In this video, I show how to make a knife
for Kabab Barg which is a Persian style barbecued
lamb.
The blade is going to be about 12in long and
2in wide.
The knife needs to be very sharp for cutting
fine slices of meat.
I will forge the blade from antique wrought
iron for the back and a high carbon steel
for the cutting edge.
In the first step, both the wrought iron and
the high carbon steel are prepared so that
they can be forge welded together.
I am aiming for bars that are about 3/8in
thick and a little bit less than an inch wide.
Once the bars have the right dimensions, they
need to be cleaned up and fitted so that that
they can be successfully forge welded.
While it clearlier would have been much simpler
to start out with stock that was already the
right size, I only had big bars of wrought
iron and W1 lying around.
During forge welding, the two bars are joined
together in the forge fire until they behave
like a single piece 
of metal.
After the pieces have been forge welded together,
the tip of the knife is created by reverse
cut that will be forged over.
This creates an aesthetically pleasing flow
of the W1.
After the knife tip has thus been created,
I establish a distal taper that reduces the
width of the blade as it gets closer to the
tip.
One of the tricky parts in creating this knife
is forging in the shoulder that clearly separates
the blade from the tang.
To do this I drive a wedge into the steel
with the power hammer.
It is important to support the blade evenly
on the bottom die so that the back of the
blade is not being distorted.
Afterwards, I draw out the bevels using a
helper on the power hammer and also by hand.
As the forging in the bevels causes the knife
to bent, it needs to be straightened out occasionally.
Another shoulder needs to be forged in to
create the tang.
The power hammer makes this quite simple.
At this point the knife has been completely
forged.
I heat it up to critical and let it cool in
the air to normalize the metal.
The remaining steps are quite time consuming.
The scale needs to be cleaned off the blade
and then the final geometry is established
by spending many hours with the belt grinder
as well as by draw filing.
Once the edge has been thinned, the knife
is ready for heat treating.
The first step is to normalize the knife again.
Once it has reached its critical temperature,
it is slowly cooled down in the air.
By criticial temperature I mean the temperature
at which the blade is non-magnetic and all
carbon has been disolved into the iron.
The next step in the heat treating regime
is to quench the blade when it is at critical
temperature to rapidly cool it down.
This causes maretensite to form which creates
the hard cutting edge.
Using a file to test the edge result in it
skidding over the surface rather than biting
into it.
The last step in heat treating is to temper
the knife.
This reduces the hardness but makes the steel
tougher.
For this knife I temper at 400 Fahrenheit
for an hour.
To fit the bolster I use a file guide to create
a small transition which helps with achieving
a tight fit.
At the back of the knife is wrought iron,
a file cuts it without much trouble.
However, to file the W1, I need to more aggressively
temper the steel.
Rather than drilling and filing the slot in
the bolster, we use the blacksmithing approach
in which a slot is punched and then opened
up to the right dimension with a drift.
This is much easier as a two person operation.
The final fitting is done using the tang of
the knife.
I use a stencil to scribe an oval shape onto
the bolster which I then use as a guide when
grinding.
For the handle, I use a piece of African walnut
on which I trace the outline of the tang using
a pencil.
Holes are drilled using a drill press and
a long drill bit in a hand held drill.
These holes guide the tang as it is being
burned into the wood.
Burning the tang into the wood requires many
repeated cycles of heating up and burning
it in.
It's not quite as simple as it appears on
the video here.
At this point all the pieces fit together
and the handle needs to be slowly shaped.
Now is also a good time to start making the
knife sharp by thinning out the edge.
All vertical grinder marks are removed by
sanding the opposite direction by hand.
To bring out the structure of the wrought
iron, I place the blade for ten minutes into
ferric chloride.
The final step in assembling the knife is
to glue everyting together using a fast setting
epoxy.
Once the epoxy has fully cured, the transition
between the bolster and the handle is cleaned
up on the belt sander.
Great care needs to be taken not to cut with
the belts into the blade.
Afterwards, the wood is sanded down by hand
to 220 grit in order to remove all marks left
by the belt sander.
To seal the wood, I use True oil which is
a mixture of linseed and tung oil.
For this knife, I applied 5 coats which are
cleaned up with fine steel wool once the oil
has dried.
Before the knife is completely finished, it
needs to be sharpened.
I used oil stones for this which progress
from coarse, to medium, to fine.
And here is the finished product.
A big knife for cutting thin slices of meat.
