5160

[Cobalt]

And yet another pilfering job by Cobalt:

Can you guys tell that I had a lot of time on my hands.

Somewhere in this mountain of info there's something about this. I tested early on and found edges to be generally 56 to 58 Rc, sometimes a little harder. Will Kwan recently got an HI khukuri that was more than 60 Rc and had to work it down to the desired 58 or 59 Rc to sharpen it right. The back is soft, sometimes Rc 35 or so. Tang is dead soft, and tip is softer than 56.

And the steel is ususally 5160 unless the kamis happen to run across a spring made of something else which I am not sure is a possiblility or not.

Anyway, hope this helps. Floyd who posts as FO did a couple of tests I think. Maybe he'll add his two bits.

Bill

 

[Cobalt]

Some more 5160 specs:

0.60% C
1% Mn
0.9% Cr
0.3% Si

Balance is Fe of course.

These values are approximate and can vary slightly of course.

 

[Will Kwan]

The kami's work the knives in a charcoal fire (carbon rich). While this is not as good as packing the blade in carbon, I wonder if the knife is case hardened to a degree.

Will

 

[Bill Martino]

Will, this could well be but I think (could be wrong here) case hardened blades are subject to chipping and flaking when bent and Hi blades don't chip or flake when bent.

Uncle Bill

 

[Cobalt]

Will, you are right that there could be a bit of case hardenning effect on the steel. Probably not more than enough to make it behave like a steel closer to .9-1% carbon or so. This also retains the ductility throughout the rest of the blade. But this is only a guess since it is not intended as part of the forging process.

Since this steel is such a good steel to use for large heavy blades, I don't see that it makes to much of a difference, but it is nice to know.