MAKE THIS TRAY TO MASTER THE DOVETAIL KEY
Besides being handy, this tray looks graceful, mainly because the sides flare out. The obvious way to connect such corners is to miter them; however, glued-up end grain corners are weak and need some mechanical reinforcement. To enhance the elegance of the joinery, dovetailed corners would represent the ultimate silhouette and strength. On the other hand, cutting dovetails on such compound-angle corners requires experience, skills, patience and good sharp hand tools. Keep reading for a solution to simplify the task by constructing the tray using dovetail keys with a few straightforward steps, easy set-ups and simple jigs.
First, cut all four sides extra long. Then tilt the table-saw blade to ±30° and rip both edges parallel to each other to end up with parallelogram-shaped ends, as shown. (The blade guard has been removed for clarity.) To be on the safe side, the sharp edge in contact with the rip fence should always be pointing up so it won't wedge under and jam, which may cause a perilous kickback.
Applying bevel on table saw.
The compound miters can be cut either with a table saw or a basic miter saw. Let's start with the miter saw. Drop one side on the miter saw bed (or extension, as shown), making sure the lower edge sits perfectly flat on the bed and the upper edge is leaning along the fence. Mark the bed or note the lower front edge distance.
Measuring for compound miters.
Repeat the process at the other side of the blade. Now clamp a straightedge to those marks, making sure it's parallel to the miter saw fence. Swing and lock the saw 45° to the right and cut one end of the four sides (left photo). Then swing and lock the saw 45° to the left and clamp a stop block to cut the opposite ends to uniform lengths.
Image left: Cutting compound miters on miter saw. Image right: Compound miter cradle.
The set-up at the table saw requires a simple cradle, which is fastened to the miter gauge set to 45°, and a filler block. As shown, the cradle is nothing more than two boards fastened parallel to a bottom. The filler block should perfectly fill the gap between the tray side sitting flat on edge, as mentioned above, and tucked in the cradle opposite the lower corner, with the top edge leaning against the filler block. Cut one end of the four sides.
Image 1: Cutting compound miters on table saw. Image 2: Cutting compound miters on table saw.
To cut the other ends, move the miter gauge to the right side of the blade and turn it around to the opposite 45° angle. For consistency, add a stop block as shown.
Cutting compound miters on table saw.
This photo shows two perfectly matched sides, square according to the drafter's triangle, temporarily standing against heavy steel measuring blocks for the photo.
Preparing to glue miter
Gluing up such an assembly can be a challenge, but you only need to surround the perimeter and add weight. Years ago, I made this assembly jig, which is nothing more than a piece of 3/4" plywood to which I added a removable melamine board so the glue won't stick to it. I notched two sides for locking clamps to reach inward when necessary and added external melamine shoulders to contain assemblies. For this project, I temporarily added and clamped two more Melamine boards onto the base to confine the perimeter of the tray. Once it’s glued, you only have to add one more melamine board, or any other slick material, on top as well as weight to keep the joints firmly closed. I like to use plastic jugs filled with dry playing sand (±18 lb each).
Image 1: Glue up in assembly jig. Image 2: Applying weight to secure glue-up in place.
To raise the work to a comfortable height, I clamped my 12" tall homemade MFT benchtop table onto the workbench. Clamp the dried frame onto your work surface, one corner approximately centered as well as flush and 45° to the edge. Mill two holding blocks mitered to the same angle as the tray corner, which you can find with a protractor or a bevel square, drill a through-hole in each one close to the mitered end, and clamp them to each end, even with the front edge of your work surface. The result of all those steps is shown in the image below.
Clamping frame to work surface.
You will need a jig to guide your router to mill dovetail slots into each corner of your tray. The jig is clamped to the mitered end of the holding blocks through the previously drilled holes. When done, outfit your router with the appropriate guide collar size according to your own jig as well as a dovetail bit. For the size of my tray, a 3/4" 14° dovetail bit was the ideal choice.
Image 1: Clamping router jig to work surface. Image 2: Dovetail bit and template guide installed in router.
This is what the first dovetail slot looks like. The left photo shows the required location marks that should be established at one corner before setting up the jig. The right photo shows register marks added to both ends to standardize the slot locations of the four corners.
Image 1: Routed dovetail slot. Image 2: Slot locations marked by pencil.
At this point, the four corners are slotted and ready to receive dovetail keys that will mechanically secure the joints. At the table saw, take your time to mill a slip-fit long key by tilting the saw blade according to the degree of your own dovetail bit.
Image 1: Dovetail keys on frame. Image 2: Cutting dovetail keys on table saw.
Glue all the dovetail keys in the slots and let the glue dry. The next step will be sawing the protruding parts and fine-tuning each end with a sharp chisel. Once again, it pays off to take your time to trim such end grain adequately.
Image 1: Inserting dovetail keys in slots. Image 2: Flush trimming dovetail keys.
The last step is to plane the top and bottom of the tray even and straight. It's also a good time to sand all surfaces and perhaps round over the top outside sharp edge with the plane, a file or sandpaper for a soft touch.
Planing bottom of tray.
For the bottom, mill and glue a few boards. When done, sand and round over the perimeter. To center the bottom within the perimeter, I found that using four standing squares and a ruler was simple and effective. Once it’s centered, carefully mark the screw locations by sighting the side ends. You don't want screws to poke through!
Centering base on frame.
The screw holes along the long sides of the bottom board must be elongated to allow for wood movement, which significantly happens only sideways. This task can be done by tilting the drill bit back and forth while drilling through the bottom only. No glue allowed here, since wood movement could split the bottom! The end screws require straight holes, and a dab of glue can be applied close to the screw holes only (1" to 2").
Image 1: Drilling elongated holes to allow for wood movement. Image 2: Installing screws.
You may want to let the wood speak for itself by applying a clear finish (oil being my favorite), which will emphasize each corner dovetail key and perhaps raise your pride to a higher level by demonstrating your new woodworking skills throughout your latest project. You can make it!
Image 1: Applying finish. Image 2: Close-up of keyed dovetails.
Serge Duclos started woodworking in 1972 after purchasing his first house. He soon found it was a way to relax from the stress related to his job as a human resources professional. Since retiring in 2004, Serge continues to enjoy his pastime and to update his bilingual woodworking blog http://atelierdubricoleur.wordpress.com with his projects, as well as his tips and techniques.
Tools for This Project
Spring Clamps & Pliers Set
Incra 1000SE Miter Gauge
Kreg Precision Miter Gauge System
Veritas Precision Square
Veritas Detail Flush-Cutting Saw
Osmo Polyx Satin Hard Wax Oil
Dripless Glue Bottles
Carbide Countersink Drills with Low-Fr...