Quench Wars! -- Side-by-side quench test

[Kevin R. Cashen]

Let me continue with my line of thought concerning testing and results. I actually like these results because they make us stop and go “what the @#!$?” That is a good test! The best tests always produce 10 times more questions than they do answers. When I do a test, I am always disappointed in predictable results. Testing is for finding the unexpected or shortcomings that can be improved upon, tests that only confirm our claims and beliefs is called marketing , and the majority of the “tests” you read about in magazines is exactly that. So this test is good, it surprises folks and makes us reconsider our conclusions.

Now the next step, which can be even harder than the initial work is carefully and properly interpreting the results. Most of this is trouble shooting the data, which is easier with as few variables as possible, the bad news is that this exorcise involves too many to count. It is in the interpretation of the results that most misinformation in the bladesmithing field has been born. That is why it can be so touchy correcting that information without people feeling that you are questioning their honesty. Heck they saw the results with their own two eyes, are you calling them a liar? Unfortunately coming to a reasonable conclusion based upon the observed evidence can be completely sincere and honest, and still be totally wrong. This is why tests that shake up your preconceived notions are the best, they keep us looking at all possibilities without becoming complacent, or relying on assumptions.

In interpreting the results, assumption is the most dangerous pitfall, and it is why keeping our mind clear of predictions of outcome before interpreting the data can be very important. Does this sound patently obvious to folks? Well consider this- how many reading these results had second thoughts about the effectiveness of MacMaster Carr oil, but at the same time automatically assumed there had to be an error in the readings from water? After all, we all know that water is the fastest of those quenchants (I can assure you that P #50 is fast but it does not beat water), but none of these results must to be incorrect any more than they must be correct. The proper way to approach the interpretation would be as if we had never heard of, or knew anything about, any of the liquids used, including water, and then start deconstructing things by considering the properties involved.

If you think this is tough, I actually do heat treating consulting for some production companies, just try to work out over the telephone what could be going on when steel decides to defy the very laws of physics in a heat treating quirk. The only way out of that morass is to examine and record every approach, change just one variable at a time, re-examine the results for any effects and then move to the next variable. Often the answer will reside in a factor so far removed from the area on which you are focusing that you realize that everything within the sphere of existence of that steel must be considered since time didn’t start and stop just during the operation in question but continued to effect the outcome on every subsequent test.

Variables, variable, variables… so long as there are variables, easy answers are a pipe dream.

 

[LRB]

Kevin, you are truly a treasure to those of us that appreciate what you do by sharing your time and info. Take care, and please keep it up.

 

[McClellan Made Blades]

Kevin, you are truly a treasure to those of us that appreciate what you do by sharing your time and info. Take care, and please keep it up.

I second that, We are ALL busy, Kev is probably busier than most, but he takes his time to help those with lesser knowledge, I guess what we're trying to say is THANK YOU!!! That isn't enough, but it's the best I have right now. When I can I will show you how much I appreciate all you do. And PLEASE do keep on sharing because without your help, I know a lot of folks would be lost, me for one!

 

[Kevin R. Cashen]

... We are ALL busy, Kev is probably busier than most, but he takes his time to help...

I am actually so busy right now that typing on this forum was a stress relieving 10 minute break. I have been hunched over a dagger pommel for 3 days now staring at the metal carvings through the optivisor until I can now no longer feel the end of the finger that was guiding the tools, so forgive the extra typos. I have my doubts that most of that last post will be helpful to many other than myself for changing gears in my thought process for a bit.

And, as always, you are most welcome. So long as people are willing to talk about all of these concepts and keep the learning moving forward for all involved, especially myself, I will be happy to help out or just chat.

 

[Kevin R. Cashen]

... I beg you gentlemen to embrace the results in the same informal spirit. Many people read things on these forums and take them quite seriously and the results you present could greatly influence decisions people make, there may be responsibility with that. Not that I am raining on your parade, I keep many of my own findings for my own consumption simply because I want to be certain they are error free before going public, and I am too neurotic to ever reach that point...

I am not psychic, but I have almost made a career of tracing the origins of misconceptions in the knifemaking business. There are now people abandoning McMaster Carr oil as if any results from this exercise could be considered conclusive. Rusty and Darrin have made a great start down the road of finding some answers about quenchants, but with this test they are still leaving their driveway on a very, VERY long journey.

Folks, I am not abandoning Parks #50 for fear of cracking since this thread shows it is faster than water, nor would I abandon 1084 for 1090 due to it showing higher hardness from the baseline of water, since it is a fact that 1090 is perhaps the shallowest hardening of high carbon 10XX steels. The same would apply to the McMaster Carr numbers.

Have you ever, hesitated to show somebody your knife before it was finished because you knew that half done it would in no way resemble the finished product and you wanted the only image people had of it to be when it was complete? Test results are even more like this. To make any decisions about your methods based in this thread is very unfair to Darrin and Rusty, and damaging to bladesmithing as a whole.

In my first post in this thread I was trying as hard as I could to be gentle, but I posted because I saw the potential danger in this thread. Bladesmithing will be decades repairing the damage, if it ever fully recovers, when guys with access to space in the printed magazines publish results of their "testing" (I use the word VERY loosely concerning the Mags) without due consideration of the whole picture, and Rusty and Darrin made a heck of a lot better attempt at an actual study than much of that stuff.

Please, Please, Please view this thread as just scratching the surface enough to create the questions we need to prompt a deeper look at the subject, as that is the only way to allow it to contribute to our knowledge and not become one more pile of bad information that could take years to overcome.

 

[McClellan Made Blades]

I am not psychic, but I have almost made a career of tracing the origins of misconceptions in the knifemaking business. There are now people abandoning McMaster Carr oil as if any results from this exercise could be considered conclusive. Rusty and Darrin have made a great start down the road of finding some answers about quenchants, but with this test they are still leaving their driveway on a very, VERY long journey.

Folks, I am not abandoning Parks #50 for fear of cracking since this thread shows it is faster than water, nor would I abandon 1084 for 1090 due to it showing higher hardness from the baseline of water, since it is a fact that 1090 is perhaps the shallowest hardening of high carbon 10XX steels. The same would apply to the McMaster Carr numbers.

Have you ever, hesitated to show somebody your knife before it was finished because you knew that half done it would in no way resemble the finished product and you wanted the only image people had of it to be when it was complete? Test results are even more like this. To make any decisions about your methods based in this thread is very unfair to Darrin and Rusty, and damaging to bladesmithing as a whole.

In my first post in this thread I was trying as hard as I could to be gentle, but I posted because I saw the potential danger in this thread. Bladesmithing will be decades repairing the damage, if it ever fully recovers, when guys with access to space in the printed magazines publish results of their "testing" (I use the word VERY loosely concerning the Mags) without due consideration of the whole picture, and Rusty and Darrin made a heck of a lot better attempt at an actual study than much of that stuff.

Please, Please, Please view this thread as just scratching the surface enough to create the questions we need to prompt a deeper look at the subject, as that is the only way to allow it to contribute to our knowledge and not become one more pile of bad information that could take years to overcome.

Very well put Kevin,
I'm no master of anything in the knife making world, but I have to rely a little on my own experiences. The Mcmaster Carr quench has done me very well, through my own testing I have found that my blades hold up to what could be considered as abuse, there are so many variables when ht'ing steel, as someone else stated the temp the steel was taken to, being just one. I'm not knocking the guys that spent their money and their time to do this test, matter of fact my hat is off to them, and I would say keep up the good work! They didn't post their results to make anyone feel bad or good, I believe they posted the results they got, even if some folks don't agree with them. I admit I was ready to abandon the McMaster Carr quench oil, funny thing is I had just re-ordered 2 more gallons right before this test was started. I've always gotten great results, I've alwys been more than happy with how my blades turn out, so if it works, why change? On the other side of it, I don't have to deal with a company that really doesn't want my money. I know, I called them myself, and got the usual response they tell everyone, "they don't sell to the public", like they are too busy to sell me 5 gallons, or that I'm just not important enough. They did refer me to one of the places that they said does sell it to the public but when I called them they told me they didn't. I would also like to point out there is another quenchant that was left out of the test, Houghton, from Brownell's, it runs about the same price as McMaster Carr, and works pretty well from what I've heard from other makers that use it. Take the test for what it's worth, but don't abandon what you already KNOW. And again the fellas that did the test, THANK YOU!!! Rex

 

[Shane Wink]

I know this thread has been dormant for a few months now but has anyone posted some thoughts on how the results ended as they did? I am no one at all and I am not stating anything but rather I am asking. From information that other Knowledgeable ppl have posted in the past do the results point to the formation of a vapor barrier between the steel and quenchant slowing the cooling process? Was agitation used in the quench tank and agitation of the pieces being quenched?

I ask these things in an effort to try and learn and again I am not saying this is the cause.

 

[LRB]

I think you are wasting your time. You need more than a hardness tester to see the true results. You need high tech stuff like Kevin has. Hardness is not the full story on the quality of a heat treat, and if hardness alone is what you're going for, you're gunna have to test multiple times in different areas of the steel to see what you have. You will not be the first to run such tests, and I would bet a phone call to Kevin would save you the trouble. I also think you should include brine in these tests.

 

[Kevin R. Cashen]

I am treading lightly here, since my concerns for the interpretation of results already has me behaving like a bull in a china shop here. Rockwell tests are wonderful things in that they can be done by anybody. The Rockwell method was developed to eliminate human error through direct reading as opposed to other hardness tests that rely on the human eye measuring the size of an impression in a middle step of the procedure.

I would be confident that the Rc readings are what they are, but the one thing that the Rc tester cannot tell you is why the readings are what they are, and it is in the attempts to interpret that “why” that the door is opened for trouble. The samples are what they are, they will each have properties and characteristics that are now set in stone and are undeniable, it is the history leading up to their current condition that is the key to the questions. I cannot say it enough that quenching is one of the most incredibly complex operations we deal with in processing steel and totally understanding it could require more time and effort that most of us may have to give. There is not enough bandwidth available to cover all the possible variables in the process leading to the results.

My input couldn’t differ much from what already has been. High tech, or anything in my shop is no more effective than a file without the missing pieces in the history of the process. I could find pearlite in many places, but all it means is there is pearlite there, it is finding out exactly why it is there that is the real trick and unfortunately even the microscope can’t see through time.:3:

 

[gnique]

This question may not be germane to this experiment but I still would like to be informed about a process that was done during preparation of the steel coupons. It looks to me like that the steel that was used is just plane ole flat stock steel. Other than cutting coupons and drilling holes no cutting, grinding or shaping was done - is that not right? Why then were the coupons normalized? I don't see the reason for this step. Isn't the only reason for normaization is to relieve induced stresses due to forging, grinding, etc? If unworked factory flat stock was used for the test why normalize? I am NOT criticizing I am just asking a question. My intent is to understand as much about the results of this test as I possibly can. I really do believe what Kevin said earlier. This stuff needs to be thought about and understood in a real and rational way otherwise we risk generating more myths and false "facts". Thank you for doing all this work. It is much appreciated by us all. I think that the best way that we can SHOW our appreciation is to delve as deeply as we can into the results. Sincerely - Nicholas Jasper

 

[Darrin Sanders]

Finally found someone locally with a hardness tester who was willing to test some stuff for me. Keep in mind that these results are for MY H/T process using MY kiln and MY oil. Other peoples results may/will vary. Pieces were blade size pieces with no bevels ground, they were profiled only to keep them flat for testing purposes. The steel used was 3/32" CRA 1095 from Admiral. The oil used was Mcmaster-Carr 11 second oil. My quench tank is a large electric roaster and the oil was at 125 deg. at the time of the quench. The test pieces were brought to 1475 deg. and soaked for 5 min. then quenched. It may also be worth noting that my quench tank is immediately in front of and just below the front of my kiln. This allows me to go from kiln to quench in less than a second. Ok here are the results.
Piece #1 tested as quenched HRC=67 in three different spots.
Piece #2 tested after a 425 degree double temper=HRC 62-63.
I was pleased with the results. I intentionally tempered on the low side in case as quenched hardness was a little low. From now on I think I will temper at 450-500 depending on desired hardness and intended use of the blade. I'm a whole lot more comfortable using the 11 sec. oil now that I have test results from my own H/T process. Everyone please feel free to comment or ask questions if I left anything out.
Thanks, Darrin.

 

[McClellan Made Blades]

Darin,
These are the type of tests we need! Great job! I've been using McMaster Carr 11sec oil for a year now, although I haven't done any extreme testing I've been pleased with my results, my customers, as well, are very pleased with the way my knives have performed for them.
Big question, once you put the steel in the quench, did you agitate it vigorously? I believe that agitation is the key to the rapid cooling needed to get the hardness we're looking for. As Kevin has said it breaks up the vapor jacket created once the hot steel enters the liquid.

I'm excited about the developments with Maxim Oil, I still feel like we need a faster oil for 1095/1084/W2, and as Kevin has stated 1095 requires a 6 to 9 second oil, (see Kevin, we are learning, albeit slow, you are making a huge impact in our understanding of metallurgy, and for that I say THANK YOU!!!) My faith in McMaster Carr never wavered, the only thing I questioned was the speed, I knew that I didn't want to give my hard earned money to a company that doesn't value us small guys, I called Heatbath myself, they gave me the usual spiel they give to folks that aren't going to buy a train load of their quench, while it may be the best out there, or at least the most widely used by knife makers, I can't fathom the notion to buy it when they don't care about my business. Even if I can get it from other sources, "it just don't set right with me."
Darin, keep up the good work, your numbers look really good, I would like to see some results on some thicker 1095 and 1084, I tend to make bigger knives, choppers and such. Just like the late GREAT Bill Moran said when asked, "Why do you carry such a big knife?", his reply,
"Because their FUN!" Thanks Rex

 

[Darrin Sanders]

Hey Rex, like you, me and my customers have been pleased with my 1095 blades quenched with Mcmaster-Carr oil. Now I have a little data to reinforce my confidence. To answer your question about agitation, yes I move the blade in a fore and aft motion and also a little up and down motion too. Anything but side to side. I too think this is very important. I also agree with you about my money going to a business that appreciates it and I believe Mcmaster-Carr does. I think they provide a readily available product at a reasonable price that works well with the majority of steels used by knifemakers. Now that I have access to a hardness tester I intend to test other thicknesses of 1095. I started with 3/32" because no matter what thickness the spine is these results should show that it will harden far enough up the blade to make a serviceable knife. At least I hope I'm right. I still have more questions than answers but I will continue to test and show results as they are available. And I do appreciate all legitimate questions and gainful input. To me knifemaking is 99% about H/T and performance and I'm trying to learn as much as I can. I keep my mind, eyes, and ears open as I try to educate myself in this area. Thanks Rex, Darrin.

 

[Kevin R. Cashen]

Darin,
These are the type of tests we need! Great job! I've been using McMaster Carr 11sec oil for a year now, although I haven't done any extreme testing I've been pleased with my results, my customers, as well, are very pleased with the way my knives have performed for them.
Big question, once you put the steel in the quench, did you agitate it vigorously? I believe that agitation is the key to the rapid cooling needed to get the hardness we're looking for. As Kevin has said it breaks up the vapor jacket created once the hot steel enters the liquid.

...(see Kevin, we are learning, albeit slow, you are making a huge impact in our understanding of metallurgy, and for that I say THANK YOU!!!) ...

...when asked, "Why do you carry such a big knife?", his reply,
"Because their FUN!" Thanks Rex

No Rex, thank you! Your kind words are greatly appreciated and are the payment that keeps me going in my efforts to share. But I cannot stress enough that my sincerest hopes are that information I provide lights enough fires under people to get them all researching on their own, especially to verify if I and others actually know anything we are talking about. My favorite people are the ones who start reading metallurgy books to see if I am just full of @#$%, they are independent thinkers who keep me on my toes, confirm the sound principles I work with, and usually become good friends. We don’t need yet another school of blind recipe followers, and the future of our craft looks exciting with all the people gathering sound facts with which to write their own recipes.

P.S. Fun is indeed the best reason to carry a big knife, or even forge them. I think bladesmiths are wired different about “fun” though. I just spent and entire day looking through a microscope at parts of another microscope to insure my cleaning is leaving all the optics in my metallograph immaculate and dust free so that I can have fun looking at the inside of the blades, heck I even found cleaning the thing kind of fun… to be honest bladesmiths really aren’t all right in the head.

 

[McClellan Made Blades]

No Rex, thank you! Your kind words are greatly appreciated and are the payment that keeps me going in my efforts to share. But I cannot stress enough that my sincerest hopes are that information I provide lights enough fires under people to get them all researching on their own, especially to verify if I and others actually know anything we are talking about. My favorite people are the ones who start reading metallurgy books to see if I am just full of @#$%, they are independent thinkers who keep me on my toes, confirm the sound principles I work with, and usually become good friends. We don’t need yet another school of blind recipe followers, and the future of our craft looks exciting with all the people gathering sound facts with which to write their own recipes.

P.S. Fun is indeed the best reason to carry a big knife, or even forge them. I think bladesmiths are wired different about “fun” though. I just spent and entire day looking through a microscope at parts of another microscope to insure my cleaning is leaving all the optics in my metallograph immaculate and dust free so that I can have fun looking at the inside of the blades, heck I even found cleaning the thing kind of fun… to be honest bladesmiths really aren’t all right in the head.

Kevin,
I was looking at some metallurgy books the other day, but it's difficult to choose which one would be a good one that would have information that would pertain to knifemaking, can you give us some suggestions? I know you've mentioned one before, but I don't recall it. I'm sure there aren't any that are specific about knifemaking, maybe you need to write that book??? Huh, Idea?

As far as bladesmiths being right in the head, I think that 2 of the requirements are that you must NOT be right in the head and you must be the best of the good people in the world!

Hope you got your optics straight, nothing more frustrating than a dirty lens, when your working on something you need to see NOW!

I must point out that all the Thanks in the world is owed to you, the amount of time and effort you take to explain the details is enormous. The least we can do is try to understand and (for me) possibly learn some of it. So thanks goes all to you, Rex