A fun lesson in mortise-and-tenon joinery, this coffee table’s versatile design shows off “cool wood” accents while offering a practical storage shelf and foot-traffic-friendly trestles.
Recently I built a coffee table that needed to look good in a rather eclectic setting. Flavors of Arts and Crafts, contemporary and even traditional styles can be found in this table, a piece of furniture that makes its own statement and yet feels at home in many interior settings.
In addition to versatility, the adapted trestle design allows for the functionality of shelf storage, removes the typical four legs that sometimes pose as “knee knockers” and rounds the edges on the base components to provide a more comfortable feel to shoeless feet.
I wanted this table to be sturdy and practical. In contrast with most other pieces I have built, this project calls for thicker stock in many of its components. I believe the trestle design offsets the mass and allows the table to appear lighter and more open. The height is established at 19", a hair taller than most coffee tables, to allow room for a shelf below the top. The shelf is a great place to stash reading materials, remote controls and the like, keeping its handsome wood surface free and clear.
This design will provide good practice for a variety of mortise-and-tenon joinery. In addition to the more traditional enclosed mortise-and-tenon joints, I also added pinned and exposed tenons in the breadboard ends, and even some through tenons on the trestle legs. I highly recommend keeping your cutoffs and scraps handy for test cuts and test-fitting the joinery. I find that “rehearsal” cuts are a great way to assure a good fit before cutting actual components, and can often save you from unpleasant surprises.
Getting started
While not mandatory, this design does offer some places where “really cool wood” can be used as accents, adding interest to the finished piece. If you’re like me, you probably have a few small pieces of fantastic wood stashed away, just waiting for a project that needs only a couple pieces here or there.
On my table, I used some flame cherry in the breadboard ends, and some wonderfully figured bird’s-eye maple in the decorative panels between the trestle legs. Any number of figured woods might lend themselves well to this application, so if you have something special, dig it out and give it a shot.
Before cutting any wood, lay out a series of candidate boards for the tabletop side-by-side. Compare the boards and select those that have similar color and figure for use in the panel. This design has heftier components in the base, so for a cohesive appearance I made the top 7/8" thick. As with all panels, flatten one side of each board on the jointer and then plane to thickness. There is no rule about how many boards to use for the panel, but with the 25" width of the top I chose to use five 5"-wide boards for symmetry.
Since it is important for the breadboard ends to be the exact same thickness as the panel, choose and plane your boards for them at the same time.
Leave your panel stock slightly longer than needed, but rip and joint it to the finished width. Arrange the boards side-by-side and compare them for the flow of the figure from one board to another, then mark each board for its position in order (Fig. 1). You can also strike lines across all the boards approximately where they will be cut to length to indicate their position lengthwise.
Cut the panel stock to its 44" length, saving the offcuts for test cuts when making the tenons later. For gluing up the panel I used simple butt joints with yellow glue. With five boards, I find it easier to glue two boards together by themselves, and the other three together separately. When those two partial panel sets are dry, glue and clamp them together to create the full panel (Fig. 2). I am a believer in allowing the glue squeeze-out to dry and scraping it off later. Once you remove the panel from the clamps, carefully level the surfaces with a belt sander or hand plane.
Breadboard ends
With this design, I chose to use open mortise-and-tenon joinery to attach the breadboard ends to the top panel. The open joinery complements the through-tenon joinery on the trestle leg assembly. The maker and recipient of this table must understand that the tenons on each end of the panel will move as the panel expands and contracts. Therefore the tenons will, at times, be either slightly recessed into the mortise or slightly proud. That is a natural occurrence of that joint.
If that effect is undesirable, then a closed version of the joint can be used without great compromise to the overall design. Keep in mind, however, that the top panel will still shrink and expand, so the breadboard ends will rarely be flush with the sides of the top panel. Again, that’s perfectly normal for construction involving breadboard ends.
Start the breadboard ends by cutting two pieces of your planed stock to 25" x 31/2 ". Select which long side will be joined to the top panel and pass it through the jointer to get a straight edge.
Set up the table saw with a 3/8" dado set, raised so it makes a 1/2 "-deep cut. (That’s only half the final depth required, but a full 1" cut may be too aggressive for safe results.) Set the fence to 1/4", using feather boards to hold the work tightly to the fence, and run each breadboard blank through (Fig. 3).
Turn the blank around and repeat the pass to ensure that the mortise will be centered. Reset the blade to a full 1" depth and repeat the cuts as before.
As an alternative, the mortise dadoes can be cut on a router table. Again, take multiple passes to achieve the full 1" depth.
To cut the tenons on the tabletop I chose to use my table saw with a dado blade, since I have a 52" fence with an extension table which allows me to cut a panel of that size. However, if you don’t have a large enough extension on your saw, the same results can be achieved with a handheld router fitted with a straight bit and a straightedge guide clamped to the panel.
The tenons should be 1" long to match the depth of the mortises previously cut. My dado set can’t cut a full 1", so I adjusted the blades to 5/8 " width and cut the tenons in two passes with the blade set to cut 1/4" deep.
Before making the actual cut in the ends of your tabletop, take some of those scraps you saved and make some test tenons for exact fit. Cut one side of the scrap, then the other and test fit it to the mortise. Adjust your dado blade until you have a good fit, and only then cut the panel. Please note that it’s better to err on the shallow side with the cuts, leaving the tenon snug. You can always shave off a little thickness later if you need to.
Set the fence to cut the shoulders of the tenons first (Fig. 4). Cut both ends, flip the panel over and repeat the cuts. Move the fence to cut the remaining portion of the 1" tenons and repeat the series of cuts. If the tenons are too snug they can be shaved to fit with a rabbeting plane or shoulder plane (Fig. 5).
Once the breadboard end joinery is cut, you’ll need to drill holes for the pegs that secure the ends to the tenons.
Dry-fit the ends onto the panels, tapping them into place with a mallet and securing them tightly with bar clamps. Lay out and mark the centers for each peg. As I used five boards for the top I used five pegs, one centered on each board. The center for each peg should be 1/2 " from the edge of the joint, placing each at the center of the tenon’s length. Use an awl to create a pilot point for a 1/4" drill bit.
With the end still clamped in place — and with a piece of scrap clamped on the underside of the breadboard to avoid tearout — drill all the way through for each peg, keeping the bit perpendicular to the panel. Drill all the peg holes on both ends of the top. Unclamp, and remove the breadboard ends.
To allow for seasonal movement of the top panel, insert the drill bit into each of the four outside holes in the panel tenon and elongate them as in Fig. 6 by working the drill sideways across the grain. (Since no movement occurs in the center, there’s no need to elongate that hole.) For a good, tight-fitting joint, don’t widen the holes in the tenon with the direction of the grain. This will keep the breadboard snug against the shoulder of the panel tenons, but still allow for lateral movement.
Cut 10 1" lengths of 1/4" walnut dowel. These will be the pegs that hold the breadboard in place.
Keeping seasonal movement in mind, glue should be applied only to the very center of the mortise-and-tenon joint and to the pegs so as to not restrict the panel.
Start on one end of the panel and apply glue to a 2"-wide area on both sides of the tenon around the center peg, but nowhere else. Fit the breadboard back in place, making sure the peg holes are aligned, and clamp it into place. Partially tap each peg into a hole. Apply glue to the last 1/4" of each peg and continue to tap them in (Fig. 7), leaving them slightly proud of the surface on both top and bottom. Repeat this process on the opposite end. Once the glue has dried, remove the clamps and trim the pegs flush.
Make a template to help lay out and cut the curves on the breadboard ends. You can use cardboard or even thin plywood, but I’ve found that cheap resin paper works best. It’s a great heavyweight paper that’s easy to cut and has served me well for layout templates.
Draw a straight line 25" long on the paper, and draw the 11/2" ends of the breadboard at each end of the straight line. Draw a centerline 90 degrees from the center of the straight line and mark it at 31/2". To form the curve, take a thin strip of hardwood — a 1/8"-thick strip of scrap works fine — and hold the strip at the center mark, bending it to meet one of the side marks. Flex the strip to create a gentle curve, hold the strip to the marks, and then use a pencil or pen to scribe half of the curve (Fig. 8). This procedure will require an assistant or a simple jig to capture one end of the strip, allowing a free hand for scribing the curve. I just clamped a small block to my workbench and tucked the end of the hardwood strip against it.
Cut the half-curve portion of the template (Fig. 9), fold it over at the center and trace the other side of the curve to ensure a symmetrical arc (Fig. 10), then finish cutting out the template.
Tape the template onto the breadboard ends and trace the curve onto the stock (Fig. 11). Remove the template and use a jigsaw to carefully cut the curves (Fig. 12). Give them a good sanding to smooth them out and remove saw marks.
A solid base
Begin building the base by cutting and dimensioning all of the components, using the drawing on page 39 and the cut list on page 41 as guides. I usually mark the mortises before cutting the curves on the trestle arms and feet, taking advantage of the square stock for layout references. Then, as with the breadboard ends, cut out paper templates for laying out the curves on the trestle feet and arms. Trace the curves onto the stock and cut them on the bandsaw (Fig. 13). Sand the curves smooth, then ease the edges of the rounded sides on the router table with a 1/8" roundover bit.
Take the four vertical trestle supports and cut the 11/2" tenons on a table saw equipped with a dado blade, or on a router table. As with the panel top, these tenons are longer than the dado set or router bit is wide, so you’ll need to take multiple passes. Start with the shoulder cuts first, setting the dado to 1/4" deep. Use your miter gauge to keep the work at 90° to the blade or bit, and make a pass on all four sides, then repeat on the other end. Make the final passes to finish the ends of the tenons (Fig. 14).
A bench-top mortiser can make short work of the necessary mortises in the trestle arms and legs. Lacking one, you can use a Forstner bit in the drill press to remove most of the waste material from the mortise (Fig. 15), then bench chisels to cut the corners and clean up the sides of each mortise (Fig. 16). Take your time, test fitting the tenons as you go.
Cut the tenons in the lower shelf supports using the same process as you did on the trestle end supports. This is also a good time to drill and countersink the screw holes for attaching the lower shelf.
Lay out and mark the through mortises in the centers of the vertical trestle end supports. Again, lacking a mortiser, you can remove most of the waste material on the drill press, backing your work with scrap to control tearout as the bit exits the stock. Square up and clean the sides of the mortises with chisels as before, test-fitting the tenons as you go. Since this is an exposed through tenon, you’ll want a clean fit. Use a 1/8" roundover bit on the router table to ease the lower edges of each support.
Mark and drill the holes for the pegs that help secure the through tenons. Use a trestle support to mark the near side of each peg hole flush with the face of the support (Fig. 17), centering the holes vertically on each tenon. Drill 1/4" holes through the tenons, backing your work to control tearout. Cut four 11/4" pegs from a 1/4" walnut dowel and put them aside.
Cut and bevel the cleats used to secure the top, drilling and countersinking three evenly spaced screw holes in each cleat. With the drill bit, elongate the two outer holes in each cleat to allow for movement of the top panel. Glue the cleats to the top edge of the two arms of the trestle end, and clamp until dry.
This is also a good time to drill and countersink a pair of holes through the shelf supports, locating the holes about 10" from the ends of each support. Because the shelf is only 11" wide, the amount of seasonal movement isn’t critical, so no need to elongate these holes.
Make the shelf panel out of 3/4" cherry stock. The shelf can be made from a single piece of stock, or glued up out of narrower pieces. The figure in the stock you use here is less important, as it is overshadowed by the tabletop. Mark 2" radiuses at the corners and cut with a jigsaw, then smooth the curves with a sander.
The “floating” decorative panels in the middle of each trestle end serve as decoration and interest, and make a good opportunity to use contrasting and nicely figured woods. Since the cherry used for the rest of the table will darken with time, I suggest a lighter wood to add some contrast. I had some nice bird’s-eye maple, but you can substitute whatever you like.
Once you’ve cut your decorative panels, lay out their position on the two vertical trestle supports by sandwiching each panel with its corresponding supports and clamping them together.
Measure and lay out the locations for the pegs that connect the panel to the supports with a square, and strike centerlines for the pegs across both supports and the panel (Fig. 18). Turn the panel, reclamp and mark the centerlines for the other side to ensure precise alignment for the pegs. Drill all the holes 1/2" deep with a 3/8" bit on the drill press. Cut the eight 13/4" pegs from 3/8" walnut dowels and set aside.
Finishing
For most projects, the next process is usually assembly. However, this one lends itself very well to applying the finish before final assembly since there are a lot of nooks and crannies.
The heartwood of cherry darkens and becomes richer in color over time, so I like to allow projects made with it to develop a patina naturally. There is nothing wrong with staining or dyeing cherry, but be aware that the wood will still naturally darken and the combination of natural darkening and added color might eventually make the piece darker than intended.
All parts should be sanded to 220-grit and wiped clean of dust. Apply a coat of Danish oil to all sides of the parts, including the shelf and tabletop. Be sure not to apply finish to the tenons or in the mortises; it could hinder glue adhesion later. The exception is applying finish to the portions of the through tenons on the sides that will be seen.
Allow the oil to dry and wipe all parts clean, then seal the parts with shellac. While I usually don’t stain or color cherry, I do like to use dark garnet shellac. The garnet color of the shellac adds a warm tone that will enhance cherry’s appearance even after it naturally darkens. Seal with two applications of shellac, lightly sanding all areas with 600-grit wet/dry sandpaper when dry. Remove all sanding dust.
Because this table will likely be subjected to food and drink – it is a coffee table, after all – a satin polyurethane varnish is a durable choice of finish. Apply the poly to all surfaces except the pegs and the underside of the shelf and tabletop (Fig. 19).
After the poly dries, sand again with 600-grit paper and clean. Build the finish to a desired uniform result with additional applications.
Once the poly has fully cured, you’re ready for assembly.
Bringing it all together
Assemble the trestle ends first.
Glue the 3/8" pegs into the decorative accent panels, then mount the panel between the vertical trestle supports. Insert the support’s tenons into the mortises of the trestle feet and upper arms. Clamp and allow the assembly to dry (Fig. 20).
Unclamp the end assemblies when dry and attach the two shelf supports, applying glue only to the contact areas of the shelf support tenons. Once the tenons are through, tap the 1/4" walnut pegs partway through the holes. Apply a small bit of glue to each peg just near the hole and continue to tap into place, centered on the through tenons. Wipe off any excess glue. You’ll notice that because the surfaces are already finished, wiping up excess glue is quite easy.
Check that the shelf supports are square to the end assemblies and clamp the base with bar clamps until dry (Fig. 21).
Remove the clamps and attach the top next using #6 x 11/2" screws through the holes drilled earlier in the cleats. With the top in place, attach the lower shelf with #6 x 11/4" screws through the holes in the shelf supports.
As with most projects, feel free to alter the dimensions and materials to suit your needs and tastes. We’ve enjoyed this particular design in our home for many years, as have our guests.
Thomas Skaggs
An architect and planner for the University of Illinois at Champaign, Skaggs is a furniture designer who was featured in the very first issue of Woodcraft Magazine. He developed his woodworking skills while renovating the home he shares with his wife, Donna.
Tools used in this project
Table saw, planer, jointer, clamps, belt sander, random orbit sander, hand plane, dado set, router, jigsaw, drill, drill press, Forstner bit, hammer or mallet, bandsaw, miter gauge, square, chisels.
Materials
Sandpaper in variety of grits to 600
Resin paper
Glue
Danish oil
Garnet shellac
Satin polyurethane varnish
