# Communities > Bladesmiths, Blacksmiths, Artisans and Professionals > Japanese-Style Sword Makers Cafe >  New Tanto pics

## Gary B

There hasn't been much action around here lately, so I thought it might be OK to post a couple pics and vent a bit.

It has been quite awhile since I last broke a blade like this so I guess I was due.  Even so it still really ticks me off to crack a blade in the quench.  Even on a small blade there is quite a bit of work involved to this point.

The first one shows how I had it clayed up . It is 1/4" thick 1070 steel. It _would have had_ a prettu wild hamon if it had survived.

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## Jesse Pelayo

I'm curious...where did it crack?

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## Gary B

really hate AOL!!? Anyway it loaded half the pic. This next one is shot of whole blade after quench and clay scraped off.

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## Gary B

This one is a closeup of the major crack. It is about 1/3 of the way back from the tip. There are two other smaller ones nearby.

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## Dan Pfanenstiel

Hey! I recognize that crack! Hate it when that happens.

Forged my first katana last weekend and it was going great until the quenching. Somehow I didn't realize that some of the clay had fallen off during the first 3 seconds as I pulled it out of the water for an interupted quench. It went back in the water and finished the quench and all the clay fell off. Warped like sunofagun which threw me a little since it happens less and less these days. while it was still warm, I tried to do a little straightening and snap! off came 4 inches of the tip. Blade had hardened up to the spine in a couple of places where the clay had fallen off. It's a nifty wak now with a crazy hamon.

Dan

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## Joseph Renner

Sorry guys.
Those things just seem to happen when you want it the least.

But then the ones that make it are all 'round better due to it. 
keep bangin' and abradin'  :Big Grin: 

Joe

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## Daniel Gentile

Gary,

Well as much as I can tell from looking at the pictures it looks like it was overheated... cracks from overheating happen a lot.
Why I guess this? -> it has this "spot-marks" (little dots) on the surface... Specially in the Hamon-area... as well the hamon looks a bit grainy...

This normally happens with overheated blades.

It does not absolutly mean that the overheating took place during your Heat Treatment... It could come from froging.
And then either not good annealed/normalized or really heavy overheated.

I don't know. 

One trick for Heat treating temperatures which works well with plain carbon steels like the 1070:
Check the temperature with a magnet... the steel looses it's magnetic-properities as soon as it reaches the critical temp.

Don't know maybe I'm wrong...


Daniel

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## Joseph Renner

Im pretty sure the dots are from the quick acid etch, not nie. Over heating doesnt cause cracks as easily as one might think. Overheating is as likely to cause it not to harden properly, ex: the hotter, the longer to drop below 900, so temp(as well as soak) plays a good role in the hardenabilty or hardening depth.

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## Gary B

In a way you are both right. I think it was overheated a bit, but the soak time was a little long also. One of those deals where, when judging temp. by eye, I pulled the blade out of the fire and thought,.."maybe  just a little bit more. I thought I saw a sort of dark spot there"...and went back in the fire for a bit.

It has been my experience that so many factors have to work together that several can be just a tiny bit off and in aggregate cause a disaster. Also it seems every time I am in doubt for a second and hesitate instead of just going for it that is when I blow it.  It happens now and then to everyone I imagine.

Like Joseph said, It is the failures like this that make the successes even sweeter.  This thing sort of ruined my day yesterday, but the next one will work great and I'll have a really great day. :Big Grin:

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## Daniel Gentile

To Joseph,

as far as my understanding goes, NIE has nothing with overheating spots in common.... Overheating spots are seen on the whole surface, but surely can be more visible in the areas of a hamon...

Nie, Nioi, konie are desirable "effects" visible in the habuchi area.
 a result of "perfect" heat treatment... which clearly would not include a broken/cracked blade..

habuchi is the area which forms the transition zone between the soft part of the blade and the martensit-part (the yakiba, hardened edge).
The Habuchi area can include visible (after polish) martensit-particles which either are refferd to as Nioi (diffuse visible) or Nie (only slightly visible). There are different grades of both possible, then reffered to as Konie.
All of this forms what is called "hamon".

Nie is generally more visible as "dot-shaped marks"... so I guess that's why you thought of nie when reading my post.


If you've any questions, feel free to ask...

Again, my understanding of all this is limited, I guess here on the board are many who could clarify this better than I could do.


Daniel

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## Joseph Renner

No-no-no
Nie can occur anywhere(sub names will then apply BTW), its generally in the habuchi due to an insulating effect from the lip of the clay. Ihave made a nie deki peice(and destroyed it) and have come to understand it. Nie is large visible grain, not only from overheat but held overheat.
Calling them desirable effects is very presumptious. If you(the smith) desire it, its desirable, if not its not so great. Its a control thing, you can skillfully control these things. Traditionally there were reasons for it. A matter of manipulating the material the best way. 
For most of our modern materials its not a great thing, this is quite a generalization though.

You have to really think about it and aproach from all angles to understand it even a bit.

Joe

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## Daniel Gentile

Joe,

Thanks for your reply...
Interesting though...

But I thought that the term nie/nioi... is exclusivly used for the martensitic-particles in the habuchi area and no outside of it...
At least all my books reffer it as such.
But I'm sure the japanese have names for "nie-like" "effects" outside the habuchi as well. (they have names for anything  :Smilie:  )

And I would not speak of nie as an effect reached by OVERHEATING... because overheating is OVER heated.
it's more a result of heat control within it's limits.
Overheating (heating the steel above it's upper limit of the temperature range for the hardening process) is never wanted, nor does it do anything positive to the quality of a blade.

I had effects of nie and nioi only when I was haveing the verry exact temperature and a perfect claycoat with nice ashi lines.

Techincally speaking, I guess you have to have exact AC1 temp. for the whole yakiba and a a little bit above, and then the clay will do it's job.


Please let me know what you and maybe others think/know as I'm looking always forward to learn more about yaki-ire.



Daniel

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## Joseph Renner

Here was a nice thread on another board.
http://www.swordforumbugei.com/ubb/F...ML/000231.html 
Lots of thngs were discussed here.

The term overheat has some merit, heated over AC1. A better way would just be to say higher temp, yea.

You have nie, ji-nie and chi-kei.

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## Daniel Gentile

Joe,

many thanks for the link you've proveided above... specially the posts of keith made on the bugei forum have been helpful, to extend my knowledge of this...


But back to gary's tanto:
A  few years ago I had a rate of broken/cracked blades and surviving blades of about 50%... the reason:
my forge was located outside at this time, so I had only daylight available or sometimes worked at night... Judging temps was not really accurate... but my loss-rate-factor drastically improved (lowered) when I started to use the simple magnet-check. it works wonders.
Well later I got a digital temperatur controller and some other toys... which, as long as you know what you're working with (steel alloy) saves a lot of time and makes results much more reproducable.
But still the magnet method find's it's use in my shop when working with "new" damascus compositions  or unkown steel (which I only rather seldom use, as I like constant quality) I don't use that "junkyard steel" anylonger (only for fun once in a while), I have me few steels, which I've come to know and know what they will produce and can be used for:
For Japanese Carbonsteelblades (non laminated): W2, 1075 and Railroadtrack of which I've got a lot, analyzed and at constant quality and almost for nothing.
For normal working knives: 01, W2, L6
Damascus: 01+L6 is my absolut favorite... it welds nice, is completly hardenable and 'cause of L6's nickle content gives good contrast.


Daniel

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