Japanese Leather Knives

[zuludog]

I've been Surfing on YouTube over the past couple of weeks as I'm thinking of making a kiridashi (a small Japanese knife), and I'm always interested in seeing any methods of sharpening

I came across this video, using home made knives from old hacksaw blades, and they certainly look pretty good

'The Best Leather Cutting Knife' by Leathertoolz

The guy obviously knows his stuff, and he's done lots of other videos, on Japanese leather knives, awls, sharpening, and various reviews of other leather tools

[Art]

That type of knife has been used in the shoe trade for hundreds of years. If you use them heavily (like a cobbler or shoemaker would) you have to sharpen them often, but that goes for most knives. I have no idea what they make saw blades of today. Back in my day, usually O-6 or L-6, both good oil hardening steels. Less than a flat 10° bevel, one side only makes a great skiving knife, wrap the handle with split, some folks just use duct tape, and you are good to go.

One thing to be careful about. In the past, you pretty much knew what metal was used in common tools, saws, files, drills, etc. This is not necessarily the case today. Materials science has come a long way since my dad and I worked in the shop, and I could pretty much count on a file to be O-1 or W-1 or 2. Now they use sophisticated metals that have complicated heat treats, and are oftimes just a cheaper means to profit. Files are not "superior" anymore, they are good enough. I can imagine that saw blades (bandsaw - hacksaw) are not the same either. You don't want to know what has happened with "drill rod".

Art

[leathertoolz]

Hello.

This is leathertoolz from youtube channel leathertoolz

the steel used with my hacksaw knife is high speed steel.

it is mordern steel with good wear resistance than plain carbon steel.

I agree with Art on low quality materials used on tools nowadays.

but process and producing steels have advanced too. so if you pay good money on worthy steel, you will have better result.

Edited February 17, 2016 by leathertoolz

[Art]

Leathertoolz,

Saying high speed steel is like saying car. Car is different from truck or boat, but there are a whole lot of different cars. High speed steel means generally that it can cut metal and be somewhat impervious to friction in addition to providing a decent finish. The high speed part generally translates into more feet per minute of tool speed, nothing really necessary in a leather knife. These steels range from M2 which has been around since I can remember, to M42 which I also remember quite fondly. These high speed steels don't like to be bendy, which might preclude them from duty in the thin knife department, like I said, the tool manufacturers endeavour to be nebulous concerning their metal compositions, probably because if you knew what they were using, you might buy something else.

Art

[leathertoolz]

Leathertoolz,

Saying high speed steel is like saying car. Car is different from truck or boat, but there are a whole lot of different cars. High speed steel means generally that it can cut metal and be somewhat impervious to friction in addition to providing a decent finish. The high speed part generally translates into more feet per minute of tool speed, nothing really necessary in a leather knife. These steels range from M2 which has been around since I can remember, to M42 which I also remember quite fondly. These high speed steels don't like to be bendy, which might preclude them from duty in the thin knife department, like I said, the tool manufacturers endeavour to be nebulous concerning their metal compositions, probably because if you knew what they were using, you might buy something else.

Art

Yes, saying high speed steel is like saying a car. I know what you meant by that. My hacksaw knives are made of M2.

High speed steel intended to stand a heat. and also it became harder because of tungsten or molybdenum.

and that makes the edge crazy sharp and stay longer because micro burrs don't bent easily.

being hacksaw, it has good flexes on the body too : )

[Oldtoolsniper]

Here is the one I just made. The blade is from a simonds hacksaw blade that is many years old. They came from an estate sale from a farrier. Red tang or some such name.

Art,

I was wondering about the new stuff. By the way I got the idea from the video. It was fun to do. And cuts really good.

[Joachim]

I have made quite a few knives. I also have a couple prototypes for the style kiridashi. I also made a skiving knife. For almost all of them I used old lawnmower blades. Super strong steel and If I mess up the heat treat I can redo it. It requires a little more grinding but in my opinion it's worth it because you have basically any kind of knife you want while spending little to nothing on steel.

[mike02130]

Just a bit of info.  Japanese knives are labeled blue paper steel (Aogami) and white paper steel (Shirogami).  In the west it is just commonly referred to as blue and white steel.  The colors are from the color of paper or wrapping that designates the grade of steel from Hitachi steel company.  The blue is harder than the white, yet the white will take a sharper edge.  The hollow on the back of the Japanese knives, chisels and the like is called an Ura.  It helps with sharpening (like a Scandinavian grind) and needs to be flattened at the edge.