Cherry Low Cabinet – 1

Hidden Mitered Dovetails

The last cabinet for the series of modular tansu is the low cherry cabinet, which is also the biggest and most complicated of the bunch. The cabinet is nearly 6 1/2′ long (1980m), and 30″ tall (765 mm) with the base. The original cabinet that I built that inspired this one was considerably smaller, so when I was designing this cabinet with it’s larger scale I considered lots of different joinery options that seemed appropriate for such a massive piece. In the end I stuck with the original design and decided to go with hidden mitered dovetails for the corners of the main cabinet (which is also what the clients preferred), but for the partitions and shelves I opted for wedged through tenons in as many places as practical to add a lot of mechanical joinery and solidity.

Below is the inside of the top panel being glued up from two boards. I would have preferred to use material without any sapwood, but was unfortunately not able to source any completely clear boards in the width that I needed. So I strategized and oriented any sapwood towards the interior of the cabinet where it won’t been seen. So what you’re looking at below will be the inside surface of the top of the cabinet.

The Petty Work saw is way too small to handle crosscutting such massive panels, and while I had dreams of setting up some sort of extension bed to accommodate this project, in the end it was simplest to just go old school and cut the panel ends square and true with a circular saw and guide.

In the picture above you can see that I doubled up the top and bottom panels and cut them simultaneously in an effort to make them as identical to one another as possible.

With the panels cut to length I started handplaning the interior surfaces in preparation for laying out the hidden mitered dovetails. At this point I only planed the interior of the top and bottom panels, since those were the panels which would end up with dovetail pins. Planing pins after the fact has the effect of loosening the joinery so I always plane those panels ahead of time.

Here’s the first end after laying out the dovetails. I went with a perfectly even arrangement for the width of the pins and tails to maximize strength.

To get a truly even spacing I marked the dovetail slope relative to the center of the dovetails’ thickness.

With one end layed out I transfered the layout marks to a story pole to speed up layout for the other three ends.

Here’s another end after marking the layout using the story pole. The finished layout is much clearer without all the extra reference lines that were visible in the first set.

From there I started cutting the joints using a handsaw, aiming to split the line as best as I could. I don’t often use handmade saws, but this is a special project, so I busted out a handmade ryoba saw that was sharpened by Takijiro-san a while back. It was a joy to use.

Then to knock out the waste I first used a drill and auger bit…

….followed by a router to accurately cut down to the bottom depth. I used a bit with guide bearing which prevented any risk of undercutting.

For the remainder of the waste I used chisels to chop and pare the pins to their lines.

The final step was to very accurately trim the shoulder using a chisel and maple paring block that I trued up on the jointer.

Once the pins were cut on the ends of the top and bottom panels, I brought in the shorter end panels to mark out the tails.

To mark out the tail locations I simply used a mechanical pencil marking directly off of the pins.

From there, cut out of the tails was pretty much the same as for the pins, starting with handsawing followed by drilling, but this time before routing, I chopped out the top portion of waste to the shoulder line.

Then I used the router and bearing bit to clear out the remainder of the material and establish the final depth.

And once again used chisels for the final clean up down into the corners of the tails.

Now onto the real challenge of hidden mitered dovetails; trimming the miter.

For the first set of tails that I cut, I used a kiwa-ganna (Japanese corner cutting plane) to trim the miter with the aid of a mitered planing guide. You can see the planing guide clamped to the end panel. I aligned the guide to the rough cut miters on each edge of the panel.

Then using the kiwa-ganna ,I planed away the corner until a miter started to form.

It had been a while since I cut hidden mitered dovetails, so I took the first set nice and slow, cutting the miter by hand using just the kiwa-ganna. But once I got rolling, I switched to rough cutting the remaining miters using the circular saw to speed things up.

I also modified a different kanna to make parining the miter a bit cleaner and less troublesome. The kiwa-ganna works but you have to be careful about not digging the corner of the plane into the end grain of the tails. With the kanna below, cut with a large 45 degree bevel that meets exactly with the corner of the blade, truing the miters becomes much easier.

The large bevel can cleanly butt right up to the end of the tails, so in combination with the mitered guide, the plane has much more support and it’s easier to focus on cleanly paring the miter.

(The plane I modified for planing the miters was my first ever kanna, which I setup under the guidance of Yann Giguere. It’s been a really versatile plane, and I had previously modified it for cutting some 45 bevels for a ceiling project.)

With the miters cut so that just a little bit of fat remained on the layout lines, I started trial fitting the joints. Below is the first corner coming together.

And here is one end of the miter after the first test fit. Despite how difficult these joints look, they are surprizingly straightforward to get to this point. I find it’s the final adjustments that are hardest part.

For final tweaking of the miters I started by truing up the corner joints using a paring chisel and 45 degree paring guide.

Here’s another corner after a bit of paring and adjustment. Getting close to the finish line.

Once all the dovetails were cut and trued up to the 95% mark I set them aside in prepartion for the other joinery, with the plan being to do the last bit of adjustment after fitting the remainder of the cabinet parts. To protect the precious miters in the meantime I attached some cutoffs using screws driven into the end of the tails. With this kind of blocking technically the miter is still exposed but the thickness of the screwed on cutoff adds a lot of protection.

That’s it for the hidden mitered dovetails, but there’s still a lot more to go for this cabinet. More on that in the next post.

Thanks for reading.