One-piece line hardness questions and concerns

I am not sure just what it is that you want to hear because the thread has gone around and around and the questions have been answered! There is no exotic reply that I can give you – the simple answer is that 55-57RC gives the most practical cutting edge for my one piece range. The angle at the cutting edge of our one piece knives is more acute than many large knives and this is one of the reasons why the knives cut so well. (Our knives are cutting tools, they are not pry bars.) The cutting edge is supported by the hollow grind which is done on an 8 inch wheel. This combines to give you the toughness and strength at the cutting edge that you need; the edge retention is good and the blade can be sharpened in the field. There has been comment that this is not much of a criteria but it is important to be able to field sharpen your knife.

Should any one feel that it is necessary to re-heat treat one of our fixed blades, Paul Bos is probably the best person to ask and he would do a good job. Remember though, your warranty would be voided.

We have been making these knives for over 18 years, they have proven themselves time and again, and in all parts of the globe. If I felt there was anything to be gained by changing the hardness, believe me, I would already have done so.

Chris
 
While I thank you Sir, it sounds as though I may have upset you. If so, I am sorry…but like a squeaky wheel, I would still like a bit more attention. Please bear in mind that I have tried my best to bring this up in as diplomatic and genuinely honest way as possible.

To that end, I do agree that one must be able to sharpen his/her knife in the field. That being said, there are many companies that make affordable diamond hones these days....unlike 18 years ago. With a diamond hone, a person can easily keep his RC60+ blade sharp and have the benefits of a longer wearing edge. The simple question I and other have raised is simply: "In your opinion, as the craftsman who knows more about these blades than anyone, will an RC60 A2 blade (on the Project II for example) suffer any negative consequences other than the need to use a diamond hone instead of a butcher's steel when it comes time to sharpen it?" In my opinion, based on the bulk of what we have seen here on this thread and others, the answer is a tentative "no." It appears that toughness will remain high even with this increase in hardness.

the edge retention is good and the blade can be sharpened in the field.
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I guess I am just wondering if edge retention could be better without suffereing any significant costs...

Further, I agree that this thread has gone on longer than it perhaps has needed to, but the fundamental questions that motivated it has still not been answered. I do not mean to sound argumentative, but I believe I have a valid question that is shared by many others. Also, I am not an armchair warrior who doesn’t even own a CRK blade…rather I own many of your products and use them both in the field and in many other situations. To say that "Chris Reeve Knives has been doing something for 18 plus years one way, so why change"...flies directly in the face of your efforts to stay at the cutting edge (no pun intended) of the folding knife market by constantly improving the steel and other aspects of your sebenzas.

Finally, I can surely appreciate the desire to “no fix what is not broken…” Indeed, I buy and use tomahawks from Two Hawks because his design, materials, and style combine to make a product that fuses the best there is to be had of both tradition and functionality. I am quite sure we can both agree that CRK has the same philosophy. Again, I didn’t start this intending for it to become an uncomfortable exchange…but it seems that it has. Until I receive a complete answer, I will read between the lines of your email and assume that you do believe that your knives are best left at RC55-57 so as to make sure their edges never chip out. Against your judgment, I have only a few reference tables and a healthy amount of skepticism to buttress my point of view. Therefore, I’ll yield to what I think you are implying and maintain my blade as is.

We have been making these knives for over 18 years, they have proven themselves time and again, and in all parts of the globe. If I felt there was anything to be gained by changing the hardness, believe me, I would already have done so.
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Indeed. My CRK blades have proven themselves time and time again...but Like Icarus, I will always be reaching for the sun....perhaps all my efforts will leave my knife to the same fate as he...but perhaps not. As I said, I'll lay down my wings on this one, but I will never stop looking for imporvements...
 
Chris, we are not upset but we are perplexed. You ask for an answer, we give it but you are not satisfied. You pose a question and then answer it yourself.

We do not do things today just because we started doing them that way 18 years ago – that is not what Chris said. What we do is evaluate our products constantly, and make changes as needed based on the experience of 18 years.

I don’t know how much reading between the lines you can do when there is nothing written between the lines. Our one piece range is built to be all round knives, capable of performing a multitude of tasks. The choice of the steel, the design of the blade, the geometry of the edge, the attention to the heat treatment process, the choice of hardness, the overall execution of the workmanship, all combine to make the knife what it is. The choice of Rockwell hardness is only a part of that make up, and it is only a part of the overall performance of the knife. Yes, there is a possibility that a blade at 60RC will chip - but it might not. A knife at 57RC could chip out – but it usually doesn’t. We cannot predict how every knife will perform under every set of circumstances - we can only take the knowledge available, the experiences we have and make our best judgment.

If feel that your knife will perform better if it were heat treated to 60RC, you are free to make that choice. However, we cannot be expected to support that knife if anything goes wrong with it. It might well be that nothing will go wrong with it – we don’t know for sure. What is for sure is that if your knife, as it came from our shop, were to break, chip, whatever, we will stand right behind it.

Anne
 
I wish to represent some of the users of CRK One Piece Knives, those in the military, and speak directly to the issue of sharpening. "Warriorsociologist" brings up the point that the use of harder premium steels should pose no problem to the user since diamond hones can handle sharpening these steels. The problem is that knife sharpening is still an acquired art amongst soldiers. Few have the knowledge or skill to sharpen anything correctly and sharpeners are usually an afterthought. There are more small stones out amongst the troops used to sharpen knives than diamond. These concepts haven't caught up with them yet. Just because someone buys a premium knife doesn't mean they have a premium sharpener, or know how to sharpen at all!

It is more likely that a troop with a dull knife will find a buddy with a stone than a diamond sharpener. ...and "steeling" a very dull knife is worthless.

Until sharpeners and sharpening are common out with the troops, a more easily sharpened knife is still the answer.

Bruce Woodbury
 
Well...what I had most feared has happened. Even though I thought I made it very clear that I was trying to be objective about this, I have somehow managed to steer this into an argument... For that I am sorry. However, perhaps the risk was worth it…only time will tell.

To be clear, I have never said that I am unhappy with my knife. I do however think that a seemingly obvious improvement to it could be to make it a little harder. Anne, I know that your knives are:
built to be all round knives, capable of performing a multitude of tasks.
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...believe me, I do. I just thought that they could possibly still be all of this and more while being hardened a bit more. Recall that the reason this thread was started was that some sources suggested that A2 has the same toughness at RC57 and at RC60. Based only on that piece of information and the obvious fact that a harder edge will wear longer, I posed this question.

Since your experience and mine both suggest that your knives are suburb performers, I have not, nor will I dispute that. It just seems to me that the entire battery of responses to the questions that have been raised about hardness sound overall very defensive. I can tell for sure that I am not attacking your way of doing things...I am only asking a question. Still, the only reason I have seen anyone give for why you keep your knives at RC55-57 is that it is the status quo...”why change what works.” To me, the only reason to change “what works” is if change will make “it” work better. To me it seems strange for the same company who passionately pursues the most current steel alloys for their folders, invests in new heat treatment techniques, and such....to only reply with "we just don't want to change because we don't want to change" when asked about other possible improvements to their other products.

Finally, this whole experience has made me wish I had just asked this question over the phone... Had I done so, I would not have been painted as "the bad guy" as it seems I have been here. I posted this question here, in public, because I felt that many others also were wondering about it as well. If I have some how offended you or other CRK fans because I dared ask this question, I guess I’ll bear the burden of doing so. To me, asking questions of manufacturers and fellow users in an open public forum is exactly this place is all about.

I will not reply again to this thread - to do so would, I feel, only stir the pot even more. I think what can be learned from it is abundantly clear now...even if it is not the type of information that I had originally intended it to bring out. I will continue to use your knives, as they are, in silence. After all, they are still the best available. Will they perform? Of course! Could they perform better if they were harder? Who knows...I know I will not risk my personal blade to answer such a question. Maybe someday, someone will.



[EDIT]:

Ok, I lied...sort of (about not posting again). I have found a nice (but old) explicit statement regarding the trade-offs between RC57 and RC60. This gets straight at the "why" behind CRK's choice of keeping their knives at RC55-57:

Chad, your review is interesting and informative. We appreciate the many compliments that you give us!!

There is a technicality upon which we want to elaborate and that is your comment about heat treatment. You say The heat treat strategy that Reeve has adapted is somewhat unusual, he is running his A2 at 55-57RC, whereas other makers typically run A2 at 60RC. In A2 this reduction in hardness does not generate any additional toughness and results in a loss of strength.

You quote Crucible's Charpy C-notch statistics on A2 that show the identical toughness results at 57 RC and 60 RC i.e. 41 ft.-lbs (56 Joules). Chris' choice of 55-57 RC for all the fixed blades provides the optimum balance between toughness, shock absorbency and edge retention. While 60RC might result in a knife that keeps its edge for a longer period, it is extremely difficult to restore that edge in the field. In Chris' opinion, this period of edge retention is not significantly longer to warrant the downside of extra effort in sharpening, especially when there is no loss in toughness.

For over 18 years, these fixed blade knives have proven themselves over and over again. Because our knives are mostly multi-purpose, Chris pursues the philosophy that the best kind of knife is the one that excels in the majority of requirements - these include aesthetics, ergonomics, geometry, edge retention, toughness, hardness and execution.

I hope a little CRK philosophy helps you understand our position!

Anne
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From: http://www.knifeforums.com/ubbthrea...184237&page=0&view=collapsed&sb=5&o=7&fpart=1

While much of this has been repeated above, this old post speaks directly to my questions & concerns. Thanks Anne!

:)
 
Originally posted by bruce
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...Just because someone buys a premium knife doesn't mean they have a premium sharpener, or know how to sharpen at all!
For someone who doesn't konw how to sharpen it doesn't matter whether the knive is easy to sharpen or not. May be harder blade will last them coulpe days longer :)

It is more likely that a troop with a dull knife will find a buddy with a stone than a diamond sharpener.
Stones are just fine to sharpen A2 or whatever else too. May take longer but that's not all that difficult either. In short diamond stones are not the only thing that can sharpen A2 at 60HRC. So, the issue is rather sharpening skills than the equipment.
And IMHO for inexperienced user it's easier to screw up the edge with diamonds than with the stone ;)
 
Re heat treat or leave as it is- stop playing "Hamlet", do what makes you happy, and just enjoy the knife! :)
 
Not trying to be argumentative in this late post, either.

Numerous makers who use A2 in any amount tend to head for Rc60. Kinda doubt that is accidental, somehow, but I'm not a maker.

Examples:
RJ Martin
Phill Hartsfield
James Piorek

Dozier tends to run it up to Rc60 also I believe, just like he does D2 (Rc61).

If you are lucky, RJ might chime in. He's not dogmatic at all, and seems to be quite practical and engineering-like in his approach and attitudes.

Others have pointed out that Crucible's quantitative Charpy toughness metrics probably apply more aptly to metal left in thicker cross section than a knife blade, and that the toughness "curve" for A2 in Crucible's illustration might be misleading when it comes to any given knife (paraphrasing Hossum from memory, verifiable via search engine).

At this stage, I'd be in favor of letting a pro like Paul Bos run a heat treating experiment for you if you think it's worth the money and very slight risk to bead blast the black Kalguard and have the knife re-treated. I'd say go for it, but it's not my knife and my risk is close to zero for me :D .

I agree that given the one piece of this CRK knife, you are unlikely to run into any thermal expansion/contraction or cracking issues, especially in the hands of "The Heat Treating Man", Paul Bos. A2 is apparently relatively easy to heat treat in the scheme of all things knife-like. A "lay up" for Bos, I'd guess.

Better still, buy an identical knife from Reeve and leave at Rc55-57, have the other treated by Bos to Rc60, and compare the two as objectively as you can. Or send them both to Cliff :D ;)
 
Gator97, the troops don't have diamond sharpeners and little sharpening skill. They are better served by having knives they can sharpen with the tools available and with their current skill levels. With harder knives, stones, and little skill, they will only get frustrated.
 
I think we need to put this trivial matter to rest and move on to the more important question about the fix blade line:
TO BE 3V, OR NOT TO BE 3V?
:)
 
No earth shattering revelations here, even though it seems that's what some of you guys are looking for. Here's a point from my personal experience, though. I've had A2 knives from some of the above mentioned makers chip and have had others that wouldn't cut through a zip-tie without the edge deforming. Go figure. BTW, the blade that chipped the worst supposedly had an "armor piercing" tip which broke off piercing a piece of ballistic nylon.

Unlike some of the others, my one piece knives have been extremely consistent. Great performers all the way around that you can count on to take a severe beating without failing, if it ever came to that. Guys, you can trust these knives. The same cannot be said for many others out there, some costing many times more $$. I've been carrying and using these knives in the outdoors for the past 6 years or so, I trust the knives explicitly and I would NOT want to see CRK change a darn thing with the one piece line.

Pete
 
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