Knifemaking - Forging and
Tempering a Blade with Chainsaw, 5160 and Brass
Adding brass to a san mai blade for decorative purposes and then
heat treating it properly using a really low tech solution.
Folder blade in san mai damascus with a 5160 core, chainsaw laterals
and brass applications.
Knife making process
Chainsaw and a SAE 5160 8" x 1 1/2" x 5/32" flatstock.
(Pictures 1 and 2)
Electric welded the chain to one side. (Picture 3)
Then the other. (Pictures 4, 5 and 6)
I wrap that in two 0,5mm thick sheets of stainless 304 to prevent
welding agains the cannister. (Picture 7)
Then I place it inside the cannister. (Pictures 8 and 9)
And close it. (Picture 10)
Then I place it on the oven at 1300 C (Picture 11)
And press it with my hydraulic press using 30 tons. (Picture 12)
As it comes from the press, now the chain is welded to the sheet of
5160. (Pictures 13 and 14)
I start cutting the cannister to remove the inner piece. You can see
how the stainless sheet works perfectly. (Pictures 15, 16 and
Once I remove the chain/5160 combo, I cut a 11/8"
x 5 1/2" piece. (Picture 18)
With two 2mm thick brass sheets. (Picture 19)
I repeat the previous process adding the brass sheets between the
chain/5160 combo and the stainless 304 sheets. (Picture 20)
Smaller cannister. (Picture 21)
And in they go! (Picture 22)
Closed cannister. (Picture 23)
Into the oven at 830 C (Pictures 24 and 25)
Pressing it again. (Picture 26)
After pressing and cooling. (Picture 27)
Grinding the borders to get the inner content. (Pictures 28 and
Final piece. (Picture 30)
After I cut and grind some, the rough folder blade shape is there.
The damascus is not etched yet, but you can see the patterns underlined.
(Pictures 31 and 32)
What's important when you're adding other melted metals
to the blade is that you make the desired final thickness from the
get go. The piece I've posted in the first posts was the second one
I had to make for this project. You'll see why in the next pictures.
This is a chainsaw welded to a SAE 5160 flatstock, made exactly like
I've showed before. (Pictures 33 and 34)
I don't press it to flatten everything as I need the empty spaces
from the links to receive the melted brass later, right? (Pictures
35 and 36)
But then you get to realize that this is still too thick for a folder
blade... (Picture 37)
And when you press it more to flatten it to the proper thickness,
you lose the interstitial spaces to accomodate the brass, and you
end up with an ingot like this, with not enough brass on it, that
once the blade get ground, it's gonna lose even more. (Pictures
38 and 39)
And this is why you have to consider all of these (thickness, blade
shape, and type of grinding to be done) before start making the piece!
Blade Tempering Process
This is not the same blade as shown before, but the process is exactly
the same, as it's the same composition.
I picked up the use of potatoes for this type of projects when I was
working on the Argentina train company many years ago. Sometimes flat
screwdriver's tips get broken, and since we couldn't just order more,
we forged the tip to proper shape again. And in order for the handle
not to get burned or melted, we stucked a potato or two in there.
They dissipate the heat very well and it's a really low tech and cost
solution that just works.
I would estimate that the non exposed blade part get to aprox 200C,
not more. Since I'm using 5160 for the blade and I've been working
with it for a long time, I already know the exact color the steel
gets (light red) to the needed temperature (840C) Preparing the potato
of the right size to receive the blade. (Picture 40)
Presenting the blade in place. (Picture 41)
Securing the blade in place with some wire. (Picture 42)
Getting the torch ready. (Pictures 43 and 44)
Starting to heat the blade. (Pictures 45 and 46)
Exposed part of the blade gets red hot and ready to go. (Picture
Just don't take the exact color of this picture as there are lots
of variables involved.
Quenching it in 60-80C degrees oil. (Picture 48)
Resulting piece. (Picture 49)
Cleaned up blade. (Picture 50)
Second HT session (C degrees) I place the entire blade here, as at
that temperature, there's no problem with the brass. (Picture