1084 quenching, just the blade?

[Rick Marchand]

... My mind is doing some funny stuff with the text today, lines repeat, disappear, mouse not responding when I talk to it. That last "iced tea" was way too hard. I guess I must need some sleep time... I threw up.

There Buddy, fixed it for ya.

 

[AVigil]

I learned a lot from this thread. Thanks guys

 

[woodwrkr221]

-I-used-my-knife-to-change-a-wheel-bearing"]knife to remove a fused bearing race[/URL] was the most logical approach?

Rick

Isn't that what machine shops are for? Oh wait, I forgot, you were on top of Mt. McKinley.

 

[Rick Marchand]

Isn't that what machine shops are for? Oh wait, I forgot, you were on top of Mt. McKinley.

Ha! Nice.:thumbup: The alternative would have been to drive to the nearest stop to call a flatbed tow truck to haul it to the closest garage which at 4-5pm wouldn't have gotten to it until the next day..... if I was lucky.

 

[Ed Fowler]

Good point Salem and I am pleased you asked: the tangs on my knives are dead soft, with the striations I put in the tang for an epoxy bond I can bend my tangs a full 180 and then forged the tail down to the spine without it breaking. I have drilled holes at the request of a client who wanted "hidden pins". To make sure it did not create a catastrophic failure probability, I was able to bend it to a sharp 90 before the steel started to tear above and below the hole, but it did not break.

Along the same line, years ago a forged blade handle came off during a demonstration. The hue and cry was heard for pinned handles to keep them from coming apart and injuring a bystander. There was no mention of soft tangs. One man who participated brought his knife to me for "testing of handle attachment strength". First we tried to beat the handle off and could not, then we tried to pull it off using a clamp, vice and come along, could not pull the handle off then we ground off 1/2 of the handle to reveal that his pins did not pass through the tang!!!

You will only know what your knives can due when you personally test them to destruction. There is no substitute or theory that can take the place of personal experience.

 

[Tai Goo]

There Buddy, fixed it for ya.

Gee thanks Rick. How can I ever repay you?

 

[sunshadow]

Regardless of what Mr. Fowler says, metallurgically you are much better off doing the full heat treat on the whole blade INCLUDING the tang which will give you uniform structure and grain size and carbon distribution throughout, as well as giving you optimum strength, then temper back to your desired edge hardness over the entire blade, and draw your tang back to a spring temper. By doing that you will avoid excessive localized carbide growth which can act as a stress riser, as well as pearlite precipitation which often happens when a tang is forged out and left dead soft (and also typically happens in the cloudy areas of Hamon)

-Page

 

[Salem Straub]

Thanks for responding there, Ed. By the way, I truly enjoyed Knife talk I&II.

I know there's a lot of disagreement over variable HT methods. I don't see it necessarily as a "which is better" contest, I see it more as a "which fits my philosophy of use better" question. Some like more stiffness, some like a blade that will bend and take a set but be very unlikely to crack. Either is good. Just as long as a smith has valid methods to achieve his ends, and is transparent with his customers about what they are and will achieve.

Page, I'm pretty much there with you.

 

[Tai Goo]

I know there's a lot of disagreement over variable HT methods. I don't see it necessarily as a "which is better" contest, I see it more as a "which fits my philosophy of use better" question.

There is no substitute or theory that can take the place of personal experience.

Very true guys.

Metallurgy isn't the rule, it's just a tool.

Heat treating isn't about what is correct or incorrect, it's just a way to manipulate and modify the properties of the steel. There is no such thing as metallurgically correct (outside of the text books) or metallurgically better. When it comes to knives, we really are talking more about personal philosophy and preferences than any concrete or absolute science.

Don't be fooled by those who are pushing the "scientifically correct knife" myth. There is no such thing.

 

[Tai Goo]

... The heart of the matter isn’t whether a hard tang or soft tang is better or worse, it’s whether you can do either one or both (or anything in between) to suit your personal desires, and understand the differences.

There are advantages and disadvantages to any and all of it.

In some cases, "for all practical purposes”, it may not make any difference either way. In other cases, it may make a huge difference. The important thing is to learn about all of it, when to apply what, where, and why.

 

[Rick Marchand]

There is no substitute or theory that can take the place of personal experience.

Yes, there is. Your personal experience is... well, personal. Too many variables to count. I could tell you that making swords out of old leaf springs is a bad idea because it is difficult to know whether or not there are pre-existing stress fractures from overuse. You may have made a sword out of one before and had no problems but that doesn't negate the fact that blades have fallen apart due to this exact reason. If we simply went by personal experience, imagine all the time and energy that would be waisted on the likelyhood of discovering something that others have already proven. "Theories" of metallurgy aren't just plucked out of the air... they come from experience, too. The only difference is that metallurgical science has been challenged, peer reviewed and time tested. All these "myths" that Ed himself has written about (ie. edge packing) where eventually dismissed by the knifemaking world. This is a good thing but the fact remains that they were proven wrong by modern metallurgy loooooooong before that. The bladesmithing world needs to catch up with the rest of the folks who live in the present.

Very true guys.

Metallurgy isn't the rule, it's just a tool.

Heat treating isn't about what is correct or incorrect, it's just a way to manipulate and modify the properties of the steel. There is no such thing as metallurgically correct (outside of the text books) or metallurgically better. When it comes to knives, we really are talking more about personal philosophy and preferences than any concrete or absolute science.

Don't be fooled by those who are pushing the "scientifically correct knife" myth. There is no such thing.

... The heart of the matter isn’t whether a hard tang or soft tang is better or worse, it’s whether you can do either one or both (or anything in between) to suit your personal desires, and understand the differences.

There are advantages and disadvantages to any and all of it.

In Tai's defence(not that he is asking for it) it doesn't mean that you shouldn't make a blade in a traditional Japanese fashion. It is not WRONG to do that... it is a choice. However, to claim that it is superior to modern steel and heat treating methods, is where it becomes a right/wrong thing. Those smiths of old did the very best they could with the knowledge they posessed at the time... real ground breaking stuff... but if you went back to that period and handed Gorō Masamune a well made L6 sword, fashioned through sound metallurgical "theory".... a few tatami mat rolls and condemned criminal volunteers later.... I'm willing to bet he would be crappin his kimono.

I see it like this. Gravity is a theory, too. It is just a tool you can use to get from a raised platform to the ground. You can go further to say that there is no right or wrong way to use gravity to accomplish this task. Some folks can jump straight to their feet and others tuck and roll. But there is a definite science to it that can be applied.(some mistakingly label it as art but art is just applied science in essence.) Approach angles, body positioning, strength and flexibility training all come into play. There is a optimal way to jump from a raised platform to the ground.

Tai you seem to play off metallurgy as a new "fad" but it has been an integral part of your artistic approach all along... we are just aware of it now. Like gravity, you cannot change the fact that metal transforms as you apply heat to it. Like gravity, it is bound by universal law to behave exactly the same way, everytime.

Don't be fooled by those who are pushing the "scientifically correct knife" myth. There is no such thing.

At first, I was frustrated by this statement.... but the more I read it the more I understood what you are saying(at least I hope that I did). I don't think there is a "scientifically correct knife" but there are scientifically accurate ways of making any given individual's notion of the perfect knife. Art is the human factor in interpreting and using universal science.

or I could be wrong....

Rick

 

[Ed Fowler]

Page: I would ask the following questions of you.

How do you know these things happen?
What is the intended purpose of your knives?
How do you test your knives?

These are questions I have been asking of myself since I started making knives.

 

[Rick Marchand]

Page: I would ask the following questions of you.

How do you know these things happen?
What is the intended purpose of your knives?
How do you test your knives?

These are questions I have been asking of myself since I started making knives.

Ed how do you personally prove that the Earth orbits the Sun? You are not equiped to do so, but fully accept scientific "theory" as it has been shown to you. Obviously, at some point, it seemed reasonable for you to believe it without ever having done your own testing. Same goes for metallurgy. We have these wonderful people in white coats who have actually documented, photographed and otherwise proven these metallurgical phase transformations to be real and predictable.

Rick

 

[Tai Goo]

Rick, no I don't think metallurgy is anything new, not at all, but in do think there are "trends" in knifemaking based upon certain types of logic and applications of science. Certain parameters are set by individuals to make the logic sound good, but if you change the parameters the logic no longer applies.

In Ed’s defense, his study of text book metallurgy would also fall under the heading of “personal experience“. Text book study is part of personal experience.

Testing things for yourself is about as scientific as it gets. However, If we just take someone else’s word for things and don’t do some experimenting to see for ourselves, we leave the science to someone else. That’s not doing science.

The problem with the so called scientific “approach” is that it leaves no room for science. Instead, it just pays someone else to do the science for you. What fun is that?

 

[Rick Marchand]

I wasn't trying to say that you felt metallurgy was new... I would never take you for a fool, bud. I simply felt that perhaps you felt the "fad/cult" of metallurgy was something recent. I agree that some people use metallurgical science poorly(I am probably guilty of that often enough) It is easy to twist what seems scientifically sound, to suit your agenda.(see "confirmatory bias")

Hell, lets just make knives and stop worrying about the details. Eventually, they will sort themselves out if one truly desires to improve their craft. Your blades have always sang to me, Tai.... which is why you can see their influence in my own work. These conversations are necessary because in the end, we all want to make a good knife..... I hope.

Rick

 

[Tai Goo]

O.K.

But just for the records, I don't think Ed has ever said, "just take my word for it", but rather, "try it for yourself and see". To me, that's very scientific.

 

[Rick Marchand]

By definition, yes it is.

*ETA*
Studying the Sun for a month and documenting how it passes from East to West is also scientific. With that study, one could conclude that the Sun orbits the Earth. Right or wrong, it is a scientific approach. Personal experience is only one part of finding truth. In this instance, a little reading and trust can dramatically change how you interpret your results.

 

[sunshadow]

Page: I would ask the following questions of you.

How do you know these things happen?
What is the intended purpose of your knives?
How do you test your knives?

These are questions I have been asking of myself since I started making knives.

Beyond the obvious (consulting TTT charts ((a quick Google pulled up these ones below)) to answer the question of why my unhardened tangs were squeaking drillbits at the area of transition from spherodized annealed to hardened and tempered on the knives I used to make)

http://www.bondhus.com/metallurgy/body-6.htm

http://www.navaching.com/forge/forge.gifs/heat1.jpg

http://www.navaching.com/forge/cooling.html

http://www.ce.berkeley.edu/~paulmont/CE60New/heat_treatment.pdf

http://pwatlas.mt.umist.ac.uk/internetmicroscope/micrographs/microstructures/more-metals/steel/heat-treated-steel/fe-0.8-isothermal/ttt-fe-0.8-isothermal.html

in my last day job I was a Metallurgical Associate Engineer at an Aerospace Superalloy plant testing everything from the triple-melt 718 that spins at 36,000 RPM at 1800 degrees f inside jet engines to the special alloy ingots that became the main engine nozzles on the Space Shuttle. About a third of my time was spent looking at metal structure under a microscope. I got permission from my supervisors to bring in and analyze the structure of some of my blades and blade steel. One of the areas I looked at was the transition zone between hardened and unhardened steel, and I found lots and lots of pearlite. To confirm my observation I asked the metallurgical engineer I worked with most often who was head of special projects metallurgy to take a look and he confirmed it.

Polish: Down to 3 micron diamond
Etch: 2% Nital
magnification 250-1000x

unfortunately I do not have access to my image files since I no longer work there.

The intended purpose of my knives is to cut agressively anything my customer wants to cut and keep doing that, and testing my knives used to involve looking at sample cross sections under the microscope which I no longer have access to, cutting tests from shaving to carving mild steel and point destruction tests involving things like dropping from a 4 foot height point first onto a concrete floor. I used to do stupid macho demonstrations like cutting my Dodge Diplomat door open (there was a girl involved and the lock was frozen, the knife didn't fail) but I have since grown up.

Oh and by the way I'm currently the president of the local chapter of the ASM International

http://www.asminternational.org/portal/site/www/

Your ball

-Page

 

[Rick Marchand]

Zat all you got, Page?...... meh.....

I am an ABS APPRENTICE SMITH. I endured minutes of keyboard typing and a $60 fee to get where I am today.

 

[Salem Straub]

Rick, if the earth did indeed orbit the sun, we would A: be moving at incredible speed, and fly off the earth, or B: be upside down during the night and fall off of the earth. Any fool could see that. I mean, try a little thought experiment now and then.

Page, what are you trying to say? That you may know something as well about steel microstructures?

Sorry. Enjoyable thread, though. The OP can't help but have learned something!