Heirloom Speech Bubble Bookshelves:
These distinctive dovetailed wall shelves feature angles that will challenge your joinery and assembly skills. Charles Mak also shows how to tackle the tricky glue-up in an orderly fashion
I remembered the dialogue shelves handmade by the American furniture designer and maker Geremy Coy when my daughter mentioned about getting some display shelves for her place. She liked the dialogue bubble concept, but wanted a round edge profile as opposed to the square case.
Like Coy, I hand cut the dovetail joints, but I chose a different joinery for the V-sections. I used a floating tenon joint for the large shelf, and, for illustration purposes, a dowel joint for the small shelf instead of the dovetails. And, I changed the frame’s square edge design to a round-over profile.
The large bookshelf measures 200 x 250 x 560mm (rectangular frame) and the small one 200 x 195 x 445mm. Try to make each shelf from the same long board or boards of similar grain pattern so the grain wraps nicely around the shelf.
I used a mix of power- and hand-tools to build the speech bubble bookshelves out of cherry (Prunus spp.). A traditionalist who prefers to go totally unplugged? You can use a hand brace instead of a cordless drill, or up the challenge and dovetail the V-section, too – as Coy did.
Start with the tails
For this project, I gang cut the tail boards in the traditional way using a gang-cutting set-up that I usually use. After laying out the tails, cramp the boards together in a vice with their outside facing out and carry the pin socket lines across the end grain. Then cut the tails and remove the bulk waste in the pin sockets with a fret or coping saw. With the tail board re-cramped horizontally in the vice, saw off the outside half pins. Finally, pare or chop the shoulders and pin sockets clean and chamfer the inside arrises of the tails to avoid crushing during fitting.
Cut the pins
Traditionally, we transfer the tails to the pin boards by scribing the tail socket lines into the end grain and then ‘split the scribed line’, sawing down the pin board. To some, this approach is problematic in two aspects. First, the scribed lines on the end grain are not easy to see. And second, a scribed line is narrow by its very nature and removing half of the V portion of the line can be hard to do.
This time I used the painter’s tape trick, as opposed to splitting the line. First, scribe the baselines on the pin board and cover the dovetail end with coloured masking tape. Mark the pins from the tails by knifing the tail socket lines through the tape and then peeling off the waste tape. Vertical pencil lines are then drawn from the tape edges down the outside face.
To cut the pins, line up the saw teeth against the edge of the tape and saw straight down the board following the vertical line. Remove the bulk waste and clean up the tail sockets as usual. Put some graphite marks on the pins before testing the fit. To see your improvement, simply tap each tail in turn with a crosspein hammer to close the joint. It is safer to trim a pin by paring across it rather than paring down the grain. That being said, if the pins have even and straight grains, I get quicker results by paring down.
Cut the bevels
With the aid of a protractor, draw out the V-section’s joints of the desired angles on a piece of paper. Trust your eyes and use the drawing when the shape and angles look right to you. Then measure or, if you haven’t forgotten what you learned in trigonometry class, solve their bevel angles. Suggested angles are given in the Angles Drawing (see page 63) for the large shelf. I recommend that you list out the parts (e.g. right bottom pin board) and write down their respective cutting angles in a table form and refer to it when laying out the angles or setting the angle of cut. Make some test cuts on scrap to verify your machine settings, if necessary.
Mark the cut-lines clearly on the boards and double check them before you saw. It is a horrible feeling to see your carefully hand-cut pin board ruined due to a cutting or bevelling mistake at this stage. In the last step, remove any handsawn marks or fine-tune the angles where needed with a low-angle plane. If you are making multiple shelves with identical V-sections by hand, you’ll get a quicker and more consistent result by using a skew rebate plane with an angled fence to form or clean the bevelled edges.
Join the V-sections
The joints for the V-sections are all face grain to end grain so glue alone is not enough for a long-lasting joint. I often use Dominos in my furniture building, but, as shown here, a simple dowel joint will work
for this build as well. Cut the loose tenons with the Domino joiner and for the dowel joint, drill holes using a drill jig and a drilling guide. Again, test your angle setup on scrap, if you’re in doubt, before risking your finished workpieces. Dry fit the V-joints and if you make a mistake or need to adjust the fit, you can plug the mortise or hole and redrill it at the right angle or position.
Assemble the bookshelves
Gluing up an irregular piece is always a challenge, more so in this case as the shelves are also dovetailed. It is always worth taking the time to dry fit your work and complete the glue-up with the utmost care. A well-fitted angled piece with no ugly, visible gaps is the calling card of a skilled – and happy – woodworker.
In the final dry fitting, you can no longer hammer the tails to the bottom pin board in the usual manner due to the fragile bevelled edge. To overcome that, cramp a solid block to the bevelled end of the pin board to protect the edge from crushing under the weight of hammering. And, to dry fit the V-section’s pointy joint, use an angled cut-off block as a cramping block.
If all the joints are accurately cut and assembled, you don’t need much cramping pressure to close the pointy joint. You can orient and glue the end grain side (as opposed to the face grain) of the angled block to the piece as I did. Glued this way, the cramping block can be parted off easily with a chisel after the glue-up.
The dry-fitting process served another useful function here: it allowed me to test and fine-tune the proper sequence of assembling. Before you start, study the suggested gluing-up order in the Assembly Sequence Diagram (see page 65) and get all your cramping tools ready. Glue up the shelf section by section. Similarly, plane everything smooth and flush in sequence after each sectional glue-up.
Add the finishing touch
Once the shelf is set, round the outside edges of the frame with a spokeshave. To prevent chattering, use a sharp blade and keep the pressure on the front part (toe) of the tool. Work from both ends or from the front to the back so any breakout will be unnoticeable after mounting. Instead of a spokeshave, you can also round the edges with a bench plane. First, mark the round profile on both ends and draw two straight lines on the adjacent sides to define the round-over. Plane away the waste between the lines and roll the plane sideways as you make the final overlapping, rounding strokes. Finally, smooth out any ridges with a curved scraper or sandpaper.
Mortised-in keyhole hanger plates are the best mounting hardware for this type of wall shelf. Chisel the mortises on the back edges and then finish the shelf with a few coats of boiled linseed oil or any finish of your choice. Finally, install the hanger plates, sign and date the piece, and you are ready to reward yourself with a beverage of your choice. These one-of-a-kind bookshelves are easily recognisable as handcrafted rather than factory-made. They will make a good conversation topic – whether about the shelves or about your craftsmanship – no matter what you end up putting on there!