up though, the higher the alloy content (Carbide Content) the better the edge retention will be assuming a good HT and tempering process.

High Carbon steels with high alloy content that can be taken to a high HRC hardness will give the maximum performance as in edge retention.

There really aren't any free lunches here and the only way to really get the max out of the steels is to go with Custom knives with Custom heat treating.

That said 10V will make CPM M4 look like 440C in comparison......

That said this stuff about fine edge retention......

I am guess those who are worried about it really aren't cutting much with their knives or using them that much because if they cut anything that is abrasive that fine edge will be gone very fast. Just keeping it real here.

[chuck_roxas45]

...if they cut anything that is abrasive that fine edge will be gone very fast. Just keeping it real here.

Indeed...

[Ankerson]

Indeed...

I think they are looking for something that just doesn't exist currently and definitely not in production knives.

The steels just ain't there nor is the hardness and the tempering process.

That is if they are cutting more than a bag of chips or opening mail.

That is unless they are farming out to someone with a 10 Bar + Furnace and getting MAX hardness, that's getting into Aerospace quenching speeds...

That really wouldn't be in a production companies best interest any way though because they just won't know how all the knives would be used.