A Carved Tea Box

A few months ago, I started experimenting with making a wooden tea box. Unlike a jewelry box, a tea box is something you share with your friends when they come over to visit. I wanted to have an ornate design that used contrasting woods with prominent grains. I also wanted to see if I could use my CNC to carve the piece.

The design I came up with uses a CNC for all the joinery and designs. It is relatively simple to make if you have access to this kind of machine. I will note the obvious - a CNC machine is not needed to make a simple box. This is just the approach that I took in this project, but dozens of books and how-to guides illustrate how to make boxes using traditional construction techniques. A CNC machine allows you to replicate the project quickly with minimal labor. The total carving time for the project was about 2.5 hours, with about 30 minutes required to sand and adjust everything for a solid fit.

Since this was done using an XCarve, the design files are available through Easel on the Instructables website. Setting up an account is free. There are two versions of the project:

1. A version with separate carves for the lid and bottom of the box.
2. The version described in this Instructable where the box is assembled, and the lid is cut off the box using a table saw.

As a CNC project, this was a good skill builder. It involves:

1. Double-sided carves
2. Dog-bone mortises
3. 3/4 tendon joints using combines of simple geometric shapes and careful alignments of the cuts
4. Making interlocking interior pieces
5. Aligning and squaring the box and adding the hardware

Let's get started!

• 12" x 8" x 0.5" - lid piece with a strong grain and lighter color. (Canarywood)
• 17" x 6" x 0.5" - for side pieces (Cherry)
• 26" x 6" x 0.5" - front and back (Cherry)
• 12" x 8" x 0.25" plywood for the box bottom
• 26.5" x 5.5" x 0.25" for wood insets (Red Maple)
• Hinges for a jewelry box (for example, Highpoint small box hinges 23mm x 22 mm pair)
• Latch for a jewelry box (for example, Highpoint truck draw catch)

Finishing supplies - sander, sandpaper, tack cloth, spray finish of your choice (I love shellac).

The critical element in the design is the carved box lid. There are two parts to this:

1. An ornate geometric design in the top form the art library in Easel
2. A "floating lid" surrounding the design to accent the carving.

One of the elements that make the project pop is the Canary Wood. Using a workpiece with a light tone with a prominent grain paper helped accentuate the piece.

The box lid was carved in a single pass carve using a 1/8" bit on my XCarve. The geometric design is inset by 0.15". The depth of the lip is 0.27". Since the wood thickness should be 0.5", the final thickness around the lip after the carve should be about 0.23". The lid will fit comfortably inside a groove with a thickness of 0.25".

Of course, you should pick any design you like for the box top. The design dimension of a 5" circle seems to fill the lid without feeling overcrowded.

As a final step, the CNC will carve through the wood around the lip to release the piece from the surrounding wood. The final dimension of the piece after the carving is 11.3" x 7.2". The total time to make the lid, including the lip, was 1h 15m.

I used a hidden mortise and tenon joint to hold the project together. The front and back pieces have tenons, and the side pieces have mortises. You could certainly use other types of joints in this project. I opted for this particular method because it can easily be done using the CNC.

On the sides, there are two sets of mortises. The bottom set is 2" tall x 0.35" wide x 0.35" deep. The top mortise is 0.75" tall x 0.35" wide x 0.35" deep. All of the mortises are inset from the edge of the wood by 0.5". We will create a matching tenon on the front and back pieces in the next step.

Because we are using a CNC machine, we have to modify the mortise holes slightly. CNC machines cannot cut sharp interior corners because they are using a rounded bit. To accommodate wood with rectangular edges, you need to cut "dog bone" patterns to slightly expand the rectangles in the corners. The good news is this function is readily available in most CNC software. You draw the piece you want to fit and use the Dogbone generator to make the right piece.

The front and back pieces of the box are carved from 26"x6"x0.5" pieces of cherry. Cutting this piece was the most complicated step because it involves a two-sided carve. The carving time on my machine for these two pieces was about 9 minutes for the outward-facing side and about 30 minutes for the side of the wood that faces inward.

To make the joins holding the box together hidden, I used a 3/4 hidden tenon. I've included a Fusion 360 drawing and a few photographs to illustrate how this works. There are shoulders on three sides of the tendon, with the remaining side flat with the board. Carving this joint on a CNC machine involves removing the material from the outward-facing side of the wood and then flipping the piece over to carve the grooves that hold the top and the bottom. After carving these grooves, the CNC cuts the outline of the side pieces.

The design has two alignment holes from the wood into the wasteboard on the workpiece's extreme left and right sides. These holes are a the center of the carved piece. Using two pieces of dowel 0.25" in diameter and about 0.75" long, you can flip the piece over and keep it precisely in the same spot. Make sure to use the previous location of the workpiece when you do this flip rather than resetting the workpiece zero.

Designing tenons on the CNC is relatively easy. The piece is just a union of the two rectangles placed at the correct locations. Given the 0.35" depth of the mortise, I conservatively decided to make the tenon 0.25" long. Because I cut this piece with a CNC machine, I used a chisel to square the corners of the tenon. It only took a few strokes to sharpen these corners.

I did my first experiments with this technique on the router table instead of the CNC. I adjusted the fence, so the bit was flush against the wood that was not part of the tenon. I slowly removed the wood on the front side of the tenon with multiple passes, carefully raising the bit after each pass. I check the fit to make sure the mortise and tenon fit snugly together.

The tolerances on mortise and tenon joinery are tight - perhaps 1/64". The best way to approach this is to use your big machines to get close to the proper dimensions and use a rasp to remove the remaining wood for a perfect fit. When you use the rasp, make sure to keep it exactly parallel to the end of the part of the wood that will be flush with the sides.

Once the tenons fit the mortise joints, do a final test to make sure everything fits perfectly together. The box's lid and plywood bottom slide into the grooves. You may need to do some light sanding on the pieces to make sure they fit comfortably in the groves.

Carefully sand and test fit all the pieces together to check that everything is tight and flush.

When you are ready, place glue on the tenons and in the mortises. I used standard woodworking glue for the joints. The lid and the base float freely and do not require glue to hold them in place. Starting with a side, place the front and back piece into place. Slide the lid and box bottom into their grooves, then glue the remaining side into place.

At this point, it is critical to make sure the box is square. You can either measure the diagonals or use a carpenter's square to get everything perfectly aligned. Once you are satisfied, then apply clamps to hold everything together tightly. After applying the clamps, recheck the squareness. Not getting everything well aligned is heartbreaking.

You will notice that you are creating a box that does not open. After the glue has had time to set fully, you need to separate the lid with a table saw. Set your table saw fence to 1.25" from the top lid side of the box. Adjust the depth of the saw blade to 0.6". Using feather boards to hold the piece against the fence, cut the front and back of the box.

Before you cut the sides of the box, you will need to put shims in the slots you just carved and hold the box together with painter's tape. The shims and tape will prevent the wood from moving when you make the final cuts.

In the original version of this box, I had separate pieces for the top and bottom parts of the box. Although this worked adequately, the alignment and squareness were just a bit off. By this as a closed box, you avoid this issue entirely and cut down the construction time.

At this point, you will need to sand the project. Remove any sharp edges, and then go through higher grits of sandpaper until you have a smooth finish. I went up to 400 grit sandpaper in my project. I used a tack cloth after the final layer to remove any fine layers of dust.

To finish the box, I used spray shellac. It is effortless to use and produces a beautiful finishing after about three coats.

Once the box was dry, I used clamps to attach the lid firmly to the base. I carefully drilled pilot holes and used the tiny included screws to attach the hinges. These are delicate pieces, so make sure to measure the locations carefully before you drill.

After the hinges were in place, I attached the latch to the front of the box. Again, do this slowly and carefully, so you don't place anything in the wrong place.

The final step I did for the project was to create the interior lattice for the box. I built the lattice from 0.25" red oak I found at the local big-box store. The height of the pieces is 2.75", which puts them about 0.25" below the lip of the opened box. I generated interconnections using the CNC software. You design your piece and place the slots at the preferred location. The fit was flawless. I did a light sanding on the wood, but I didn't want to finish it. I thought the feel of the unfinished wood might add to the aesthetics of the piece.

I decided to add a self-adhesive felt piece to cover up the plywood bottom of the box. Cut the piece to size and carefully put it into place.

This project was my first attempt at making a small, ornate box. My wife is pleased with the results and is looking forward to showing the box to guests as soon as we have complete immunity. If you don't have a CNC, there is nothing about this design that should deter you. I would suggest using a different kind of joinery to make the frame's construction a bit easier. You could use another type of design for the top. Anything from stains and stencils to hand carving would be attractive. A router table would come in hand for the grooves and floating lid.

If you haven't built a project like this, I encourage you to give it a try!