Bjorn

katana, heat treating and fun stuff

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hello people, I'm working on a katana at the moment, and Its almost ready for heat treating. my question is multi-fold, first of all, I used a bit of jackhammer bit for the blade, and I am wondering if it will take a hamon line, or not. unfortunately I can not be any more specific about the metal, it was what I had lying around. the second part of my question is how much can I expect the blade to curve upon quenching? oh and what is the best way to temper the blade? and a last question is what is the best claying substance to use?

right, thanks.
-Bjorn

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Hello:

Rich you are right on the S-5..it is either that or S-7 Air Hard, hence, no hamon unless you want to cheat and etch one on like all the ones you see for sale cheap on e-bay.

Besides any true sword "nut" will have to admit that it really doesn't matter whether a sword has a hamon or not as long as it cuts like it should.

Alot of the tamashigiri crowd around my area are getting great cuts with 9260 and A-2 blades. I am using my Nagi-Dachi Tachi which is the "monster" of the group but all it really is, well it's styled after the U-no-kubi-zukuri blades, along the lines of a 16th Cent Naginata Naoshi, which really cut well, even though I have been told that I "cut like a peasant" or like I was "swinging a sledge hammer"...

So don't expect much of a hamon on a S series steel unless you etch one on, then again, you really don't need one if you heat treat it right...

JPH (oh Rich,,you doing that show up here in January at the Riviera??)

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Oh oh:
I jumped the gun and re-read the original post///


OK how much is a "bit" of the jack hammer bit that was used?? Do you have a percent of the blade like say 10% of the material??

What you might of done is set yourself up for a catastrophic failure.. Was the blade annealed/normalized in still air (not in any insulating medium like lime) and if so can you cut it with a Nicholson file?? If you can you might be OK in a oil heat treat.

You have any idea at all what else you used for this? I would hate to see something like this let go in HT...what was the original use for the metal you had "laying about"?? This may be a good clue as to what it could be...

Talk to us...the more info you give the better answers we can have..


JPH

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the piece was an extra long jackhammer bit, I used the chisel end for a hardy. no welding involved in this one.

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Bjorn:

Oh ok...when you said a "bit" I thought you used a small amount of the material..oops...lost in translation.. Air harden it and don't worry about getting a hamon cause it's not going to happen...

Rich: The reason why I was asking is the fact that this last week Wally Beinfield talked me into doing that show (we have known each other since he owned "American Blade" magazine before he sold it and it became "Blade" magazine)...and I was hoping I would know someone who was going to be there..

Dunno what I will have to show as yet..probably some of the Japanese stuff I am doing along with some of my more usual offerings...might do a book signing, dunno yet

JPH

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if you want to etch a hamon line you could use a plate steel box filled with salt watr with a comp power generator for your power and cover the blade a protevtive coating the scrap away the coating were you want it to be etched

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That would be if you want to fake a hamon line cause what it produces is not a hamon line but an etched line.

BTW I talked with a smith who's career was resharpening jackhammer bits and out of over a million he had done only a handfull were not simple steels of around 50 points carbon.

Yes those on line lists say they are tool steels but they come from looking at things like Machinerys Handbook where the steel list says that S7 or S5 would make a good jackhammer bit and yes it would. However the cost of stock would be so many times that of a simple steel that the manufacturer tends to go what is cheap and acceptable. Sort of like a Rolls Royce would make a good car but you don't see many smiths driving one!

JPH do you have any *good* documentation to the contrary? A million+ jackhammer bits re-forged and quenched in water is rather persuasive to me.

BTW Test you piece *before* making something from it!

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Thos:

The information I have came diredctly from both Makita and Atlas' tech departments..So at least those two manufacturers use S-7. That's all I can tell you on that.

This is the problem using what I call "mystery metal"...aka "recycled materials" cause you usually cannot be 100% certain what it really is...

JPH

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