Editor's Note: This Part II of Cedric and Ada's take on steels. For more see Part I here.
To paraphrase Sal Glesser - when it comes to steel you have edge retention, toughness and stainlessness. You can pick two, or all three if you spend a whole lot of money.
In assessing knife steel edge retention, there are two forms of data that will be available to you when you being looking for answers. The first and most plentiful is anecdotal. Untestable on its own, but able to form broad and often accurate data when widely collected from many, you will be able to find written accounts of how people feel steels have lasted on their particular, personal knives. widely
The second, rarer, form is empirical number ratings or lists - hard numbers that upon close inspection may end up being not so hard after all. Knife edges come in all shapes and sizes, and are very ‘list resistant’ despite most being made for the same purpose.
There isn’t one metric from best to worst that you can really hang your hat on, despite us all wanting one. Maybe me most of all. But I’ll go into what I have done:
In November 2016, shortly after the release of the Ontario Rat number 1 in D2 steel, I was in a rare position where I had two near identical knives, with the only meaningful point of differentiation being the blade steel. I thought it would be interesting to see how much longer D2 held and edge vs the AUS8 I was used to in my existing RAT 1, so I thought about a way to test the two of them as scientifically as possible, in a ‘playing at home’ sort of way.
I bought a hank of thick, fibrous manila style rope, and put the same edge on both knives with my Worksharp knife and tool sharpener using the 20 degree guide for each side of the edge. I cut rope using the frontal belly portion of the knife and when the knife would no longer do a papercut test (add a slight pinch to a sheet of printer paper to stiffen it and then slice), the number of rope cuts made would be its score.
The familiar AUS8 RAT 1 cut 58 passes, the new D2 model cut 120 times through the rope, indicating that between these two knives, and arguably between these two steels, the D2 would generally cut for about twice as long.
The knife community is hungry for stable and reliable data with regard to not only which steels are going to cut the longest, but which steels are ‘best’. I am hungry for that data myself. I grew up playing Role Playing Games (RPGS) like Final Fantasy, Baldur's Gate and their ilk, where your avatars success in various aspects of the game were presented clearly in numbers. It was a sure sign that, (unless the vague and ambiguous ‘Luck’ stat reared its head and caused a miss) that you know, in a rough realm, what your move is going to do. If you had lots of points in strength you would hit hard. If you had lots of points in dexterity, you would hit true.
Moving back to blade steel, there are various attempts to draw the same manner of system. A nice clean and easy graph listing best to worst. I wanted this too. I began to test every new knife steel I came across in the same way, hoping to form something resembling this for myself, and anyone else who was curious.
The two most prominent conclusions I have drawn over forty knives are:
1. There IS a general scale in which steels can be roughly ranked in terms of edge retention.
2. There are lots of things working against the player seeking statistical clarity, which I liken to the aforementioned ‘Luck’ stat, which will befuddle you if you try and look too close for absolute order.
Point One, General Trends
I am happy I have formed something of a general scale or list ranking the rough ordering of steels in terms of edge retention. There were few absolute shocks but some mild surprises.
1. Non-powder steels at the high end only begin to approach the lowest regarded powder steels and don't seem to meet them at any point by a fairly safe margin.
2. Things like nameless ‘stainless steel’ don’t hold an edge for any time at all.
3. Maxamet has amazing edge retention, as does ZDP189 and CPM10V.
These things were unsurprising to me and probably will be to anybody with an existing interest. As unsurprising as these statements are, it was heartening that my tests at a very basic level weren’t putting 420HC above S30V or anything particularly unexpected.
I am happy enough with the constants I can implement. I am satisfied that the absolute edge is about as identical as I can get with each knife. The worksharp edge adds a micro-convex micro-bevel that is visible to the eye. The belts show wear and degrade over use, and I have had to replace them numerous times. Turning the V ground factory edge on a mMaxamet Manix 2 to a convex Worksharp edge used an entire brown (mid grit) worksharp belt. CPM10V had a similar but less dramatic effect. The edges produced will shave, but not split, arm hair.
The rope is the same every time, and I cut this rope with the belly of the knife every time, a portion of about 1.5 inches of the total cutting edge. That these constants have resulted in a list that roughly, but not exactly, mirrors existing data from other sources, such as the CATRA card testing, or data from other youtubers and testers is heartening. All my tests can be watched in full on my channel, and I would absolutely always welcome someone buying the exact same rope and worksharp and replicating these tests.
In the end, I have basically formed a list of five components. Filling the bottom echelons are steels which are unsurprisingly easy to dull. Nameless steels, Gerber's mystery steel, Victorinox steel (which is not ‘bad’ by any sense - just brief at retaining a razors edge despite its other excellent attributes). Then we have the non- powdered steels. The classics from AUS8 through VG10 and D2 that we have been using for fifty years and have various levels of mastery from different producers and treaters. Then we have the standard powder steels, S30V through to CTS XHP. Steels that have great general attributes - their school report cards wouldn’t see anything lower than a C on any class.
Then we have the steels with exceptional edge retention, that begin to really put that crowd pleasing broadness of their more traditional PM cousins aside and push for absolute edge retention at the cost of all else. The fact that the Maxamet Manix 2 comes with a large packet of desiccant speaks volumes about what they have to ‘give up’ in exchange for the bonkers retention inside.
I am commonly confronted or challenged by people who thought one steel should be above or below another, in terms of a couple of places on the list. I generally tell them they may be right, as long as they aren’t intent on moving it down or up an entire class. The undetected bungles and micro-variables mean these numbers aren’t law, as I will now go into as part of point two.
Point Two, The Shakier Ground
I can’t test by Rockwell. There isn’t a central Rockwell number all steels can be brought to that I am aware of. MAYBE 59, but if you can convince Hitachi to give the guidance on how to get ZDP there, and then Spyderco to make a knife of it, then sure I’ll test it out. Let alone many companies don’t share (or know) exact numbers. How many times do you see 57-59 on a fixed blade or 60-62 on a folder? RPG Luck stat in effect right there, shoving around my data’s chance of a critical hit or miss.
There are a multitude of other butterfly effect stuff going on due to both micro- geometry, particle physics, chemistry and my own humanity that I will never attempt to hide. I will never tell somebody that my list is rock solid. I am always happy to retest steels I feel fell victim in a harsh way to the luck stat. Even now I look sideways at my HAP40 and M4 tests. They ‘feel’ a little low. Maybe they’re not and the hype is too high? I’ll be happier once I’ve tested each another two times at least.
One thing my testing can do is validate broader theories or beliefs, or take steps towards deflating them. Paul Bos truly can bring 420HC up to a level nearing or equaling some VG10. Zero Tolerance MAY adopt a lower level of edge retention, perhaps in the quest for robustness or toughness of their edges. Two ZT knives from authorized sellers performed at a lower level than S35VN from Reeve and Kizer, despite me doing multiple tests on each, thinning out the secondary bevels to put the idea of thickness hobbling the cutting performance to bed. This upset people a bit, but I’m not sure if they understood that: 1) I pull these knives from my own collection and most certainly want them to succeed. I have no horses in the race, I want every knife to cut its longest, as it is (generally) my knife; 2) I may have bought a soft pair of knives by sheer chance; or 3) They are softer for a reason, such as the aforementioned toughness in line with the ‘hard use’ marketing generally associated with the brand. I did have a mix of people in the comments of that video both confirming or vehemently denying the experience. The anecdotal evidence was split in that case. Further testing by me and others is certainly warranted before I would draw a conclusion on a whole companys' steel stock in the negative.
Conclusions and What To Do Now
A positive thing my testing has done for me is, when combined with data and knowledge of other attributes, pointed out some steels in which real magic seems to be happening when all factors are combined. I’ll go into some favourites now:
CTSXHP - What I know about this steel from my testing is that on a convex edge it cuts longer than S30V and S35VN by a decent margin. Decent enough to be fairly immune from any luck stat mischief. I also know it sells for a great price in the production world. That information is available and clear. What I also suspect strongly about XHP is that it has a good level of stain resistance and is not particularly hard to sharpen. It is a very complete steel for a folding knife.
ELMAX - What I know about Elmax is similar to what I know about XHP. It holds a great edge and is very stain resistant. What I also know is that it is becoming a mid-price powder steel, as Bohlers M390 sits on the darling throne. Paired with what I suspect about the steel - which is that is has great toughness and variety of uses (First Edge are making true beater fixed blades out of it and Bark River have used it as a staple stainless steel for years), and I am very happy recommending ELMAX to anyone. M390 has very similar properties - Survive! Knives will show you on their youtube channel some extreme testing. It’s just rather expensive still.
CPM3V and M4 - These guys surprised a few with their numbers being on the (objective) lower side. Both have a lot of positive press about them than seemed to have people (myself included) thinking that they would cut for days. The numbers are highly solid when you consider what I also know about the steels - they are incredibly tough. Bark River only have to use 3/16th stock of 3V when they make Bravo 1’s out of it. The normal steel is A2 at 1/4 inch. A2 is no pushover, toughness wise either. I have bent LT Wrights A2 Genesis in a log during testing and its came straight back to true once out. M4 is the bladesports steel of choice for choppers expected to cut 2x4s, rope, water bottles, and then standing toilet roll. These guys win big on toughness and edge retention in my opinion, which makes them very complete packages for impact or tasks where they might meet the odd twist.
CTS BD1 and 154CM - These two are high performing at a great price. They are non powder steels so will often be in the budget or basic price groups from folks like Spyderco or Benchmade. Their numbers are solid and especially with BD1 being sold almost price-matched with 8CR13MOV, its superiority is clear, and definitely worth spending what will probably only be an extra 5 dollars on.
Paul Bos 420HC - He gets a roughly 30% increase in edge retention with his treatment of this steel. I also suspect there are no issues with regard to drawbacks. If Bucks 420HC fixed blades were brittle we would have found out by now.
LC200N - This is my favorite steel for pocketknives. I know from my numbers it has mid to high range retention, and I also know from my corrosion testing that it resists corrosion at the same level as H1. Its unproven in fixed blades but for the Spydiechef or the Tusk, its a great attribute for those unusual patterns to have on board.
M390 - This, and probably its near identical twin brothers CTS204CP and CPM20CV, provides an excellent mix of known and suspected qualities, but you will pay more money for the privilege. In a world without money though, these would be the replacement for S30V in the standard ‘good pocket knife from a good company’.
The high achievers are great, but all of them bar M390 have drawbacks that might frustrate some. They will need a skilled sharpener or a sharpening system, and they will be prone to developing patinas or rusting. CTS40CP did wonderfully in edge retention but I didn’t have enough time with that knife to form opinion on much else. It may well earn a place in the above.
In terms of steels to avoid, well, I guess the numbers indicate, in a rough way where things sit. You make a choice about how often you are going to use the knife versus how good you are at sharpening. If you are getting a bit of pocket art/fidget fun first and cutting tool second, like the fabulous CRKT Swindle, then the 8cr is going to be fine. I would refrain from buying anything that isn’t labelled or just called ‘stainless’ or ‘rostfrei’, or just a couple of elements. I recently tested a knife from Aitor that had ‘cr mo va’ steel (those are the elements chromium, molybdenum and vanadium and are present in most blade steels) this name is like saying your car has a ‘turbo diesel’ engine and not saying any more about the cylinders, or the capacity. The knife was dull after 20 passes.
The final point I feel I need to cover is what level of edge retention we actually ‘need’ compared to what we want. I have never been a good freehand sharpener. I admire people who can mirror their bevels on waterstones to no end, but it never came ease for me and I’ve not had time to practice. I, like many, have a bought a system. Some folks choose edgepro, or Worksharp. For me, I like the Tormek watercooled whetstone guided sharpener. Whatever your method - skill or mechanical aid - I feel that it decreases the need for insane edge retention in the non-specialized (i.e. - not cutting high abrasives all day) user that has these means available.
People who perhaps use a professional sharpening service to keep their edges may find economy in the long term to buy their work knife in Maxamet so they only need to send it off a couple times a year. These folk may want the numbers as high as possible. For me though, with my ability to put a fuss free hair shaving edge on when needed thanks to the Tormek...well I would hesitate to say I ‘need’ anything more than VG10 on my daily carry blades. I don’t want to be at my sharpener every second day still, so I might not want to go much lower, but really, a month of carrying nothing but a Delica had me sharpen it twice, which wasn’t too painful at all. Despite it being rather low on the list, its still important to remember - the steel cut some pretty abrasive rope 75 times before it was dull. Thats a lot of fruit, paper, plastic tags and zip-ties.
And most importantly, low edge retention alone is no reason to close your mind to a certain steel. For the Swiss Army Knife, which is probably the most gifted knife in the world, there isn’t a better steel for the job, than the highly stainless formula they use. Victorinox know what their knives spend most of their time doing - sitting in utility drawers or car glove boxes of fathers and uncles who when they do reach for it, don’t want to see rust all over their blade. These users would hate that. It also balances magnificently with those who do use them often - the most common apple cutting knife in the world will not be effected by the acids in the fruit at all, and will sharpen up at camp on the side of your cooking pot or the lip of your enamel mug. Sure its low on my list, but as purpose-driven steels go its right up there.
So overall, all I can do is show you a set of numbers that I have put as much science into as a common man can, and encourage you to compare them with CATRA, with Michael Christy, with Cliff Stamp, with BLUNTTRUTH4U on youtube. If you want some great steel composition knowledge, check out Shaun at Big Brown Guy. Between many points usually lies the truth of something. I would love for another 5 guys to do similar kinds of test and make their own list and give the statisticians something to truly go to town on. But back to my own data, if the knife in your pocket is needing sharpening more than you want it, I would be pretty confident that looking upward on my list will probably find you something that will make you a little less busy on the stones. My tests will continue as my gotta catch em all mindset continues and I shop with ‘new steel’ as a priority.
Happy cutting, knife friends.
My testing playlist:https://www.youtube.com/playlist? list=PLl4xmeeE2PXwSdMyzoArEJhG_zPeiI6No
Cliff Stamps CATRA numbers: http://www.cliffstamp.com/knives/reviews/ CATRA.html
Michael Christy Youtube: https://www.youtube.com/channel/UCC-cvUqhuR-- z1uUAXqMzaw
Big Brown Guy Youtube: https://www.youtube.com/watch? v=05JDYWoqZoc&list=PLCqkKRvZd4uAtM2beXuPTxXPc1uQvBzPU
I think a lot of what Cedric and Ada wrote is correct.
PM steels are better than non-PM steels. There is simply no way to dispute that.
Second, get a sharpening system and practice a lot. Don't think that any system, no matter the cost, is going to work perfectly out of the box. Sharpening is a true skill and very, very few people can do it freehand with great proficiency. Even most knife makers need tools and guides. The 1 in a 1,000 or 1 in 10,000 that don't (and post videos of their skill at freehand sharpening on a show floor, for example) should not be used as the standard for the rest of us. Get a system and learn.
Third, think about what you are going to do with the knife. For me, I like simple, easy to sharpen steels for choppers (1095) and well-rounded steels for EDC (ZDP-189 and M390). I can see a case for 3V and A2 in choppers, but for me and my sharpening skills and use I get the most out of 1095.
Finally, here are my five favorite steels right now (July 2017):
1. 20CV: great all around performance and easier to sharpen than M390.
2. ZDP-189: very close behind 20CV but probably a bit more likely to tarnish.
3. CTS XHP: relatively cheap steel that is all-around great.
4. S35VN: similar to CTS XHP but usually a bit more money.
5. AEB-L: my only non-PM steel; hard and easy to sharpen. Michael Walker likes it and that is good enough for me.
1095: On a choppa, like a KaBar Becker, its great. Takes a beating and is easy to maintain (read: fix)
BD-1: This is a great steel, one of the best non-PM steels and it is cheap as dirt. And made in the USA.
Buck 420HC: the price of junk steel with performance of a midrange steel. Think of it as VG10 with no price premium.