Blade Steel Comparisons - Initial Report

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Vivi

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I recently got to work with a variety of folders in different blade steels to compare their abilities. Here are my initial impressions. I'm still sorting out some of the findings and re-testing others for the nth time, but all will eventually be posted. The knives were all reprofiled and then resharpened several times. Most had edges in the ballpark of 10 degrees per side. The angle measurements are estimates based on freehand sharpening angles (If you know of an easy way to measure them let me know). The sharpening process consisted of establishing a bevel with low grit sandpaper, then refining it with a fine DMT diamond stone, followed by a loaded leather strop. Microbevels and resharpenings were preformed using a fine ceramic rod followed by a strop.

If you know the RC levels for the steels listed could you let me know so I can edit the information into this post?

To view the composition of the steels please refer to the following pages:

http://spyderco.com/edge-u-cation/steelchart.html
http://www.crucibleservice.com/datasheets/index.cfm

CPMD2 - Spyderco Military - 20º inclusive with 30º microbevel
With this knife I was able to acheive the sharpest edge I've ever produced. CPMD2 showed an excellent capacity to keep extreme levels of sharpness. With other steels they would lose their hair popping edge rapidly then hold on to hair scraping sharpness for some time. Excellent edge holding ability in general. Showed a slightly increased tendancy to burr when sharpening compared to 440V and S30V. Much easier to sharpen than either of those two steels however. I'm curious as to whether the steel can be hardened to a higher RC level and if so how much it would increase edge holding and the ability to resist burring while sharpening.

D2 - Queen stockman - 14º inclusive no microbevel
Preformed similar to the CPMD2 knife except for a slightly increased tendancy to burr as well as losing its edge a bit quicker.

S30V - Spyderco UKPK, Manix, Native
The steel can be difficult to sharpen. It takes more strokes than the 440A or AUS8 knives to create a good edge. The resulting edge has a fine, consistent feel to it. Quick to lose the uppermost levels of sharpness but retains a working edge for considerable time. Very little burring when sharpening.

440V - Spyderco Military - 16º inclusive with 30º microbevel
The most difficult steel to sharpen out of the knives tested. Extremely little burring while sharpening and as expected excellent edge holding.

13C27 - Kershaw EnerG, JYD2, Storm and Speed Bump -
Sharpens very quickly. Shows a greater tendancy to burr than the other steels tested except for the 440A. Takes an extremely sharp edge but loses it much quicker than S30V or the D2 variants did. I think the steel would preform better at a slightly higher RC. I would love to get my hands on one of the 64RC knives in this steel.

440a - Kershaw Leek - 16º inclusive with 30º microbevel
Sharpens very quickly. Shows a greater tendancy to burr than the other steels tested. Takes a fine edge but dulls considerably faster than S30V, 440V and the two D2 steels. Edge holding was slightly lower than AUS8 and 13C27. In the future I'd like to compare this to a Buck knife in the same steel.

AUS8 - Spyderco Salsa, Boker Trance, Wharcom
This steel showed a high tendancy to burr on all three knives, somewhere in between 440A and 13C27 I'd say. Quick and easy to sharpen outside of the burr formation. Edge holding was good, but unremarkable compared to S30V etc.

8Cr13MoV - Byrd Cara Cara - 10º inclusive with 20º microbevel
The steel displayed minimal burring when sharpening, which can most likely be attributed to its high RC level (61rc I believe). The steel takes a very fine edge. Edge holding was closer to S30V and the D2 steels than 440A and AUS8.

----------------------------

Corrosion - The 8Cr13MoV developed some surface rust when exposed to sweat. The AUS8 Wharcom, 440A Leek and 13C27 Kershaws showed a much greater tendancy to rust than any of the other steels, though this is more due to the bead blast finish than steel composition. Once polished the steels showed no significant tendancy to corrode. No other corrosion was noted in the test knives.

The knives were EDC'd and used for general cutting tasks, going through several sharpenings, and used in a more controlled cardboard cutting comparison. The data from the work will be posted in the future.

If you have any specific questions about the steels or the knives tested fire away.
 
I don't know what the RC is, but will ad that I agree that Queen is doing a fantastic job with their D2. I've also reground my Queen edges to around 10-15 ish degrees per side and they perform great. They take and hold a great edge and I've had no issues of chipping or weakness or any of the theories that is commonly posted about problems with the larger carbide steels.
 
Body salts and perspiration can both cause corrosion, and different people with different body chemistries can have differing effects on steel. Polishing and teflon coating both retard corrosion; however, I met a guy a number of years ago who said he could rust any gun, even a stainless one, just by touching it. And I've seen numerous nickel-plated revolvers--beautiful jobs--with only a fingerprint or two marring the surface.

Your study is welcome. I do wonder about the Byrd Cara Cara having an RC of 61. Sounds a bit high, but I'd sure like to know the various Rockwells of your samples. How difficult is getting those numbers?
 
Unless Vivi got his info elsewhere, the original source of the 61 hardness was likely Cliff Stamp's web page. Cliff got the number from a post that Sal made on the Spyderco website forum. IIRC the post said that Spyderco had tested a pre-production sample. I say all this to say that it is unclear to me that 61 is the standard hardness for a Byrd. It could be the standard hardness, but I have not seen any actual hardness specification from Spyderco about the Byrd line. I don't own any Byrds, so I have not taken my own sample in to be measured in the test lab at work as I am wont to do with the few blades I buy each year.

I am quite willing to be contradicted by any fine upstanding Spyderco founder type gentleman and wish in no way to impugn either him or his company or the Byrd line in general as I admire them all greatly. I just looked up the source of Cliff's citation, which I have heard oft repeated as if it were a standard specification that all Byrd knives must meet.
 
No, it was not a pre-production sample and yes, that is the general hardness and yes, the source is Sal on the Spyderco forum.

Initially, the general production run of Spydercos were labled 440C due to a misunderstanding between Spyderco and the Chinese factory, because apparently the Chinese, familiar only with the European steel-naming scheme, thought that what they were using (the current Byrd steel) was called 440C in the States. The first production run (labled 440C) was Rced at Spyderco and Sal expressed a surprise that 440C could be hardened to 61 Rc while exhibiting the properties as the Byrd steel did (apparently 440C is really brittle at 61Rc). So an inquiry was started and misunderstanding was solved and the Byrds are now etched with 8Cr13MoV. To my understand, no further changes other than the etch on the blade was implemented. The new runs labled 8Cr13MoV should be identical to the older once labled 440C aside from the etch.
 
My Cara Cara was 58 RC and a Byrd Meadowlark was 60 RC when I had them tested. I would guess if you are seeing minimal burring they are near the top of the hardness range, though of 2 Kershaw Cyclones in 13C26 that I sharpened the softer one burred less, so go figure.

Good work, Vivi, that is a lot of cutting and sharpening. Good to hear you could get the CPM D2 nice and sharp. I found it similar to my Manix in limited sharpenings as far as burring and ease of sharpening, as both respond well to Shapton Glasstones and Spyderco ceramics with minimal burring. I plan on testing the Manix and CPM D2 Military head to head along with a highly beat on S30V Military that I was given that has tested better than any other S30V it was put up against in edge retention. The Manix is 58 RC, I will get the CPM D2 and S30V Military RC tested after my cutting comparisons.

Mike
 
gunmike1,
58-61 seems like a reasonable hardness range (and a pretty darn good one at that). Saying all Byrd knives reach a hardness of 61 does not seem reasonable, yet I have repeatedly seen that single number provided as the absolute hardness of all Byrd knives in threads posted here on the Forums. Nobody holds that tight a tolerance (i.e. ±0). (BTW Those threads that I remember reading were not posted by Sal nor by Spyderco.)

Thanks for sharing your data.

HoB, thanks for a fuller explanation of the background for that single number.

Vivi, thanks for compiling your results and presenting them. You have good information there.
 
440V - Spyderco Military - 16º inclusive with 30º microbevel
The most difficult steel to sharpen out of the knives tested. Extremely little burring while sharpening and as expected excellent edge holding
Click to expand...
.

This is one I'm having a difficult time with. This steel was run soft ( IIRC 55 to 56) due to chipping at higher hardnesses. I would have expected problems with 8 degree angles ( 16 degree inclusive) even with the 30 degree microbevels due to the composition and softness of the steels. This steel is all about wear resistance and not 16 degree inclusive angles. No bending or chipping out? Joe
 
Joe, the edge I described is what I've had on that Military for a few months now. It's mainly been used at jobs to cut plastic wrap and cardboard, cut and split wood outside and handle food chores. Haven't had any problems except for when I tried cutting a paper clip just to see what happens. The edge got a small dent in it where it sort of rolled / compressed. If 440V was only hardened to the mid 50's that's surprising considering how difficult it is to get a burr while sharpening it.
 
Yes, knarfeng, I agree, the single Rc number for the Byrds is certainly questionable. But in the same post, Sal stated that the Byrds were run slightly harder than was common on the Spyderco knives. Considering that the VG-10 is run, I believe, around 59-60 Rc and S30V either the same or a tad softer. I would imagine that the Byrds should come in around 60-61 Rc. I am not surprised though, that gunmike had one at 58 Rc. Considering that these are made in China and sold for a lot less than the Spyderco knives, I'd imagine that the tolerances are a bit softer than on their Spyderco counterparts.
 
Is it just me? A 58 to 61 RC point difference/range seems like alot even on knives with the Byrds price point.
 
Vivi, if you're not having trouble than I'm pleased. I wouldn't have the desire to thin it down that much unless I was testing. As far as burring I always had trouble feeling the bur with this one. I think even with DMT's I was probably pressing too hard. I do still have a unsharpened 440V/S60V millie laying around that is still pretty sharp. It doesn't get as much use as the BG42 model(s) I have as I like that steel much better. It is SE though.

Now S90V is brilliant. I fell in love with it instantly just like I did with ZDP( A MT sprint run Socom elite). A S90V millie will be coming out at some point in the future. S90V is traditionally run a bit harder than S60V and when it is you can really feel a difference. It's what cruicible's process is all about. To me the others (cpm154cm, s60V, cpmD2, etc. don't really show what the process is capable of. S60 came close but for whatever reason I never saw it past (guessing RC57). CPM D2 is IIRC RC 62 according to Spyderco and does pretty well, better than soft D2 , that's for sure.

I'm just rambling now. Please keep doing these type comparisons. We like them even when we are arguing and bitching. You write well and seem to keep things objective. A good thing! Joe
 
This is all from what I've read and learned and if there is a mistake feel free to correct me:

Blade steel/RC hardness:

420/55
420HC/56-57
440A/56-57
440B/57
13C27/59
440C/58-60
154CM/58-60
ATS-34/58-60
S30V/58-61
VG-10/58-61
D2/59-62

If anything is wrong just let me know, J.
 
batosai117 said:
This is all from what I've read and learned and if there is a mistake feel free to correct me:

Blade steel/RC hardness:

420/55
420HC/56-57
440A/56-57
440B/57
13C27/59
440C/58-60
154CM/58-60
ATS-34/58-60
S30V/58-61
VG-10/58-61
D2/59-62

If anything is wrong just let me know, J.
Click to expand...
Hardness of a bladesteel doesn't depend solely on the steel but mostly on the heattreat. So to list hardness values for steels like this is really meaningless. You have to add who heattreated the steels.
 
HoB said:
Hardness of a bladesteel doesn't depend solely on the steel but mostly on the heattreat. So to list hardness values for steels like this is really meaningless. You have to add who heattreated the steels.
Click to expand...

picky picky picky, *sigh* Okay, we'll have it your way, I'll site my sources.

Blade steel/RC hardness/Maker:

420/55/kershaw
420HC/56-58/buck knives
440A/56-57/kershaw
440B/57/internet source(kind of a given)
13C27/59/kershaw
440C/58-60/benchmade
154CM/58-60/benchmade
ATS-34/58-60/benchmade
S30V/58-61/benchmade or internet sources
VG-10/58-61/SOG or internet sources
D2/59-62/benchmade

If these are incorrect, feel free to add your .02, J.
 
batosai117 said:
picky picky picky, *sigh* Okay, we'll have it your way, I'll site my sources.

Blade steel/RC hardness/Maker:

420/55/kershaw
420HC/56-58/buck knives
440A/56-57/kershaw
440B/57/internet source(kind of a given)
13C27/59/kershaw
440C/58-60/benchmade
154CM/58-60/benchmade
ATS-34/58-60/benchmade
S30V/58-61/benchmade or internet sources
VG-10/58-61/SOG or internet sources
D2/59-62/benchmade

If these are incorrect, feel free to add your .02, J.
Click to expand...

Hob is correct. The Rc numbers are for the specific company using it, not in general the steel itself. There is a large range of Rc for steels depending on the HT. In general those numbers would be a good guideline and you might possibly go higher on a properly heat treated light use knife and you would go lower on a heavy duty hard use knife. For example, I have seen ATS34 at an Rc of 61 in a hard use knife. I have seen D2 at 63 in a light use knife.
 
Cobalt said:
Hob is correct. The Rc numbers are for the specific company using it, not in general the steel itself. There is a large range of Rc for steels depending on the HT. In general those numbers would be a good guideline and you might possibly go higher on a properly heat treated light use knife and you would go lower on a heavy duty hard use knife. For example, I have seen ATS34 at an Rc of 61 in a hard use knife. I have seen D2 at 63 in a light use knife.
Click to expand...

Well $hit on me! I only added the RC because the OP mentioned that if anyone happened to know the RC's to just add them.

Quote from OP from Vivi:"If you know the RC levels for the steels listed could you let me know so I can edit the information into this post?"

I stepped forward and put in my two cents on what I have seen in popular knife brands, kershaw, benchmade, sog, etc. The RC's that I mentioned I added to the end of them where I saw them from.

It is a general scale that I mentioned, 420 being the lowest, and the tool steels being the highest (stainless steel wise). The RCs that I brought up are generally the ideal RCs for the blade material, other wise it will be worthless as being too soft or too brittle.

Heat treat is everything in a knife, Buck uses 420HC, but with their great heat treat they can get their RC up to 58, and then with their blade geometry they have been proved to outcut several higher end blades.
 
batosai117 said:
Well $hit on me! I only added the RC because the OP mentioned that if anyone happened to know the RC's to just add them..
Click to expand...

Relax, it is just a discussion, no one is poopin on you, the info is appreciated I am sure. :thumbup:


Heat treat is everything in a knife, Buck uses 420HC, but with their great heat treat they can get their RC up to 58, and then with their blade geometry they have been proved to outcut several higher end blades.
Click to expand...

420HC is a good example of good heat treat on average quality steel. This steel is even lower in Carbon than 440A and yet it performs better than 440A. I have owned many buck knives(nighthawks and Intrepids) out of it and they all performed well. However, none of them shined in the edge holding department, they were good, but nothing compared to the higher carbon steel blades like S30V, VG10, ATS34, D2 and BG42, all of which had much longer lasting edges in my experience.
 
Cobalt said:
Relax, it is just a discussion, no one is poopin on you, the info is appreciated I am sure. :thumbup:
Click to expand...

Didn't mean to sound, well, mean. Sorry, just felt attacked when HoB called my info meaningless and then you kind of agreed. So I found my sources on where I got my info from.
 
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