Sashimi knife how to

[Sam Salvati]

Finally got off my lazy duff and got around to photoing a how to. This is how I do things, others may have they're own way but this is my way, results may vary . It is a tutorial on how to forge, grind, and mount a sashimi knife, which is a knife made for slicing sushi, but is also VERY handy for slicing anything else also. The chisel type geometry (flat on one side and flat ground on the other makes it possible for VERY thin slices. Enjoy!

PS, I figured it was long overdue I gave back to the community which has given me so much

 

[Sam Salvati]

First off I start with my steel, in this case I will start with Adlo's 1084, a very excellent plain carbon steel sold by a gentleman of gentlemen. It is said to be the best beginner steel, as it requires little to no soak time when heat treating, and can be quenched in oil or better yet automatic transmission fluid either heated to 120F (or for best results a PROPER quench oil like Houghton's Houghto-quench K or Park's #50) I start with a 7 inch piece.

 

[Sam Salvati]

Here is my hot cut, and my anvil. I made this hot cut from a section of leaf spring, it is a double 45 degree hardy , meaning it orients in my hardy hole at 45 degree angles, as well as the edge being ground to give a flat or 45 degree cut depending on how you have it. I use this anvil and my big anvil to work on.

 

[Sam Salvati]

I use my hardy to put a notch at the 7 inch mark, you can just slightly see it in the next couple of photos. I only put a notch FIRST as I want to be able to hang onto the bar of steel instead of using tongs which can be clumsy. I work down the tip first.

INTO THE FORGE!!!!!!

And work down the tip

 

[Sam Salvati]

Next I will work out the profile taper. Make sure to take care and keep the bar the same thickness, we will add the thickness taper later on.

Profile taper

The thickness is a nice and uniform 1/4 inch for now

 

[Sam Salvati]

Now I will hot cut the profile tapered blank from the parent bar. When you do this is your own personal choice, I should have waited until I was ready to forge down the tang but oh well.

Getting ready to hot cut

Cut almost, ALMOST all the way through, then twist off the rest, this way you will not ruin your hardy's edge or mar your hammer face.

The cut off blank

 

[Sam Salvati]

Next you will start and draw out your tang. "Drawing out" simply means stretching and squishing the metal out in length. I take a heat on the end of the bar, then set the amount of material I want to turn into the tang over the face, and leave the rest hanging out over the edge. I will hammer down angling the piece so I get a nice smooth transition, I use the part of my anvil's corner that is rounded so there is not a sharp corner which could be a stress area.

Set it over the edge and face

Then HAMMER! Hit it good, but be careful not to go too far or you will end up with a needle for a tang .

 

[Sam Salvati]

Next draw out the tang. It should be widest at the shoulder, tapering in thickness and width towards the end.

Back into the forge first

The blank so far, profile taper but no thickness taper yet, the tang is drawn out.

So far from the original stock size I started with the blade has grown from it's 7 inches out to 12 inches, mostly from drawing out the tang but from profile tapering as well. I let this growth happen on it's own, though there is ways to calculate how much stock you will need, which you will need to know if working to a specific design or size you want in the end.

 

[Sam Salvati]

Now we will go back into the forge and add some distal taper. Distal taper means thickness taper, the blade will go from thickest at the shoulder area to thinnest at the tip.

Back into the forge

Then forge down on the flats all over to taper the knife. You will start with only a few hits on the base of the blade then move out to the tip where you will hammer more. The more you hammer one area the thinner it will get, so logic says hammer the tip more than the shoulder area. Here is the blank tapered (looks like not much but the shadow didn't help).

 

[Sam Salvati]

Now here we are, we have our blank. Forged to shape, tang drawn out, tapers added, we are ready to forge our bevels.

The blank has grown another 3/4 inches from adding the taper.

 

[Sam Salvati]

Now we begin our bevels. I took two shots to illustrate (as well as finally have a picture on hand of this) the way you would do it if you wanted to form a bevel on both sides of the blade or on one.

Here is how you would hit it if you wanted the bevel on both sides, both the piece and hammer are angled. You will get the feel of this better with practice, but you should and will be able to hold both at the same angle intuitively to attain the same bevel on both sides. But the action itself will also assist in getting both even.

Double bevel

but for a sashimi knife where the geometry will be a chisel grind (flat on one side and beveled on the other) I will hit like this, with the piece flat on the anvil and the hammer angled only.

Here is the bevel beginning to form, I start with a small one on just the very edge then work it back towards the spine angling the hammer less and less.

And here is the blank with the bevels rough formed so far, looks like a sick banana!

 

[Burton Harruff]

Nice work. I like how you have that hot cut at a 45. Keep the pics coming.

 

[Sam Salvati]

We are going to have to straighten before we go any further or will end up with a skinner . My method of straightening is I will form the bevels, then straighten. Some will straighten as they go along, but I find it easier to do it this way. I use a 2x4 to straighten by hammering it onto the edge, it is wood so it does not mar the edge you just worked down. I got this idea from watching an excellent smith by the name of Mace Vitale at Ashokan using an old baseball bat to do this (thanks Mace!).

Here I am banging away

Here is the straightened blank, I then worked the bevels again to refine them further then straightened with the 2x4 again and here we are

Here is the flat side

And and overall shot of the blank so far

The blank has grown now into a blade, and also grown even more in length. What started as a 7 inch bar of steel is now 13 3/8ths long, almost doubled in length.

 

[Sam Salvati]

WHEW what a long day!!!!! Now we have our forged knife, it is forged to shape, tapered, and beveled. Hopefully you kept a careful eye not to work your steel too cold or too hot, but hey **** happens . Right now there are all kinds of stresses built up from the forging process in our steel, and we need to fix that. We fix this by normalizing the blade. Normalization is where you take your blade and heat it up evenly to non magnetic (where a magnet will not stick to the steel anymore), also known as the critical temperature, then go a little hotter then pull the blade from the fire and let it air cool. This brings all the carbon and alloys into solution with the iron, then let's it all relax back into they're separate places. I do 2 normalization cycles, some smith's rule of thumb is 3 but since I will do one more before heat treat and I was careful with my working temperatures I will only do 2 now.

First

then air cool

Second

And let it air cool again

And we are all done for part 1 which included the forging process, part 2 which will include grinding and polishing, heat treating and mounting and final sharpening will continue soon.

 

[Allen Newberry]

Very nice tutorial!

Allen

 

[TekSec]

Very sweet, Sam! I (coincidentally I promise) started a WIP over in the gallery for a Loveless drop point.

 

[Stacy E. Apelt - Bladesmith]

Good job ,Sam.
Stacy

 

[Keith_H]

That is a great straightening trick. That looks like a superb sashimi knife!

 

[69_knives]

Right now there are all kinds of stresses built up from the forging process in our steel, and we need to fix that. We fix this by normalizing the blade. Normalization is where you take your blade and heat it up evenly to non magnetic (where a magnet will not stick to the steel anymore)

Great tutorial, Sam.

I just have one question/concern about the above quoted statement. Just about every text or video I've encountered says that annealing is the step that relieves the stresses from forging, or perhaps I am remembering wrong. Not sure.

Will research this more later. it's late.

 

[Stacy E. Apelt - Bladesmith]

Here is a good link on normalizing:
http://info.lu.farmingdale.edu/depts/met/met205/normalizing.html

here is some annealing info:
http://steel.keytometals.com/articles/art15.htm

Stacy