A Japanese Saw Sharpening Vise

Its long overdue that I make a better saw sharpening vise. Jason posted this great diagram of ChoMasaru’s vise quite a while ago when he put one together:


The image quality is not so good, but it looks to be in shaku scale.

Odate has a small diagram of a saw vise in his woodworking tools book, which I had used as the basis for the last one I made, but I was never happy with it.

I started by making a rule with sun (寸) increments (30.3mm) using a piece of kumiko I had laying around.

And then joined up some white oak, wide enough to fit the full length of my 350mm rip saw which tends to see the most sharpening of all my saws.

From the diagram a wooden pattern was made to trace the shape on the edges of the joined white oak.

I started on the inside of the pattern, slaying the waste with a router.

The rest of the inside shaping was with hand planes.

Before starting the shaping on the outside I clamped both pieces together to match drill for the small bolts I used to hold the two pieces together.

I had a newcomer to the shop as well, making a fidget spinner out of wood. The irony of someone getting completely absorbed and spending hours and hours making a small toy meant for people with attention problems was not lost on me. Young people need tools in their hands, not fidget toys. I could do without my tools being dropped on the concrete floor though, best to have a student set of stuff on hand for such occasions . Oh, and a first aid kit for when they cut themselves, which they always do, no matter how carefully you explain the whole “don’t cut into your hand with the chisel” thing.

After drilling for the bolts the rest of the outside profile was cut. I sped things up a bit with a power planer before refining with a low angle block plane.  Too much time lost to repairing a chipped plane blade dropped on the ground, haha.

Fitting the wedge took a while, I started off with an angle too obtuse to stick in there.  Now I just need the little box to lay it up against and collect the filings. Having a good vise for filing makes all the difference in getting nice teeth geometry, and the ChoMasaru pattern is beautiful!

My shop is located at the other end of this rainbow if you want to visit.


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!


Making a Dovetail Kanna

Here is a Japanese dovetail plane, a simple style for cutting the male part of a sliding dovetail joint. Its a nice little plane, about eight inches long, great for one handed use cross grain or long grain. I had the chance to fall for this little guy up in Vermont and have wanted one ever since. With that in mind I took the time to make tracings of all the parts in my design notebook. Well worth the effort!

I’m short on good dai wood, quartersawn white oak is the best I have and it works okay for planes, not the best but ok.

All the various lines were marked out. If you’ve never cut a dai before this is not the first one that you want to start with. Having learned about western style side escapement planes helped me a good deal. You don’t need plane makers floats for something like this though.

The effective cutting angle for the blade is right around 45 degrees. Marking the wedging angle for the blade across its width was simple because I cut a practice dai in pine first, stuck the blade in there, and set my bevel gauge.

The shaving escapement line is cut after the sole of the plane is cut to the angle of the dovetail you want. I’m pointing to the angle with the pencil in the photo above. Let the wood find the angle for you. If you were to cut it before the sole angle the mouth of the plane would be too open on the inside.

Here is a shot of the kanna I modeled after showing a critical detail. The knicker iron is not set evenly into the block, its shallower at the cutting edge and lays in progressively towards the top of the plane block to provide a cutting relief angle. Its also not even side to side, the blade skews outward just like how a marking guage blade is set up so that it pulls into the work a bit and helps keep the fence tight to the work. Its an easy to miss detail!

Here’s the cut for the shaving escapement, and a 1/4″ starter hole for the conical shaving escapement.

I lack carving gouges for this sort of thing, but do have a conical carving thingy, what are these called? I don’t know but it worked a treat.

With all the major cuts made I match drilled the body and fence for the fence adjustment hardware.

Lots of fine tuning to get a simple looking plane like this to work properly. There’s no lateral adjustment of the blade, just sharpen it properly for an even projection from the sole. Getting the knicker iron lined up with the outside edge of the cutting iron is also critical, they both sit very slightly outside the edge of the block.

Really simple fence hardware, some long machine screws and whatnot. The little adjustment knobs that hold the fence took a while to cut, file, and tap.

Works great! I could not be happier with the blade quality after cutting with it a bit, the edge holding is there. It was easily a week of work to make this guy starting with chopping the charcoal, it makes the antique one you can find for sale online look like a really good deal!

If anyone is interested in making one of these I can post the rest of the image set I took of the original I copied and some dimensions.

There’s easy sliding dovetails in my future.

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.