Do the Kamis temper their blades after hardenning ?

Go to the HI web page and read. The tea pot water poured judicioiusly tempers and hardens at the same time, unless I am mistaken. The blade smiths here can better answer. They know things.




munk
 
Well the tea pot water serves to harden the blade............

but some othee swordsmiths temper the blade in heat of 300 degree Celsius..............which has an effect of making the balde more ductile..........(breaking up much hardenned and brittle steel crystals into more resilient structure...................
 
Someone correct me if I wrong. Water on the edge quenches the steel, hardening it. Residual heat from the spine conducts through the steel to the edge, tempering it. The kamis watch the colors of the steel and can tell if it's sufficiently tempered. Difficult to do properly. Years of experience make the difference.

Steve
 
Whatever they are or aren't doing, brittleness doesn't seem to be a problem for me. I have to beat on metal or concrete to get any chipping and even this sort of damage seems to be more a matter of metal deforming than metal departing.
 
Ferguson, you and munk are correct. It is a "two-fer" deal :D

Japanese swords generally ran their edges "full-hard". They are NOT ductile in the least; if you exam some old swords you will find edge cracks and chips because of this. They relied on the soft spine to hold everything together, unlike most western broad swords that ran a spring temper through-out.

The kami's method of hardening and tempering with residual heat is the same as what was used by most western smiths when making punches and chisels; it is the method that I was taught by my teacher.

stevo
 
So the kamis do not have to temper the blade (reheat).

but I have heard that the blade is sometime softer at outer layer..........which when it is used..............the inner .......harder layer is exposed so that the blade becomes harder when used........

That is why I may think that the Kamis may have tempered the blade !
 
Astrodada said:
That is why I may think that the Kamis may have tempered the blade !
Click to expand...

Think what you like. You have been told the truth. Whether you choose to accept it is up to you.:rolleyes: No one here is going to bullsh*t you except for the part about using the cho for a throwing sight.
And the helluvit is that there are some people in high places that still think that is what the cho is for.
At the J.R.Davis Gun Museum they have a note on a couple of khukuris on dispaly saying that the cho is used for a sight.:rolleyes:
Some people just don't want to listen so it wouldn't do any good for me to take a few khukuris and the HI Website up there to prove it to them that it isn't.:rolleyes: :mad:
 
Yvsa said:
Think what you like. You have been told the truth. Whether you choose to accept it is up to you.:rolleyes: No one here is going to bullsh*t you except for the part about using the cho for a throwing sight.
And the helluvit is that there are some people in high places that still think that is what the cho is for.
At the J.R.Davis Gun Museum they have a note on a couple of khukuris on dispaly saying that the cho is used for a sight.:rolleyes:
Some people just don't want to listen so it wouldn't do any good for me to take a few khukuris and the HI Website up there to prove it to them that it isn't.:rolleyes: :mad:
Click to expand...

Well I have never ever think that the cho is beeing used as a throwing sight.

But I just still wonder that..............a villager is sharper than a normal HI polish blade..........as I have heard........I could be wrong............

That fact....if true..............makes me think that if they are tempered differently..........such that the polished ones are made easier to polish by the Kamis..........but had to be used...........to grind away the outer softer metal to bring out the harder inner edge............
 
Astrodada said:
But I just still wonder that..............a villager is sharper than a normal HI polish blade..........as I have heard........I could be wrong............

That fact....if true..............makes me think that if they are tempered differently..........such that the polished ones are made easier to polish by the Kamis..........but had to be used...........to grind away the outer softer metal to bring out the harder inner edge............
Click to expand...

Just because the village khuks are sharper doesn't mean they are any harder, just that the edge hasn't been polished over. Some of the villagers also have to have the softer material sharpened off before they get down to the hard stuff.
The only way that buffing, polishing, the blade could make it softer is if the kami "burned" the blade taking the hardness out of it.
In that case the khuk would be ruined at that particular spot and no amount of grinding would bring it back to hard material.
 
The opening paragraph here:
"Steel industry / Users use same technique as kamis! "
http://www.bladeforums.com/forums/showthread.php?t=287094
is something that comes to mind fairly often.

A temp/color chart is included in that article---

Table 1.
Temper Colour
. . . . . . . . . .Temperature
Pale straw ..........230 °C ......Planing and slotting tools
Dark straw ..........240 ..........Milling cutters, drills
Brown ................250 ..........Taps, shear blades for metals
Brownish-purple ...260 ..........Punches, cups, snaps, twist drills, reamers
Purple ................270 ..........Press tools, axes
Dark purple .........280 ..........Cold chisels, setts for steel
Blue ..................300 ..........Saws for wood, springs
Blue ..................450-650 ....Toughening for constructional steels


Lots more heat treat info too.



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Astrodada said:
So the kamis do not have to temper the blade (reheat).

but I have heard that the blade is sometime softer at outer layer..........which when it is used..............the inner .......harder layer is exposed so that the blade becomes harder when used........

That is why I may think that the Kamis may have tempered the blade !
Click to expand...

You have a hardened "sweet spot" that is tempered by the residual heat of the portion of the blade not hit by the water.

The balance of the blade is not hardened and doesn't need to be tempered (because it was never hardened in the first place).

That means the rest of the blade is rather soft to absorb impact.
 
Had the opportunity to Rockwell test a khukuri the other day (not an easy task!)

The edge was around 58 and the spine area was around 25.


Just thought I'd throw that out there....:D

(I have nothing to add regarding the question...sorry! :( )
 
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