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.

Laminated Molding Plane Irons

A couple of months ago someone dropped off an old molding plane in my shop that was missing the iron and wedge. A plane missing its iron is like a book torn in half, so unsatisfying…

Lie-Nielsen happens to make tapered molding plane iron blanks from solid 0-1 steel that you can buy annealed and ready for profiling for not too much money, but how about making your own by forge laminating some tool steel? For anyone interested in Japanese tool blacksmithing forge welding is an important skill, one that I don’t really have ideal conditions to practice, having to set up my forge in the out of doors. But I’ll be damned if life just goes on and on without giving it a try.

For the main body of the iron I used 3/16 mild steel. Hollow and Round molding planes are generally made as matched sets, so it makes sense to make two irons at a time. Hence a way of cutting the steel to rough shape and pre-forged dimension with little waste.

I plunge cut the middle with an angle grinder and finished by hand with a hack saw. If you don’t have an angle grinder you could just leave a little extra room on the reigns of the iron and cut a slot wide enough to get the hacksaw blade in for the vertical cut.

The tool steel I used was forged down from an old file to about 1/8″ and tapered on the back end. Any less than that and I found that the tool steel in my lamination tended to become quite uneven. I tried so, so many times to get the tool steel to stick properly after fluxing with borax to the mild steel and stay in place while bringing up to welding heat in the forge. Its tricky, to say the least. Luckily I have a MIG welder so just tack welded a tiny spot in the back, brought up to fluxing heat, and separated the pieces enough to get some borax in there, then back in the fire for welding heat. The mating surfaces had previously been ground bright and clean.

Previously I had been dubious about my ability to get a good welding heat, its hard to judge outdoors, even with a big piece of plywood casting shade. Using hardwood charcoal I practiced forge welding mild steel back on itself, and found that yes, that shit gets hot enough to melt away and form little bloom nuggets around the tuyere. The key for me was making a (relative) large fire where I had clearer oxidation and carbonization zones. Judging when the steel is hot enough…still a matter of experience.

Three welding heats and two forging heats to get down to thickness and taper from 3/16″ at the cutting edge to a little less than 1/8″ at the back. Mild steel is much more forgiving of cold forging than tool steel, and the reigns of the iron draw out quite a bit. Get them as close to finished dimension as possible! The lamination I didn’t forge on edge, just squashed out like a pancake and cut, ground, and filed to shape.

The laminated part will warp a bit during quenching, and some of it will come out after tempering, depending on how hard you are going to leave the steel you might consider forging in a little bit of the opposite bend before quenching. A decent ura would help too, that might come later for me.

I like using old files for tool steel, you can find them really cheap in junk and antique shops. That said, now that I’ve met with some small portion of success forge welding I went ahead and bought a stock of 0-1 tool steel 2″ wide by 1/8″ so that I could practice with steel of consistent properties, and it saves a good bit of work and charcoal compared to forging files to the right shape and thickness for lamination.

I need this sign, my shop is a slow work zone.

Indeed it was a very slow work zone out on the road, nobody was there.

I like “Wooden Planes and How to Make Them” quite a bit, but you won’t know shit about how a proper side escapement plane is made by reading only that one book. Larry Williams DVD “Making Traditional Side Escapement Planes was great, and lists all the requisite molding plane iron dimensions for any give size of plane.

If I get the chance I’ll make some sen and the plane blade and knife for a Japanese dovetail plane I’ve wanted to put together ever since trying one out at Mark’s. Easy sliding dovetails in my future!

Trammel Points for Circular Work in Carpentry

Need to lay out an arch? You’ll need some trammel points and a beam of sufficient length. After a survey of what was available to buy I decided to make my own.

Why three? Most simple arches can be formed with just two. Approximations of ellipses, the so called “bricklayers arch” similarly use two. If you want to draw true ellipses though, you’ll need three. So go ahead and make three and thank me later, haha.

I recently had a chance to read both Hasluck’s “Carpentry & Joinery” and Collings’ “Circular work in Carpentry and Joinery”. They’re both excellent texts and Hasluck’s stuff is in the public domain, so go treat yourself to a bit of free knowledge if you care to understand a bit better what modern carpentry has been reduced to.

The wedge and point sit in a gentle sliding dovetail, which keeps things from popping out of place. Both are contained within the long grain of the vertical clamp side. I used a thread box to cut the threads for the screw and tap the threads. Really, they’re just made out of a little scrap I had lying around. The points are 1/4″ mild steel.

I was asked recently to cut an arch-top molding for the inside of an entryway door. Its no small feat, really the domain of specialized shaping machines in custom mill shops. I’ve seen a tilting router setup that can do some decent profiles in a home shop, but how did the carpenters of old make this stuff before shapers and profiled knives? Radiused hollows and rounds of course. A look at carriage makers planes is very instructive.

The layout for the molding I have to cut wasn’t one listed in the books I have, but follows a standard model that I was able to deduce once back home in my shop. Fun stuff!

As an aside, have you ever noticed how much Mentos “The Fresh Maker” candy look like bi-convex go stones?