New knife build - seeking feedback

[Shawn Pixley]

So the kitchen knife thread got me thinking, "hey, I have some Damascene steel I made a while back. Why don't I make a sushi knife out of it?" Yanagiba are long, slender knives that cut fish on one smooth pull stroke. I was impressed by the commentary from David, George, Stanley, Derek and others around the qualities of various steels and their utility as knife or edge material in various threads and in particular the kitchen knife posts.

image.jpgimage.jpg

This billet is made 5160 spring steel and 203 low carbon steel. It is roughly the size needed for a long bladed Yanagiba.

image.jpg

Typically the yanagiba or yanagi ba has a blade length of between 10 and 12 inches. It can be either partial or full tanged. I'm thinking of a full tanged version. The handle would be between 5 and 6 inches in length. It would be a single bevel (right side as I am right handed). So my process (questions) are as follows:

I plan to cut the shape using a angle grinder with a cutting blade as I don't have a metal cutting band saw.
I was going to create the bevel with a belt sander and a jig at the appropriate angle.
I will hollow the left, non-bevel side with files and coarse stone.
I was planning to harden using a peanut oil quench (that's typically what my wife and I use). I wasn't planning to clay the back.
I'll temper in the oven (did I mention my wife is very tolerant)
I would etch with muriatic acid.
I plan to pin the tang to the handle (I know this is not traditional). The handle would be some curly maple I have. It would get a silver trim and horn front if I can find some.

So my questions to the experts:

Am I missing anything? I'm mostly worried about cutting out the shape.
Is there a better way of hollowing the back?
Are there things I should do differently?
Any advice?

[David Weaver]

I'm clearly not the expert here about knife making because I've never made anything but marking knives. But I can relay what i've seen. Traditional japanese knives were scraped on the back. A few makers still make them that way, but very expensive makers (monzaburo or shigefusa? Can't remember which one I saw). Other than that, i can't comment much on the making process. I wish I could find a video of one of the makers scraping, because while it's not machine fast, they are scraping metal out of the back of a knife blank surprisingly fast.

I think the 5160/low carbon combination might come up short in carbon/hardness. Typical combinations for razors end up around 0.8 or 0.9 carbon, and both steels used are in the 0.75 to 1% carbon range (1095/15n20 is one I've seen).

I think 5160 might be more of a machete type steel IIRC where it's used.

I have only seen one person dipping a razor and that is mastro livi. He used ferric chloride mixed in water.

https://www.youtube.com/watch?v=VJENBAB85EE

(at 40 minutes for the ferric chloride - not that there's much to see)

Anyway, even in the 1095/15n20 combinations where the two steels aren't that far apart, the razors have a reputation for having one part of the mix not sharpening as well as the other - leaving tiny chipping in one part of the folded steel and a good edge elsewhere. I think you might get soft edges where the low carbon steel is - do you have any thoughts about how much of each was used, like was it a 1 to 1 mix?

[george wilson]

5160 has .60 carbon,which is very low. I would at least quench it in water. It probably will not reach full hardness in peanut oil.

No doubt it will warp being beveled on only 1 side,but you can heat it up to 300º and twist the blade straight while it is still hot. When cool,it would snap off,so work fast and bend it like a noodle while hot. Reheat if necessary.

I don't think this will make a decent knife,though. It may get sharp,but will not have a durable edge.

You don't need anything fancy to bring out the pattern. Lemon juice will do. I've even used clorox,but don't let the clorox etch the steel too deeply.

[Shawn Pixley]

Thanks David and George

I agree the steel is not ideal for a durable edge. When I was making this particular billet, I was working on my forge welding technique and I used a formula from the web. I believe there were 5 layers of 5160 and 4 of the other. It probably won't be the most durable edge but cutting filleted fish doesn't dull things too quickly.

David, I'll look up the scraping technique. That sounds interesting.

[David Weaver]

Just a side comment, because I neglected to say it earlier, regardless of the alloy, it's a really pretty piece of patterned steel.

[Shawn Pixley]

Thanks, I thought so too. Sometimes, even the blind squirrel finds the acorn...

[David Weaver]

Shigefusa, using a sen (at about 4:00). All it takes to make a sen is to have some good quality high carbon steel and temper it very little and profile a 90 degree edge or thereabouts. It doesn't have to be super sharpened (something like 400 grit is fine) as long a the edge is crisp.

https://www.youtube.com/watch?v=zNPc6xBBiLk

I think you could make one for one time or a few time's use by making a wooden handle and mounting a small piece of hardened carbon steel (you harden it, of course) that you drill, obviously before hardening. The huge sen the guy is using looks nice, but that'd be a lot of work to make and harden something that large.

[David Weaver]

Actually, watching the guy sharpen the sen, it looks like he's sharpening closer to 70 degrees. I'd do what he does.

[george wilson]

If you want a "square" or rectangular bar of steel type scraper,I have found it necessary to hollow grind the bottom of the scraper to make it cut AT ALL. The gunsmiths made a scraper of 18th. C. style like that for scraping sword blades. It would not cut,so they brought it to me to figure out(like everyone else did!) I ground a shallow hollow in the bottom,and it then had relief so it then cut quite well.

They also made a thread tap that would not cut. Once again,they had not ground relief into it.

[Bruce Haugen]

How much relief do you recommend for a scraper like that, George? I've made scrapers out of used up files. Some worked, some didn't and I never knew why. Maybe this is the answer?

[george wilson]

I used the 8" dia. contact wheel on the Wilton Square Wheel Grinder to get the concavity. Now,it is possible that an experienced Japanese scraper could just cock the rear end of the scraper up a bit to make the leading edge bite. But,that would take a lot of expertise to keep the scraper from just digging in and chattering. This could be counter acted by changing the angle of the scraper with each stroke.

sorry, I have had to be nursing my wife constantly these past few days since her surgery,and haven't had time to view the video.

[Ryan Mooney]

Don't grind the edge to fine prior to hardening or you'll a) risk burning it and b) possibly loose to much carbon unless you're firing it in charcoal or something similar to re-add carbon.

It is a pretty piece of steel, looking forward to seeing it in a knife!

[Fitzhugh Freeman]

Just a quick thought: When I made a few blades (cabinetry float, plane blades, small knives) I had trouble finding answers to a range of specific questions. In the end someone suggested I check out the various knife makers' forums (usually within a general knife oriented forum). It ended up being a great help since so many members make their livings making knives.

To be clear, I'm not in any way suggesting George, Ryan, David etc. are wrong! Just that you may find it useful since there is such a concentration of experience there.

Of course you have to be a lot more careful to ignore the would-be ninja types there than here. It's too bad most 13 year old boys don't find a chisel or hand saw as intrigueing as a huge knife with a spiky hand guard and a name like "THE ZOMBIE ABLITORATOOOOR!" And what is it with slicing up hanging dead pigs? ack. Ok, I've gone way way off topic, but truly, if you can put up with the vocal minority of odd types you'll find a much greater number of really helpful true artists who are as willing to share their knowledge as the greats here are. People who live and breath their art and are happy to share it with others, as we have here.

[Shawn Pixley]

So, I've made some progress on the yanagiba. I have the rough shape. I need to reflatten it and drill the tang holes. After that I'll rough cut the bevel and inlay the back. Then I'll hollow the back (left side). Then on to heat treating.

image.jpg

My shoulder is tired from filing. It didn't help that it was hot here without any wind.

[Jim Matthews]

Wow.

How's your neck, after all that?
Will a wooden handle be fitted?

Will you give your knife an auspicious name?