Treasures And Trinkets
Home project: This sleek, modern design goes well just about anywhere, but the overall design can be easily adjusted by changing some details. A different style of lid, adding some texture to the curved sides or adjusting the proportions of the box will all work wonders when it comes time to customize your box.
The curved sides of my box were created using a table saw technique called ‘cove cutting’. This method involves running a board diagonally across a table saw blade to form a cove down the middle. By changing the angle of approach you can alter the width of the cove. If you’re really adventurous, you can even modify the symmetry of the curve by tilting the blade. If you don’t want to simply experiment with the setup geometry, and see what you end up with, the easiest way to work out the details is to use one of the many calculators found online. Search for ‘cove cut calculator’ to locate the online utility that works best for you. The calculator I downloaded determined that the angle of approach needed to be 20° to create the 5″ wide by 3/4″ deep cove required for this project. This calculation is based on the assumption that a 10″ diameter saw blade is being used to remove the material.
Get started by breaking out a 5-1/2″ wide by 24″ long blank for the sides. After machining the cove, I will rip the workpiece in half, creating two narrower boards, which can then each be cut into two parts. For my project I chose a 1″ thick piece of spalted maple. Your next task is to set up the table saw to complete the coved profile. After raising the blade to a height of 3/4″, use a framing square and a mitre gauge to lay out a path that intersects the leading edge of the saw blade, at the required 20° angle. Temporarily mark the path by laying down a strip of painter’s tape along the edge of the square. After removing the mitre gauge and square, position your first guide board in front of the tapeline and clamp the ends securely in place. When you do this, leave a 1/4″ gap between the board and tape to allow for a lip on the edge of the workpiece that must remain flat to support the workpiece. Lower the blade below the surface of the table and use your blank as a spacer to position the rear guide board. After clamping this board in position, remove the tape.
The first pass is completed with the blade raised to a height of approximately 1/8″. Switch on the saw and slowly guide the blank over the spinning blade with push sticks. After completing the first pass, rotate the board end for end and make another run, ensuring the cove is centered on the workpiece. Raise the blade in 1/16″ to 1/8″ increments and repeat the two-pass process until the cove reaches the completed 3/4″ depth.
If the saw motor begins to labour at any point, slow your feed rate or raise the blade in smaller increments. Repeat the last pass a few times, without raising the blade and ensuring even pressure is applied to the workpiece, to make sure you have the smoothest surface possible.
After completing the last pass, remove the temporary guide boards and set your fence to rip a pair of 2-5/8″ wide strips from each side of the blank. When you make these rip cuts, the cove needs to be facing up.
The bottom of the box will be seated in a 1/4″ deep slot located 1/4″ from the lower edge of the side panels. It’s much easier to complete these slots before the sides are cut to length. I used the table saw to create my grooves, but a router table could also be used. Be sure to know what material you’re using for your bottom panel now, so you can size the groove appropriately.
After forming the grooves for the bottom panel, you’re ready to cut the sides to length. This task is completed with the saw blade tilted 45° to form mitred ends. Be sure to use a length stop to ensure opposing sides are exactly the same length.
Cove Cut Setup
With his mitre jig set 20° off of parallel from his saw blade, Campbell used his carpenters square to position some masking tape. The blade was able to cut part way through the tape when raised. The initial guide board will be positioned parallel with the tape, but about 1/4" back from the furthest point the blade cuts when it’s raised to the final height.
Making the Cut
Now that the two guide boards have been clamped in place, a series of cuts can be made to slowly create a cove.
Campbell adheres the stencil to the glass then gently applies the etching cream over it with a popsicle stick (above). After leaving the cream on for about 10 minutes, it can be cleaned off, to reveal the final pattern (below). (Top photo by Rick Campbell)
Once the top has been assembled, use your table saw to cut rabbets in its underside. Leave 1/8" of material intact, above the rabbet.
Campbell cut and applied adhesive-backed felt to the inner surface of his box, but you could also flock the interior. Either way, select a colour that blends nicely with the wood and style of your box.
I decided to go with a piece of 1/8″ thick veneered maple plywood for the bottom panel because it’s more stable than solid wood. This means problems associated with seasonal expansion and contraction won’t be an issue. Cut the bottom panel to size and test the fit by dry-assembling the sides. If everything checks out, sand the inner surfaces of the sides and grab a glue bottle. If you’re using a man-made panel for the bottom, gluing it in will add strength to the box, but be sure to not add to much glue, causing it to squeeze out and make a mess. Traditional clamps won’t work to secure the corners of this project because of the curved sides. The easy solution here is to stretch strips of tape over the joints. The tension on the tape will be just enough to achieve a solid bond while the glue cures.
I have never been successful at cutting my own glass, so I avoided the aggravation by having a local supplier cut a piece for me. When buying glass I brought a piece of wood with a saw kerf with me, to check for thickness. Now it was time to etch a decorative design on the surface of the glass. All that’s required to accomplish this procedure is a rub-on stencil mask, glass etching cream, and a popsicle stick. All of these materials are available at big chain craft stores. Begin by laying out some newspaper to protect the work surface from the caustic cream. Next, position the stencil on the glass and firmly rub it into place with the end of a popsicle stick. Peel back the protective overlay to reveal the pattern underneath. Use your popsicle stick to spread an even coat of etching cream on the stencil. Be careful not to touch the mask with the stick because it may cause the delicate film to tear or move. After about 10 minutes, head to the laundry tub and gently rinse off the cream and stencil film. When dry, your etched designed will be fully revealed.
I used a piece of bubinga for the frame, but any complementary wood will work. I started with a 3/8″ thick blank that measured roughly 3″ wide by 24″ long. The first step is to run the blank on edge over the saw blade to form 1/4″ deep slots on both sides of the blank. These slots will receive the glass insert. After this, cut the framing material to width by ripping 3/4″ strips from the edges of the blank. After making any necessary adjustments, cut the strips to length with 45° mitres on the ends. Again, opposing sides must be equal to create square corners.
Apply glue to the corners and assemble the frame with the glass insert in place. Masking tape, applied to the outer edges of the frame, works wonders to secure the joints while the adhesive dries. Once dry, set up the table saw to cut a 1/4″ deep rabbet on the outer edges of the completed frame. The width of these rabbets should be equal to the thickness of the side material at the top of the box plus a 1/32″ allowance to compensate for the felt lining that will be added. The setup for this procedure is going to require a sacrificial board clamped to the saw fence so the blade can run directly against the fence without causing damage to the teeth. When you think you’re ready to go, make a few test cuts on scrap before committing your lid to the saw blade. If everything looks good, mill rabbets on all four sides of the lid. Now for the moment of truth – place the lid on the box to check the fit. Remember, your goal is a slightly loose fit with just enough play to accommodate the adhesive backed felt that will be installed after the finish is applied.
Reaching For the Finish Line
When you sand the rough curved side surfaces, start with 60 grit paper, then work your way through the usual progression of finer grits. If the saw marks are really rough, you can use a curved cabinet scraper. After sanding, tape off the edges of the glass on both sides to protect the surfaces from the finish. I applied a few coats of wipe-on polyurethane to protect the surfaces, and enhance the grain. When working with polyurethane, the secret to a smooth finish is a light sanding with fine-grit sandpaper between applications.
Once the finish is dry, cut some pieces of adhesive backed felt to line the interior and press it into place. Another option is to flock the interior. Flocking is a two-step process that involves the application of an adhesive paint, directly followed by a dusting of felt-like fibres delivered by a flocking canister.