Category Archives: Blacksmithing

Videos of Japanese Blacksmith Forging Kanna

This is a follow up to my previous post on ura. I’ve had these videos for a while, every time I watch them I spot something new, great stuff! I’ll keep the comments brief and let the videos speak for themselves. If the footage seems strange its because it was shot with a cell phone inside the Takanaka carpentry museum.

The tool steel for the lamination has to be tapered on the back end so that the forge weld line is neat.

The forge weld.

Here is using sen to carve the ura, among other amazing things. It looks like the ura shape is pre-forged.

This video has an interesting shot of honing the ura on the edge of a stone, as well as coating the blade pre-quench with clay slip.

To finishing things off today, more final shaping and straightening.

If you liked this stuff I made all the various videos I have from Takanaka CM public, enjoy!

 

Grinding the Ura and Why

So you want to make some Japanese cutting tools, kanna, whatever, and you get past the hurdle of forge laminating tool steel to something softer. Then comes flattening the back and there is a wide ocean of very hard steel to waste away your expensive sharpening stones. How about hollowing out the back (Ura) and greatly easing all of the subsequent work?

The old school approach would be using sen on the annealed blade prior to hardening, but a quick look at most of my own tools from japan show a ground finish. Sen, well, are nice, but it takes the time and charcoal to make them and even full process annealed tool steel is hard stuff compared to the buttery/gummy consistency of lower carbon steel. Sen are also near impossible to use without a rock solid sen-dai.

Apparently I’m writing a blog post about something almost no one on the internet cares about. If I was writing about katana it would be a different story, plenty of interest there. Certainly there are many talented modern swordsmiths outside of Japan who could do a good job making tools, you know, stuff not made for killing people. Why don’t they give it a try (nudge, nudge). If you care to search for methods of hollowing ura dear Jason Thomas pops up, but he’s to busy swinging in his hammock daydreaming in Hawaii to help us poor uneducated blokes out. Just kidding, I’m sure he’s hard to work at something, which we all would like to know!

Back more to the point, how does one hollow the ura without a lot of fuss? I use the edge of my 8″ grinding wheel, which is just about perfect for backs 1/2″-1″. You can even make a little jig consisting of a board with a fence hinged at one end to keep the grind radius centered on the tool.

Take as an example this little kanna blade for a dovetail plane I made from some 0-1 steel forge laminated to mild steel. You get it all dimensioned and pretty in the annealed state and then quench it and it warps. So you temper and some of the warp comes out, then you can hammer straighten it at the anvil to the best of your ability, hopefully without cracking the tool steel. If you already had the ura shaped it wouldn’t be even by the time the back was flattened on a bench stone. And everyone wants that nice aesthetically pleasing ura.

Grinding the ura after tempering saves a ton of work. If you’re making narrow tools you’ll want a stone smaller in radius than 8″, if you’re forging kanna you’ll find yourself lusting after the really large Japanese water cooled grinding stones.  Some ura are elliptical, some a more true radius, let your eye be the judge of the progress.

I’m trying to save wear on my sharpening stones, they wear down fast with work like this. In the above photo the back was still low at the cutting edge, so I took the blade back to the grinding wheel several times and ground the ura back completely to the outside edges of the blade.

Here’s the finished ura, done freehand. Its not perfect, but you wont hear me complain.  The grinding gets shallower towards the cutting edge, the shape produced naturally by the radius of the grinding wheel, easy right?

Two blades, my best forging work by far, ready for a dovetail kanna dai to be made.

The bevel on the kanna looks weird because it tapers across its width. A dovetail kanna is a side escapement plane, there being no wedge, it is held into the body by said wedging shape. The knicker iron is also a tapered sliding dovetail. I quenched the knicker iron a bit too hot and its coarse grained, you can feel it when sharpening. The blade though, maybe good enough for me to sign.

I need to get my hands on some wrought iron.