Knockdown Bookcase

After carefully laying out the shelf locations, use a dado stack (set at a 5 degree angle) and the saw’s miter gauge to cut the angled dados.

The Arts & Crafts movement was part of an interesting social change in America – the advent of mail-order purchases. Catalogs from Sears, Roebuck and Co. and Montgomery Ward were all the rage, and many companies took their cue and offered their wares for sale through catalogs rather than set up expensive retail establishments throughout the country. While it was a great idea, it raised a difficult problem with furniture. The majority of space in any piece of furniture is air. While air is very light, it’s also bulky and expensive to ship. So furniture makers perfected a style of furniture that continues today – knockdown furniture. Finished disassembled, the furniture could be shipped flat, then assembled by the owner. Through-tenons with tusks were the turn-of-the-20th-century answer, while hidden cam-locking hardware is the answer today.

Slanted Construction
This project is actually a very simple bookcase made challenging by slanting the sides. Many of the knockdown bookcases had straight sides, but why do things the easy way?

This simple scrap-wood jig made angled mortises a fairly simple task.

Start construction by preparing the panels for the sides and four shelves. If you aren’t fortunate enough to have oak that’s wide enough to make your sides using a single board, glue up the shelves or sides using two boards, but make sure the joint falls in the center of the finished panel. This is less important on the shelves; but since the sides come to a peak at the center, the joint becomes obvious if you’re off the mark. Also, you can cut the top and bottom shelves to length, but leave the two center shelves long at this time. When the through-tenons are cut and fit, you can measure for the exact length of the center shelves.

Critical Pencil Lines
With the sides prepared, lay out the shelf locations, mortise locations and the overall shape in pencil on one of them. To allow you to do a minimum of angled or beveled cutting on the pieces, the shelves all fit into 3/4″-wide by 3/8″-deep dados cut at a 5° angle in the sides using the table saw. Because of this, the location of the shelves actually falls at an angle on the sides. A 1/16″ difference in shelf height one way or the other won’t dramatically affect the use of the bookcase, but you must make sure that the dados are cut at the same locations on each side.

With the sides clamped together and mounted in my vise, shaping the sides simply took some sanding and planing.

If you happen to have a sliding table on your table saw, you’re in great shape. Most people don’t, so the next best option to cut the angled dados is to use your miter gauge. If you don’t have a substantial wooden fence attached to your gauge, now is a good time. A fence that is 18″ to 24″ long and about 3″ high will work fine. You’ll need to determine which way to orient the sides on your saw depending on the way the arbor of your saw tilts. With some of the cuts, the majority of the side will be supported by the miter gauge, and you can use your rip fence to guide your cut. When the larger section of the side will be between the blade and rip fence, this is an unsafe cut. The board can twist and bind against the blade and cause a kickback. Move the rip fence out of the way, mark the sides and make the next cuts with only the miter gauge fence. With the dados complete, swap the dado with a crosscut blade, and bevel the bottom edge of each side at that angle.

Angled Mortising

A close look at the wedged through-tenons shows the recess behind the side that allows the wedge to pull the sides tight.

The next step is the through-mortises. For these to work correctly, they also need to be cut at a 5° angle, and they must fall directly in the dados you just cut on the saw. You could cut them by hand, but the 5° angle is tricky to maintain. You could also set up a mortiser to do the job, but I got a little smarter and came up with a router template.

By using a piece of 1/2″ Baltic birch with a strip added beneath one end, I made a router template that would make cuts at a 5° angle. It takes some rearranging of the guide for the different cuts, but the results work rather well.

Careful layout lines are critical here. To make the 5° ramp, I used a scrap piece of 1/2″ material for the back strip, nailed to the template 14″ from the end. Check this dimension carefully on your materials to get as close to 5° as possible.

The rest is fairly simple. Check the offset on your router template guide from the bit, and add this to the 3/4″ x 2″ dimension for the mortise. Mark that size on the template and use a drill and jigsaw to make a square hole.

Clamp the template in place over the mortise locations and cut your through-mortises using two or three depth settings. Depending on the router bit you’re using, you may want to use a backing board behind the side to reduce tear-out. I used a jigsaw and chisel to square up the corners.

Shaping up the Sides
The next step is to cut the sides to their “spade” shape. I used my band saw for most of this work, but used a jigsaw to cut the radii under the top shelf and the arch at the bottom. Cut a little wide of your layout lines, then clamp the sides together, aligning the sides by the shelf grooves on the inside surface. Plane and sand the sides to matching shapes.

Fitting the Through-Tenons
Now it’s time to fit things together. Start by checking the fit of your shelves in the dados in the sides. Mine were a hair thick, so I was able to run them down on the planer to make an almost-perfect fit. Check the width of the bottom shelf against the width of the sides at the shelf location, now that the sides are shaped. Rip the shelf to size. Next, fit the shelf into the dado and, from the outside, mark the tenon location through the mortise on the end of the shelf. Remove the shelf and mark off the 2″ length of each mortise, then head for the band saw again. The width of the tenons is the critical cut. The shoulder of the tenons should be neat, but that edge is buried in the side’s dados, so it doesn’t have to be perfect.

With the tenons cut for the bottom shelf, fit the shelf and sides together. You want a snug fit, but not too loose and not too tight. A chisel, file or rasp and some sanding should do the job. Take your time and get it right.

With the bottom shelf fit, check the dimensions on the top shelf, mark the tenons and repeat the fitting process. When that task is complete, fit the two center shelves and slide them into position. These shelves are designed to be left loose, but if they slide a little more than you like, a nail through the side into the center of the shelf will make a permanent solution, or you can drive a short wedge into the joint under the shelf for a temporary fix.

Tusks and the Home Stretch
To hold the top and bottom shelves in place – and the whole case together – disassemble the case and mark the 3/4″ x 3/4″ through-mortises on the shelf tenons as shown in the diagrams. I used my mortising machine to cut these holes. Another option is to use a drill press to cut the mortises and then square up the corners using a chisel.

Reassemble the case, then cut the eight tusks. Appropriately, the tusks should seat with their center at the shelf tenon. Fit the tusks as necessary, and tap them into place to make the whole case rigid. Now take it all apart one last time and sand everything to #150 grit.

For a finish, I used a simple dark-colored gel stain, wiping off the excess until I was happy with the depth of the color. I then top-coated the case with a couple of coats of lacquer.

The nicest thing about moving this bookcase is that after you knock out the eight tusks, everything fits in the trunk of a compact car. PW

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David Thiel is a senior editor at Popular Woodworking magazine.