Knife Steels
Which knife steel is the best?
That's not a simple question to answer. We all have our opinion based on our own experiences and experiences of others which are normally conveyed through personal contact (having a chat) or written (books, article, internet forums etc.). The internet is a great source of information, but unfortunately it is also awash with misinformation, part-information, information taken out of context, half truths and a load of b.s. A lot of what is out there is simply peoples opinion based on the aforesaid dubious information.
To answer the question, I'll use a car analogy. Which car is the best?
Not so simple to answer... there are a whole lot of factors to consider. Some of those factors may be important to you but not the the next person. Context is also important. Best for what? What kind of knife is it and what sort of work will it be doing (if any)? What is the process used to make the knife?
As a knifemaker, I will try and present my opinion on knife steels to give you an idea of what some of those decision factors may be and also to try and show why I use particular knife steels. I will cover mostly steels that I use or have direct experience with in the handmade knife world. The others are popular steels that I have included to provide some sort of context/comparison with.
Application
One of the first things to consider is application - what the knife is for. Is it made to work hard chopping down jungle? Preparing food in a kitchen? Breaking down an animal in the field? Peeling an orange while sitting in the sun? To be braggable to friends with some occasional use? Or to just look stunning and sit in a display cabinet? Does it need to be corrosion resistant because it's used around salt water?
In the world of knife steels, there are steels that are more suited to one application than the other. What are you going to do with your car? A Formula 1 race car would be without equal on the race track... but not so good to take down to the shops for some milk and bread... and probably wouldn't get more than a mile into an off-road rally like the Dakar.
Factors
There are potentially a ka-zillion different factors to consider. In the world of knife steel, the three main factors are Toughness, Edge Retention and Corrosion Resistance. Toughness would be the ability of a blade to take a beating and not break or chip. Edge Retention is the ability for a working blade to hold an edge - how much cutting will it do before it gets blunt. There is also relationships between these two factors. Example: a very high toughness will help prevent the edge from rolling or chipping during heavy use... so in some circumstances this will result in a seemingly better edge retention. This is known as 'edge stability'. Corrosion resistance is probably the most straight-forward of these with three main camps; 'Carbon Steel' which will rust if not taken care of, 'Stainless Steel' which is very corrosion resistant (but not completely) and 'High-alloy Steel' which is somewhere between the last two. Again, there are relationship between all these factors. Example: If a Carbon steel blade corrodes, at a micro level, this dulls the cutting edge. So poor corrosion resistance in some circumstances could lead to poor edge retention.
As a knifemaker, there are other factors to consider. Here are some:
- How hard a steel is to work - a steel that is difficult to work will take longer to make into a knife and thus impacts the end price, not to mention the potential frustration (never a good thing for a handmade product).
- The final finish of a steel - not all steels are equal when finishing and will provide a different 'look' and not all final finishes are possible with all steels.
- What steels are available at a given time - access to knife steels all over the world has never been better, but it is still a niche material with long lead times and complex production processes that can impact availability. Supply and demand - this also impacts price.
- The dimensions of steel available - if a producer only produces a certain steel in 3mm sheets, it can't realistically be used to make a big 8" Bowie.
- Price - modern 'super-steels' are fantastic, but they come with a price tag and not all customers are willing to or have budget to pay this extra cost. Shipping also impacts the price. Example: US manufactured steels are more expensive in Europe than the equivalent European manufactured steels.
- The state of the steel and finish when it is supplied - A lot of the time, I use the mill scale from the manufacturing process on the flats of my knives. I like this aesthetic and so I prefer steel that is supplied with mill scale.
- Manufacturer - A lot of generic steels (e.g. O1, the 10xx series of carbon steel) come from unknown manufacturers. The exact mix of elements in the steel, the purity and quality are unknown. Some of it is good, some is ok... and some is just crap.
Hardness and Heat Treat
Generally, the hardness of a steel in the knife world is measured in 'HRC'. This is roughly translated as Hardness on the Rockwell 'C' scale. There are other measuring systems (Vickers, Brinell etc.) but HRC has become the most common used for blades. Many beileve the steel hardness is the main factor in determining the performance of a blade - but this is just part of the story. As you increase hardness of any given steel, you increase edge retention, but you also reduce toughness. You generally want to get a specific steel as hard as you can without sacrificing too much toughness (also to an extent, corrosion resistance). Each steel is different in this regard and has a 'sweet spot' in hardness. But, this can also vary dependent on the application - do you need a tougher blade, or one that performs better?
The heat treat protocol and procedure is critical in determining the final hardness. It's a bit like baking a cake... if you follow the recipe to the 't', the procedure and other factors are the same, you should get the same result... every time. Unfortunately, most mass produced or even semi-production knife manufacturers cut corners in the heat treat process in order to make hardened blades quickly and cheaply. I have a semi-production folding knife that wasn't cheap. It is in S30V which is a very good knife steel. But, I have 10Euro cutlery in the kitchen drawer that hold an edge better than that folder. It is far better to have a blade in an inferior/cheaper steel that is correctly heat treated than a blade in a fancy/expensive steel that isn't properly heat treated. Most custom knifemakers will have a dialled-in process and attention to detail to ensure that you get the maximum you can regards toughness, edge retention and corrosion resistance for a given steel.
On the table below I have given the 'sweet spot' hardness (in HRC) that I harden the individual steels to.
Sharpening
A quick word on sharpening. If a steel is generally considered to be 'difficult' to sharpen - I find that to really mean that it takes me longer to bring up a burr when sharpening a blade or just honig an edge to touch it up. I wouldn't consider that more difficult... but just more time consuming. But, that's me sharpening on my equipment. It may be a different experience for others using different methods. As a general rule of thumb, the harder a steel (HRC) and the better the edge retention, the more 'difficult' or longer it will take to sharpen. If you want performance, you have to pay for it... in more ways than one!
Comparison
Here is a table of most of the knife steels I use with a few others for comparison as measured against the three main factors above. These measurements are (more or less) taken from data provided by Dr. Larrin Thomas.
Knife steels and the metallurgical science around them is a very deep and fascinating subject. Dr. Larrin Thomas' book 'Knife Engineering' does a superb job of explaining this science in lay-mans terms (442 pages of mostly understandable info). Dr. Thomas' website www.knifesteelnerds is also a fantastic resource for information and in-depth articles on knife steels. What I love about Dr. Thomas' work is that it is scientific and based on his own research and testing.
Carbon Steels
All carbon steels are not corrosion resistant (in their bare form) and will rust. A patina on the surface will help prevent corrosion as will a thin coat of oil or wax. Generally cheap, easy work and to easy to sharpen
O1
Often considered a 'beginner' steel for knifemaking. This is simply not true - I learned the hard way that O1 is quite sensitive to the temperature used for hardening it. Too hot and the steels' toughness drops off dramatically. If hardening out of a forge and not a temperature controlled kiln, there is a very good chance you'll have a hard but brittle knife. You'll only find out when your blade snaps!
O1 has been around since ?? and is still favored by many Bushcrafters because it is relatively easy to sharpen. O1 was the first Carbon steel I started using but now only use it on request - I think there are better Carbon steel alternatives like 26C3 or 52100.
Pro: Cheap
Easy to sharpen
Widely available in many sizes
Con: Temperature sensitive during hardening
Tougher and better Edge retention carbon steels available
Generic steel normally with an unknown manufacturer - varying quality.
1070
A good carbon steel in the 10xx series with a relatively low amount of carbon. The '70' denotes 0.7 % carbon in the steel. This low carbon makes it super tough and ideal for long blades like swords, spears and daggers.
Pro: Cheap
Tough!
Con: Not great edge retention.
Generic steel normally with an unknown manufacturer - varying quality.
1095
A decent carbon steel in the 10xx series with a relatively higher amount of carbon - 0.95 %. With the right heat treatment, you can get a great performing blade. With the right amount of Mag ?? in it , you can also get a decent Hamon from 1095.
Pro: Cheap
Easy to sharpen for the beginner
Widely available in many sizes
Hamon possibility
Con: Tougher and better Edge retention carbon steels available
Generic steel normally with an unknown manufacturer - varying quality.
80CrV2
Sometimes called 1080 'plus' or something like that. 0.8 % Carbon makes a great all-rounder. Used a lot for forging.
Pro: Cheap
Great for forging
Widely available in many sizes
Con: Generic steel normally with an unknown manufacturer - varying quality.
26C3
Manufactured by Uddeholm - excellent quality. Tougher than O1 with similar edge holding performance. You can get great Hamons with 26C3 - this is not only aesthetically pleasing (to me) but with most of the blade softer and the edge very hard (around 63 HRC) it combines the best of both worlds. You can get an extremely tough blade that is super-sharp and performs.
Pro: Cheap
Great Hamons / differential hardening
Quality steel made by Uddeholm
Con: Not widely available
52100
Commonly used for ball-bearings and often forged from them - ones the size of a tennis ball! Excellent toughness that makes it a great steel for the kitchen with thinner blades.
Pro: Cheap
Very tough - great for thin and/or flexible blades
Con: Not widely available in thicker stock
ApexUltra
The latest carbon steel - only launched in 2022. Brainchild of Tobias Hangler - designed for forgability and high performance. Great toughness from such a hard steel (66HRC) with excellent edge retention for a carbon steel. Probably the ultimate carbon steel.
Pro: Excellent performance/edge retention
Great to forge
Manufactured by reputable foundries in Europe - quality!
Con: Expensive
Not widely available - especially outside Europe
High-Alloy Steels
High-alloy steels are considered semi-stainless and generally give better edge retention than carbon steel. I like using them for those reasons and when you need a darker final finish like a stonewash. They have been known to be difficult to sharpen.
D2 / K110
A high-alloy steel developed in ?? by ?? for??. D2 is the generic steel whereas K110 is the same recipe manufactured by Bohler.
O1 has been around since ?? and is still favored by many Bushcrafters because it is relatively easy to sharpen.
O1 was the first Carbon steel I started using but only use it on request now because I think there are better Carbon steel alternatives like 26C3.
Pro: Great balance of toughness, edge retention and corrosion resistance
Nice mid-grey patina/stonewash finish
Con: Known to be difficult to sharpen
Cru-Wear / Z-Wear
Manufactured by CPM ?? - a quality steel. Excellent toughness combined with very good edge retention. A great steel but a bit of a dog to work with and difficult to find in different thicknesses in Europe.
Pro: Excellent toughness
Very good edge retention
Con: Known to be difficult to sharpen
Not readily available in Europe
K390
Manufactured by Bohler using powder metal technology - a high-alloy super-steel. One of the kings of edge retention but an absolute s.o.b. to work with!
Pro: Supreme edge retention
Reasonably tough
Con: Definitely difficult to sharpen
Very difficult to work
Stainless Steels
Stainless steels are corrosion resistant - but they are not rust proof. All steels will eventually corrode under the right circumstances. A very high amount of Chromium is normally the element that lends the corrosion resistance to steels... anywhere for around 12% up to over 20% for most stainless steels. But there are many other elements in the recipes for steels that give them thier unique properties... the manufacturing process also plays a role (e.g. powder metallurgy).
N690
Manufactured by Bohler since ??. N690 is a great all-round steel that is readily available in many dimensions. I would conisder it a step up from 440C which is very popular in the US and has become one of the standards for handmade knives in Europe and South Africa. It is very similar in composition and performance to VG10 form Japan.
N690 is the fist knife steel I used when I started my knifemaking journey as a teenager in South Africa. Although I consider it a starting point for stainless it will still outperform most stainless steels you'll get on a factory made knife... by far. It does the job!
Pro: Readily available (in Europe)
Reasonably inexpensive
Great all-rounder
Normally supplied with the mill scale :-)
Con: Fine grain-like structure can be seen when finished 800 grit or finer... but most folks don't notice this
VG10
Manufactured by ?? in Japan since ??. Originally marketed as this mysterious super-steel from a land afar. A good all-rounder and comparable to N690. I normally use it as the core layer in factory manufactured San-Mai / Damascus from Takefu.
Pro: Great all-rounder
Factory manufactured San-Mai / Damascus
Con: Can be expensive as a mono-steel
AEB-L
Manufactured by Uddeholm in Sweden since ??. Originally developed as a steel for razor blades... I believe most razors are still mde form AEB-L. A very tough stainless, ideal for thin blades or blades where you need flex. It's become very popular for handmade cullinary knives in the last few years.
Pro: Toughness!
Cheap for a stainless
Con: Poor edge retention for a stainless
Generally only available in thin stock
Elmax
Manufactured by Uddeholm in Sweden since ??. A powder metallurgy steel that's very well balanced. An all-rounder that is a step up from N690/VG10. Being a powder metallurgy steel, it finishes beautifully and is also relatively easy to work. I like using it.
Pro: Great all-rounder/well balanced
Beautiful finishing
Relatively easy to work.
Supplied with mill scale
Con: Expensive
RWL54 / CPM-154
CMP-154 is manufactured by CPM in the US since ??. RWL34 is the same steel manufactured by Damasteel in Sweden and is the basis of thier beautiful patterned/Damascus stainless steels. A modern, powder metallurgy steel that was poineered by the great Bob Loveless (hence the name: RWL). Another great all-rounder that is similar to Elmax... a bit tougher with a little less edge retention. But... with that additional toughness one could argue that it has better edge stability than Elmax. Perhaps... but it also finishes beautifully.
Pro: Great all-rounder/well balanced
Beautiful finishing
Damasteel!
Readily available in Europe
Con: Expensive
M390
Produced by Bohler since ??. A modern powder steel and considered one of the 'super-steels'. Excellent edge retention and corrosion resistance and finishes superbly. A high-end steel for high-end knives. I love this steel!
Pro: High performance - excellent edge retention
Beautiful finishing
Supplied with mill scale
Readily available in Europe
Con: Very expensive
One of the more difficult steels to work
M398
It's a bit like a newer version of M390 from Bohler. A 'super-steel' with fantastic edge retention and a higher 'sweet spot' HRC but at with a little less toughness than M390. Launched only a few years ago but it hasn't really taken off. As a result, very limited availability for this awesome steel.
Pro: Vey high performance - fantastic edge retention
Beautiful finishing
Supplied with mill scale
Con: Very expensive
Limited availability
A difficult steel to work
Magnacut
The new kid on the block from CPM in the US with rave reviews. Only released a few years ago, this new 'super-steel' is what folks are talking about and is in high demand. Is it as good as people are saying it is? Hmmmm. Maybe. Toughness is where this steel shines. Edge retention is more on the level of Elmax/RWL34. The added toughness will certainly help edge stability and lends itself well to applications where a tough steel is needed. In my mind, the biggest advantage of such a tough steel is that you can make a knife with a finer geometry - this makes it cut better and also allows a lighter blade (which is not always better).
Finishing this steel is a problem. Up to 180 grit it is fine... a bit like Elmax/RWL34/M390... but once you go into the finer grits it becomes an absolute pig. It is really difficult to get a great finish on it. The higher grits just tend to polish the steel rather than cut it... so you have to work real hard and go through a lot of abrasive to get an 'ok' finish. It doesnt come close to the lustrous satin finish you can get on Elmax/RWL34/M390/M398. But this is not really a problem on a working knife isn't it.
What I really like about Magnacut is that it goes somewhere most modern steels haven't gone - it fills a gap and offers a bad-ass stainless that will put up with abuse. But, I don't believe it's the best steel for all applications - I think most folks don't really understand this and just go along with the noise. A problem I have with the hype around Magnacut is that Dr. Larrin Thomas has become incredibly influential in the knife steel space (and rightly so...) but, he is also the creator of Magnacut and has a commercial interest in it being hyped up and thus driving demand for it.
Pro: Excellent toughness
Supplied with mill scale
Con: Very, very expensive (supply and demand baby!)
Sporadic availability until recently
A difficult steel to work
Very difficult to get a good finish on