CRKT AUS6M vs Other AUS6

S Dunbar · Apr 13, 2001

Following the subject in the thread below on M16's, I've been netting and searching.

It appears there a more than a few people disappointed with AUS6, but it seems that its primarily on CRKT knives. According to CRKT's steel specs, AUS6M has a hardness of 55-57RC, whereas according to Spyderco's info it is 58-60. Does this explain the different degrees of satisfaction.

I'm still waiting for my Spydercards (Damn Easter, they should have been here on Wed or Th, NOW I have to wait till next Tuesday

), and now I'm worrying about the AUS6 blades in them. Admittedly, they are more of a novelty item, but I hope they perform better than the AUS6M CRKT's appear to.
I'm also waiting even more impatiently for my Spydie Wegner in the same parcel, and I haven't even been able to find one to play with locally, I just decided it was the best choice based on info in these great forums. Anyone know of some great land in Florida for sale??

Frustrated, Stuart Dunbar

Bugs3x · Apr 12, 2001

From what I've read of complaints about CRKTs AUS6, it is more "steel snobbery" than any specific complaints.

But, to back up, the hardness scale is a function of heat treat and tempering. The higher the number, the harder the steel. By the same token, the higher the number, the more brittle the steel is. Makers attempt to hit a happy medium, with the general use/purpose in mind, and use a hardness level that has maximum edge holding (hardness) without brittleness -- loss of ductility. Spyderco is willing to make it's AUS6 blades a bit harder than CRKT.

Hardenability is based upon the ingredients added to iron. Carbon is the oldest ingredient so to speak. "High" carbon theoretically makes a steel hardenable to around 60C. Chromium makes steel harder in addition to making it stain less. One of the "oddities" in my mind, is CPM440V, now C60V or something of the sort. It has nearly 6% vanadium. This should allow this steel to be made extremely hard, yet it is usually used down in the CRKT range for AUS6. It still holds a terrific edge, but either ductility/shock absorption/or brittleness prevents using it as hard as one would think possible. (Tho, once again, I believe Spyderco uses it harder than other manufacturers.)

AUS6 doesn't hold an edge as well as AUS8 or ATS 34, or other stainless steels. But, it is more stain resistant than both those steels, and easier to sharpen. The easier sharpening follows the lower hardness, not stainless qualities.

If one is a hard user of knives, and doesn't like to sharpen them, then AUS6 isn't the best choice of steels. But, if one is like me, who always carries a knife, and am not fond of sharpening, and a bit slothful about cleaning/maintenance, then AUS6 is ideal, because of it's stainless qualities, and it' relatively low cost doesn't make me lose value in an expensive knife as my slothfullness might otherwise cause.

I believe that CRKT is concerned about the criticisms of AUS6. They've brought in "new", relatively unknown steels for a couple of their new models. And, they've used ATS34 right along for the Apaches -- now discontinued -- and their S-2s. So, it's not like they've only used AUS6 for steel. It could be that their heat treating isn't as good as that of some other manufacturers, but again, I've read few specific complaints about their AUS6, but a lot of, "that soft steel" and "that age-hardened cheese."

If you want bang for your buck -- or whatever they call a dollar there -- you can't do much better than CRKT. You might want to look at Outdoor Edge, their Magna uses AUS8. I believe the new Timberline Vallotten Discovery uses AUS8 also. I handled one of those last weekend and was very impressed with the fit and finish.

Sorry for rambling on so. Got interrupted halfway to make a chaueffer run for my daughter.

------------------
Asi es la vida

Bugs

S Dunbar · Apr 13, 2001

Thanks for the info.

I understand hardness and how its obtained, just not how it translates into real terms. How much different is 3 points RC in sharpening frequency (for eg. does it cut 50% more rope??)

Also I was wondering if Spyderco's AUS6 is really harder since there appears to be no Vanadium in their specs for AUS6 and who knows what "Sulpher" is.

With these typos, I was wondering if the Hardness was right, all the other data matched up with CRKT exactly.

Good that CRKT appears to be concerned, they should be

Still it appears that the happiest M16 owners are those with the AUS8 versions

Interesting you should mention Outdoor Edge, thats who I bought my knives off,(Australian Agent that is, www.outdooredge.com.au) now if only that damn parcel would arrive.

/Rant
Curse the postal system, "Queensland to Victoria??, only 2-3 days." Ha, 7 days later and I gotta wait for Easter now. Sniff.
/EndRant

S Dunbar

[This message has been edited by S Dunbar (edited 04-13-2001).]

James Y · Apr 14, 2001

IMO, AUS-6 is not a bad steel...there are certainly worse stainless steels out there. Spyderco's AUS-6 and CRKT's AUS-6M both have excellent corrosion resistance, and as mentioned above, the Spyderco version of it is a few points higher. I have heard that even a point or two higher or lower can make a big difference.
I do not think even at Spyderco's higher hardness that AUS-6 is brittle. IMO (depending on the steel, edge grind, blade shape, etc.), usually where just the hardness of the steel itself might create brittleness would be in the 59-62 range or above. Of course I'm not a metalurgist, but I find some knives at high hardness often just "feel" a bit more brittle; while the "softer" steels, though not holding an edge as long, can feel a bit "tougher."

BTW, I have and carry a Spydercard. I like this knife, AUS-6 or not. It takes a wicked edge and mine so far has held it quite well. The lock on mine positions perfectly, and no small moving parts to it.

Overall, I find AUS-6 to be a decent steel...several years ago it would have been a premium stainless. (Al Mar even used it in very good knives). One steel I would NOT want for a knife blade is 420-J2. It makes a decent liner material but not blades. You'll find that many very low-quality no-name knockoffs are made with 420-J2 blades. 420-HC however seems a pretty decent blade steel in my experience.
Jim

Sergiusz Mitin · Apr 13, 2001

Stuart,
Three points of difference in Rockwell scale are unnoticeable in knife practical use because this is within the range of natural measuring mistake. Please note that all manufacturers are specifying their blade hardness within approximately this range. It is impossible to obtain more accurate results when hardening and tempering blades.

In practice we can consider only that SPYDERCO try to harden their AUS-6 blades a bit harder than CRKT. Each knife maker or manufacturer has his own secrets about heat treating of particular steels and usually is not too willing to share them.

More, the hardness is not all for edge retention. Two blades made from the same steel and equally heat-treated can display pretty noticeable difference in edge retention regarding on blade geometry and even handle's shape.

As to steel, I think this is some kind of fault in SPYDERCO steel specification. Neither SPYDERCO nor CRKT makes this steel, basically the steel is the same.

THEAVENGER · Apr 13, 2001

Sergiusz Mitin is correct. AUS 6 is made by Hitachi. It is exactly the same no matter who uses it. The only difference is the heat treat.

Burke · Apr 13, 2001

I notice at the top that Mr. Dunbar mentions that CRKT uses AUS6M, and that Spyderco uses AUS6; is that a typo, or does the M perhaps stand for modified? I would also argue that a 3-pt difference can be substantial; see Wayne Goddard's edge-holding tests at http://www.ameritech.net/users/knives/edge.htm for some implied data in this area. Finally, I would note as an addendum to Sergiusz's comments that a three point range is not within a measuring error range, and that it is more within the margin of error of large-batch tempering. What does this mean? Most Spydercos will RC out to about 59, while most CRKTs will end up as close to 56 as they can get them. I think there is definitely a measurable (even if not tremendous) difference in edge-holding with a range like this. Just my .02, which is about a buck Canadian.

Cliff Stamp · Apr 14, 2001

The RC of a steel can be determined to far more precision that +/- 3 depending of course on who is taking the measurement and what equipment they are using. It can be done to an uncertainty of less than +/- 1 RC. As for the difference, a change in 3 RC can alter material properties by more than 100% so yes it can significantly effect performance. As for heat treat, this again can be done to a precision greater than +/- 1 RC.

-Cliff

Cosmic Superchunk · Apr 16, 2001

Personally I find nothing wrong with CRKT's AUS6 blades. I also have 2 Spyderco's with the same steel and like them as well. It all comes down to the user's choice. I can sharpen my blades when I need to and I think it's rather elitist to bad mouth it as an inferior steel just because CRKT's knives are not expensive. Yes edge holding is important, but price is also a factor. For instance, CRKT is about producing quality knives at a price the average Joe can afford. Now if they decided to make all their knives in 154CM or BG-42, the prices would naturally have to go up. You could easily buy 3 CRKT knives in AUS6 steel for the price of an Emerson production folder. Which will outperform the other? It depends on what you use the knife for and how often you use it.

S Dunbar · Apr 17, 2001

Many thanks for the response, and excuse the delay in acknowledgement.

James, Thankyou for the confirmation about Spydycards, I've just handled one once, and its nice to see that my impression of quality translates to the blade.

Serg, (djenkoe) I thought the same about the typos in specs, I was wondering who was wrong. I would have thought that the heat treating would be done by third parties, thereby confirming my opinion of Taiwan's production abilities. [Although to be fair, according to one business contact, they can make what you want for any price, the cheaper you want, the cheaper they provide!, so its more an issue of quality control]

TheAvenger, I thought there must be a common Mfr of the steel, nice to know who it is.

Burke & Cliff, I also looked at the tests, this was another reason for asking Re: edge holding vs. hardness. [I tend to regard any fact as requiring triple confirmation before I'll believe it, must be my scientific background

]
It would appear that it comes down to Quality control, thus Spydies come out on spec [whatever that maybe after typos

] whereas CRKT pay the price of Taiwanese manufacture. Cliff, is that a typical degree of accuracy for heat treating?, it would explain difference between Spyders and Crickets (it appears that all Spyders are produced in USA or Japan, probably the Number 1 & 2 in metallurgy)

El Cid, I understand your point about value for money, but what I am on about is that it appears that CRKT's AUS6M is inferior in hardening to other manufacturer's. I personally found this as a shock after the quality of design and assembly. I regard that price is a secondary consideration to perception of quality transmitted by the final product (I felt I was being lied to). In my currently devalued currency (Aussie dollars,{rubles,pesos,lira}) the price of an AUS6M Zytel model CRKT (m16-03z) is $80 and an AUS8 (m16-04) is $115. My opinion is that they shouldn't have produced the cheaper version, if I hadn't come to this forum and learnt the difference, I would never look at another CRKT again.

Thanks to all, Stuart Dunbar

[This message has been edited by S Dunbar (edited 04-17-2001).]

Sergiusz Mitin · Apr 17, 2001

Cliff,
Just would like to clear from engineering standpoint: measuring within 3 HRC and tolerance +/- 3 HRC is not the same, right?
In my humble opinion +/-3 HRC would be equivalent of saying "within 7 HRC range" (-3-2-1-0+1+2+3), isn't it?
Maybe it is possible to get heat treating accuracy certainly 57 (for ex.) HRC, no more and no less - but for what cost? And on how much pieces? And how certainly form one bunch to another? And, finally, why each solid manufacturer specifies blade hardness within 2-3 HRC, in another words +/-1 HRC?
Ooopss, one question more. How accurate can you measure edge hold if it is quite hard to consider the border between blade "shaves" and "not shaves", especially speaking about 2-3 next slices through hemp rope?

[This message has been edited by Sergiusz Mitin (edited 04-17-2001).]

Cliff Stamp · Apr 17, 2001

Sergiusz Mitin:

measuring within 3 HRC and tolerance +/- 3 HRC is not the same, right?

Unfortunately they can be the same or different. There is no universal standard for what such ranges actually mean. They are either the standard deviation or some confidence interval, the latter being some function of the standard deviation as well as a few other properties of the same (number of elements, degress of freedom, degree of confidence, etc. ).

There was actually a discussion about this either here or on rec.knives quite some time ago where someone asked what does 59-61 RC actually mean. Or in other words, if you were to pick a knife at random what is the probability that it will fall within the range of 59-61 RC. If I had to guess I would say that range is probably a 95% Confidence Interval, odds are if it is not that it is a standard deviation.

Maybe it is possible to get heat treating accuracy certainly 57 (for ex.) HRC, no more and no less - but for what cost? And on how much pieces? And how certainly form one bunch to another?

It is possible to get the heat treatment variance down to such an extent that if you round off the RC to no decimal places they should all be the same. Custom work of high quality should do this, if they have tight control on their heat treat.

Now you are correct of course that the cost is probably much more. Production companies are forced to work in much larger batches and in much shorter time scales so it is not surprising that they will have a large variance in the RC produced. It would obviously cost more as the precision of the heat treating process is increased, how much and to what extent I have no idea.

why each solid manufacturer specifies blade hardness within 2-3 HRC

They don't. Cold Steel actually has a bit about this on one of their webpages saying basically that a difference of a few RC can make a significant impact on the performance of the steel and that there steel is specified at a RC, not a range of hardness.

Note as well comments like the following :

I've been told that the "comfort range" for BG-42 is 62-64. I think we are shooting for the lower end of that range.

from :

http://www.bladeforums.com/ubb/Forum3/HTML/002249.html

This implies that the level of control is much better than a random scatter between 62 - 64 RC, it in fact a controlled effect to concentrate the hardness around 62 RC.

How accurate can you measure edge hold if it is quite hard to consider the border between blade "shaves" and "not shaves", especially speaking about 2-3 next slices through hemp rope?

Not very well mainly because it is a judgement, but also because the changes can be small and thus you tend not to see them, reason why you don't notice yourself growing taller for example. If you want a higher accuracy and/or precision then don't use shaving as a means of determing sharpness. For a total picture you want to look at both push cutting and slicing ability.

-Cliff

Sergiusz Mitin · Apr 17, 2001

Cliff Stamp:

Unfortunately they can be the same or different.

Fortunately - no!
The hardness 57 +/-3 HRC in fact means range between 54 and 60 HRC. Hardness variations within 3 HRC range mean variations from (for ex.) 55 to 58 HRC. Somewhat differs, doesn't it?
English in not my native language but small bit of common sense is quite welcome to help people to understand each other, of course if they want to understand.

It is possible to get the heat treatment variance down to such an extent that if you round off the RC to no decimal places they should all be the same. Custom work of high quality should do this, if they have tight control on their heat treat.

I have reread initial post carefully, are we speaking about high priced custom blades here?

They don't.

They do. I have about dozen kilograms of different manufacturer catalogs and technical specifications at my home. Some of them specify blade hardness within 2 HRC range like SPYDERCO (59-60 HRC), some of them - within 3 HRC range like BENCHMADE (59-61 HRC). Some of them are specifying hardness with single value but in this case it is added about before this value, like in old KATZ KNIVES catalog.
Cold Steel with clear-cut hardness specification as in case of their Bushman knife (54 HRC) is rather rare exception.

Not very well mainly because it is a judgement...

It is just my personal experience, no way with any intention to be a judgement. I always have problem to consider when blade stops to shave, especially between two following cuts. So I always admire people who state: "This blade lost shaving ability after 57 cuts through the hemp rope and that one - after 58 cuts".