What’s just fine?

strahd71

strahd71

Joined
Jan 26, 2006
Messages
784
Sorry this is so long!

I have been reading all the posts about heat treating, and I have learned a lot, not enough but I’m a lot further than when I started actually reading the forums. I am now able to read Kevin Cashens posts on HT without getting a head ache. Do I still know what he’s talking about? No! But not from his lack of trying…. I’m just not that smart.

So at any rate I agree with him that the high dollar quenching oils are the best he makes a great case for them. I cant afford them nor can I justify them at this point because my knives aren’t good enough to warrant spending that kind of money. So Kevin I promise when I can I will buy the good stuff!

In all the posts other makers chime in and state that their method of quenching in everything from water, ATF, mineral oil, used motor oil, canola oil, vegetable oil, to tears of a virgin all “work just fine”.

What does this actually mean in the overall picture? There are guys out there making knives that cut through brass rods, chop down trees, shave the hair off a woman from north Dakota, but they are not using the “high dollar quenching oils”. How can this be if their using inferior quenchents?

It makes me wonder. I understand that the better quenching oils will get the most out of the blades with the right HT method. But if you take two identical blades same heat treat methods but quench one in parks or aaa oil and the other in mineral oil would there be that huge of a difference?

What would be the numerical difference on a scale of one to ten? One being poorest and ten being the best?

Its hard to understand it all. In actual performance how much do you really gain? Is there a difference in practical performance? Or is it all just theory?

I don’t know enough to have an opinion, but the information is somewhat confusing. There is no real consensus.

So what works just fine?

jake
 
I consider Mineral oil to be "just fine". The reason I say this is two fold.... first, if you track down the ingredients for most commercial quenching oils, you will find that they are 96-99% mineral oil. The additional ingredients to reach 100% consists of flame retardants, and/or wetting agents. Secondly, until very recently, I used Mineral oil exclusively for my quenching. As they say, the proof is in the pudding, and a most of those blades quenched in mineral oil have performed in the field for years, and several have even won cutting competitions.
The caveat is that everything else concerning the finish blade must be accomplished properly. You can use the "best" quenching oil in the world, but if the rest of the process isn't nailed down, its like putting a gold ring in a pig's snout.....its still a pig.

Realistically, anything that will cool steel at the proper rate can be used as a quench.....no quench oil (nor any other single aspect) will make a difference if the Overall Package isn't taken into consideration.
 
very true Ed.

It just seems like Heat treating has become almost as convoluted as our tax code. its sometimes hard for a newbie like me to figure out what is really necessary.

thanks

jake
 
Ed,

Just clicked on your link to the "Overall Package".......very interesting process. I like the succinct, yet thorough explanation of what makes a complete, well though out package of a knife. Almost makes me think of a flow diagram....ie, ask customer question (A) if answer is such and such follow on to appropriate part of diagram, and so on.
 
I think a lot of that depends on matching the steel to the quench. Mineral oil may quench some steels very well, but not necessarily others. No one shoe fits all, and of course that goes for commercial oils as well. Ed, I don't want to start anything, as I have great respect for you, and think you're a great maker with much knowledge and good advice to offer, but did I not just read a post of yours saying to always give the customer more than he expects? Would that not also hold true for heat treat? My goal has always been to give my customers the best I can. When I have not, it was due to ignorance, rather than lack of trying. I have gone in debt a number of times in order to upgrade, but I have always recovered my expeditures with increased, or improved quality production, in relatively short order, and I sleep better having more confidence in the quality of my work.
 
LRB: Yep! You did read that I always recommend giving the customer more than they expect....and that does extend to the heat treating. However, what must be understood is that just because an individual uses a commercial quench oil, that does not ensure the best heat treat. Assuming such a thing would be akin to thinking you could win every race because you have the fastest car.....theres a lot more to it than a single factor.
Your also correct that specific steels react more favorably to specific quenchants. I spoke in a generality, concerning the quenching, using my own little world of the steels that I consider "forgeable". (1080, 5160, 52100, etc). I know and understand that there is a wide variation of opinions about what quench to use, and am in no way making a blanket statement....just answering the initial question based on my opinions and experience. Commercial quenching oil is something nice to have, and certainly can make the job easier and less stressful, but it is not what makes the heat treat (although it is an important part), nor do I believe its a nessessity to produce a superior blade.
Thats what makes what we do so interesting....we each find our own combinations of methods and materials, to achieve a given end....meaning that there are no absolutes.....at least very few. ;)
 
It is Blade show time, but the other night my little girl wanted to do something and I told she shouldn’t since it wouldn’t work out the way she wanted, she of course asked “but why?” So I took the time out to explain the entire process in detail, step by step cause and effect and inevitable outcomes. I thought my job as a good dad was to save her some trouble, and give her some facts to work with in the future, and when I was done she simply looked up at me with those big blue eyes and once again asked “but why?” She had her heart set on doing things her way from the get go and thus had not heard a single word I had said. Smiling I just told her I had get back in the shop now, and she could proceed in any way she likes, life is all bout learning our own way.

Peoples thinking is quite convoluted but the quenching process is incredibly simple- make martensite by cooling fast enough to avoid any other phases without warping or blowing your blade apart. Here and other places one can find literally pages of facts about quenchants, and if that is still not enough to easily outweigh one-line platitudes about shaving North Dakota women or being “just fine”, then I don’t have enough time in my natural lifespan to combat that approach to fact finding.

Nobody owes it to me to use any product or method in their shop- THEY OWE IT TO THEMSELVES to use whatever best achieves the ends they have chosen. I have no interest in defining those ends or dictating how they should be achieved. The process is the actual reason we make these silly edged tools, why would I want to take that from anybody, or determine it for anybody else when I have more than I can handle doing it for myself?

So why do I type all my techno babble if I know the majority of folks making knives simply want to believe what they read in a magazine or online by their favorite big name?
Because I have a belief that a small percentage of people entering this forum for the first time hoping to make a knife will have different mindset and hunger for facts, and I strongly feel they deserve an alternative to the same old “do as I do, because it works just fine” approach.

If people want some factual tools a little deeper than “it works just fine” in determining what will work best for quenching carbon steels then go to the top of this forum and read the sticky that I already spent too much time on, although you are welcome. On the other hand if folks want to quench in 10W40 or goat urine, then do it already! Be happy and be proud! But Pete’s sake quit looking to me for positive or negative validation in that choice.

I have been short, I have been long winded, I have been gentle and I have been brutally blunt, I have also went through much trouble to lay out the process, cause and effect, step by step in order to put the facts on the table for anybody to use in navigating many of these topics. I believe I have tried about everything, but after all is said and done the follow up threads still contain the same flimsy points and counter points as if I had never said a word. I know many would be offended at having their words dismissed like background noise, but I honestly am not, I am just smiling as I say I have to get back in the shop now.
 
I feel your pain Jake, I really do appreciate the discussions on heat treating but it can be confusing, and some times taken to an extreme. The discussions have helped me focus more on the HT and make improvements. Those improvements have helped my customers and me as well. The thing that brings me back to earth is the picture of Ed Fowler standing in his shop heating a blade with a torch. I know the picture is old and he may have much different methods now, but, it does say there is room for simple methods in this complex world.
 
Kevin, you have taken the time - time and time again - to illustrate the benefits of using industry grade quenchants and the pitfalls and shortcomings of NOT using them.
And I thank you.
They are NOT expensive when you consider them one of the most significant items in the "recipe".
Just sell a knife or two and you'll have enough quenchant on hand to last years!
The people who design:
atf - think gears.
veg oil - think french fries.
motor oil - think internal combustion engines.
Mineral oil - the SINGLE MOST OFTEN used quality of mineral oil it to remove MAKE-UP!!!
And then, of course, a laxative.
Just get the right quenching oil and move on............
 
Can't we all appreciate the superb perfomance of ancient Japanese Samuri swords?

I believe it was my brother-in-law, with a MS in History, who shared with me the fact that many of these swords were quenched as they were ran through the body of live slaves and captives. Seems certain bladesmiths learned that the body temp. and chemical make-up of a human was perfect to achieve their goal of the perfect blade. I'm sure there was some kind of quasi-militaristic/religious aspect to it as well..... but gives us something to think about when considering the "perfect" quenchant. Just though I'd share that little tidbit of info.... :)
 
Japanese blades were not perfect. They may have been perfect for the Japanese' fighting methods, and for that time in history, but they were far from perfect. Their swords were not designed to chop, but to slice, and penetrate, which suits their close in combat tactics. Their edges are slightly on the brittle side in many cases, even though the spines may be soft. The Japanese developed their swords and methods over time to make the best of their smaller physical size. By the same token as you are judgeing the perfection of the Japanese sword, we should consider the Roman short sword as the greatest sword ever developed. Using that sword, they conquered the known world at that time. I have never understood the fascination with Japanese fighting blades, but to each his own.
 
dbalfa said:
Can't we all appreciate the superb perfomance of ancient Japanese Samuri swords?

I believe it was my brother-in-law, with a MS in History, who shared with me the fact that many of these swords were quenched as they were ran through the body of live slaves and captives. Seems certain bladesmiths learned that the body temp. and chemical make-up of a human was perfect to achieve their goal of the perfect blade. I'm sure there was some kind of quasi-militaristic/religious aspect to it as well..... but gives us something to think about when considering the "perfect" quenchant. Just though I'd share that little tidbit of info.... :)
Click to expand...

I don't care who has a MS in History this is just another silly romanticism

I love japanese swords I truly do, I've been studying their use for many years.
and their creation for a little over 5 years but I HATE how silly some people can be in their adoration of an object they don't even understand
 
I regularly see the quote that the best Japanese blades were run through the bodies of slaves or prisoners. This is pure junk, and I would like to see anyone (MS in history or not) prove it with any reliable historic text. It IS true that the blades were tested on bodies of prisoners being executed. The rating on body number ( one body, two body, etc.) is historically reliable, but was not a common testing method for most blades.

As to the great superiority of the quenching methods of Japanese samurai swordsmiths, If you want a blade that is mostly pearlite, about Rc45-50, and bends easily.....then by all means follow that procedure. If you want a 100% tempered martensite blade with a differential hardness from Rc50 spine to Rc 60 edge.....follow the metallurgist pros.
Stacy
 
Kevin, i hope you read the part in my post about where i agreed with you. this post and my question was not to antagonize you.

if it caused you frustration my apologies

jake
 
not to get any further side tracked but..... could you imagine the scale from quenching in a human body..... icky!

jake
 
I can't believe that anyone with a percentage of a clue would still believe the poppycock about quenching a sword in a human body. In addition to the cavitation effects which would cause uneven and partial hardening + warpage all on their own, there is the little issue of trying to quench a soft blade in a somewhat resistive medium (skin and flesh) that will likely writhe in agony before dying (even if you do not hit one of the randomly scattered hard obstacles called bone with your partially soft sword and bend your point right over)
Get a bone-in ham from your supermarket, allow it to come to body temperature and plunge a 1 foot long blade at critical temperature into it, measure your RC over the surface, I'm curious.

-Page
 
sunshadow said:
I can't believe that anyone with a percentage of a clue would still believe the poppycock about quenching a sword in a human body. In addition to the cavitation effects which would cause uneven and partial hardening + warpage all on their own, there is the little issue of trying to quench a soft blade in a somewhat resistive medium (skin and flesh) that will likely writhe in agony before dying (even if you do not hit one of the randomly scattered hard obstacles called bone with your partially soft sword and bend your point right over)
Get a bone-in ham from your supermarket, allow it to come to body temperature and plunge a 1 foot long blade at critical temperature into it, measure your RC over the surface, I'm curious.

-Page
Click to expand...


I'm roasting a turkey this weekend, I'd be willing to do it just for grins (4" blade though)
 
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