Making The Kanna Chair, Pt.2

Where we left off, with the spindles drilled to their appropriate angles.

This is the second and last post in a series about the making of the Kanna Chair.

Moving on from the last post, the next steps for the chair involved seating the legs, carving the seatpan, and final assembly.

I mentioned earlier that the leg design I went with didn't require a lathe, but it still required a circular shape and therefore a woodturning workaround. Each leg must slide into a tapered hole cut into the seatpan, so the end of each leg had to be a tapered cone. To achieve this strange shape without a lathe I purchased a leg tapering jig which ended up being just a beefed up pencil sharpener. The way it worked was by sticking the leg in and spinning it against the blade until the leg was "sharpened" like you would a pencil.

The tapered cone shape I was aiming for, just like a pencil.

A convenient part of making my legs octagonal was that I could attach a socket bit to the end of the leg and hook it up to my drill, allowing my to spin the legs at high speed into my tapering jig, making quick work of the legs. Underneath the seatpan each hole was drilled with a tapered drill bit, set to the same tapered angle as the tapering jog for the legs.

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The beauty of the tapered leg is that the more weight you put on the chair, the more the legs get pushed in and locked against the walls of the hole, so even if the legs shrink as they dry or the glue weaken over the decades the shape keeps the chair rock solid. It's one of those things thats easy to overlook but clearly a technique that developed over centuries of trial and error.

The legs test fit into the seatpan after tapering. I was very pleased with how strong and solid the felt.

With the legs done one of the last steps was to carve the seatpan. The traditional way to carve it would be with a scorp and chairmakers adze, both of which are specialized and rare tools that I don't own. Instead of buying the tools to only use them once, I decided to get creative with my approach. I used a trim router to cut channels into the seatpan at various depths before carving, that way I could keep track of exactly how deep I was carving without having to stop and manually check my depth every few seconds. I haven't seen this in any books but It worked really well and I would certainly do it again if I was power carving again.

The grooves cut by the router tell me how deep I've carved as I start power carving. You can see in the top left where the grooves are gone and the depth is final

I used an angle grinder with a powerful carving bit to hog off material, which gave me a result I was very pleased with. It left a lot of deep scratches which I shaved down with with a curved card scraper before proceeding to sanding. A well sharpened card scraper can make very quick work of even the deepest scratches.

The card scraper made quick work of the rough surfce left my the power grinding.

The final shape of the seatpan. In hindsight I would have made the curves much deeper and dramatic.

At this point everything was done and just needed to be assembled, which is not as easy as a regular furniture piece. Since there are almost no flat or square surfaces to attach clamps to, keeping pressure on the legs during the glue up required more creative solutions. I decided to make tourniquets out of rope and spare pencils I had, and after testing how much pressure I could create I was sufficiently convinced it was the best way to tackle glueing up the chairs.

One of the tourniquets in action. By twisting the pencil the legs are pulled together as the glue dries, and once tight enough the pencil can be held in place against the spindle itself.

At this point in the project any mistake would be extremely difficult to fix, and having to re-make any of these highly shaped pieces would have been a huge setback. Despite the complex angles, the dozens of different parts spread between two different chairs, and the irregular shapes everything came together without a problem. The joints felt tight, nothing was off of broken everything went the way I imagined it.

The final product without wood finish. I love the octagonal shapes and how they catch the light, I can see myself working with them more in the future.

And that's it. Next time I make a chair I'll try a deeper seatpan, and test out armrests or even drawers and other fancy elements I've seen on old American windsor chairs. Thanks for following along and if anybody has any questions about some of the technical parts of the chair I glossed over feel free to comment or reach out.

My next post will be covering a credenza I'm working on with sliding doors, handplane finishes and textured adze work, so stay tuned for that.