Build an X-base dining table
A dining table is the centerpiece for many great family moments. This classic, refined design is a minimalistic approach to what can often be a complex project.
With its fairly simple lines, and little visual and physical clutter underneath to allow for plenty of legroom, this table has a simple, refined overall look. The black cherry’s rich colour and grain are two of the table’s strongest features.
When dealing with angles it’s easier to have a full-size drawing to work toward. Here, Brown marks the half lap locations on one of the cross pieces and clearly marks the waste portion of the joint.
Remove the Waste
A dado blade removes wood quickly, but a standard width blade will also get the job done. Just be sure not to remove too much material or the resulting half lap joint will have gaps.
Dominos to the Rescue
There are many ways to cut this joint, but a Domino machine is one of the quickest. The remaining waste on the upper end of the cross pieces will be removed with a hand saw and chisel.
Unique Floating Tenons
Though typically straight, a floating tenon can be made to almost any shape to increase the surface area for gluing. The depths of the mortises need to be cut carefully so they’re not seen on the visible side of the joint.
Once the floating tenons are dry fit, mark them as well as the joint in general with a letter or number so you can be sure to assemble them the same way.
Bring it Together
Bring the half lap joint together first, then position the top rail in place and insert the floating tenons. A few clamps will tighten up the joints and ensure a bomb-proof base assembly.
Trim the Top
Take a small amount of material off in order to even out the upper edge of the base. A track saw makes the task easy, but either a router or circular saw, and a straightedge to guide it, are other options.
After laying out the joint and making a few kerfs with a hand saw followed by a few drilled holes, it’s easy to remove most of the waste for the notch that will accept the top rail with a chisel and mallet.
To define one side of the notch Brown used a shop-made plywood square to guide his router. It was rotated in order to create the other side of the notch. After the edges were created, Brown removed the middle area by moving the router freehand.
Although it will rarely be seen, Brown shaped the end of the brace extension rails and added texture to it with a rotary tool.
Brown added two Domino tenons to secure the lower end of the angled brace to the cross piece assembly. By clamping a straightedge to the cross piece assembly and marking the joint locations on it, the mortises were created quickly and accurately. The next step involved laying out the joint on the end of the angled braces and using the Domino cutter to machine those two mortises.
With the angled brace cut to size and the joinery fixing it to the cross piece assembly, the brace extension rail can be positioned in place and cut to length.
Mark the Miter
With the angled brace in place, the corner of a carpenter’s square was positioned at the lower edge of the notch in the base assembly. A line could then be added to the upper end of the angled brace and mitered to size.
Chamfer the Edges
A router will chamfer the edges of the base before final assembly.
Take Care with the Corners
A router bit can only get so close to each of the corners, so a chisel is needed to remove the final bits of waste. Take time here to keep the chamfer lines as straight as possible, as mistakes will likely be easy to spot.
The brace extension rail gets screwed in place at two locations, but the lower end of the angled brace needs to be clamped to the cross piece assembly. In order to do this, an angled caul needs to be clamped to the edge of the angled brace so clamping pressure can be applied perpendicular to the joint.
Cutting a couple of kerfs in a piece of particleboard, followed by adding in two stop blocks to square up either end, makes a quick router guide to cut the shallow mortises for the inserts. The template guide attached to the base of the router follows the opening in the particleboard.
A Nice Fit
The solid inserts can be ripped to width and their four corners rounded so they fit nicely in the opening.
A Systematic Approach
First, Brown dressed the rough lumber flat and to rough thickness. He then glued up boards to make 10" wide panels and dressed them to final thickness. Here he is gluing a third 10" wide panel to the 20" wide section he initially glued up.
Don’t Wait Too Long
Leaving glue squeeze-out to only partially dry before scraping it off is a good approach. It comes off easier and cleaner when it hasn’t fully cured. Waiting a couple of hours is a good timeline.
Flatten the Top
Although he takes care to align the faces of the boards during glue-up as best as he can, Brown starts the levelling process with a hand plane, working across the grain. A belt sander with a 60-grit belt is next, followed by successively finer grits.
Applying a Finish
There are many great options for finishing a tabletop, but Brown opted for a mixture of equal parts oil-based polyurethane, tung oil and boiled linseed oil. It provides a great mix of protection and grain enhancement, while it’s also easy to apply.
Turn it Over
Brown turns the table top upside down to secure the X-bases to the top.
X marks the spot (to start)
I drew a full-size layout on a large piece of paper so I could be sure of the angles and dimensions. The base sections each had to be wide enough to give the width of the table stability.
I began by milling the material for the leg sections to final thickness, then ripping the parts to final width. I left the main cross pieces long at this point, as I was just going to trim them to length after they were assembled.
Taking the angles from my drawing, I adjusted my miter gauge and installed a dado set in my table saw. After a few adjustments to dial in the half lap joint connecting the two cross pieces, I removed the waste from each joint. I was able to remove this material from all the cross pieces with the same miter gauge setup. I marked lines on the workpieces, and cut directly to those lines, checking frequently against the mating piece as I got close. To ensure gaps weren’t created after the fact, I sanded the sides of the cross pieces before ensuring a perfect fit.
With the half lap joints dry assembled there was no movement between the pieces. I clamped them to a work surface with their upper ends overhanging the surface, then used a track saw to trim them to final length. I still left the bottom ends of the legs long at this point. I was now ready to fit the horizontal braces and cut the joinery to secure them in place.
Top rails and open-ended mortises
The first thing to do is to cut these two rails to size and miter their ends to fit perfectly against the top sides of the cross pieces. Ensure the upper edges of the top rails are flush with the ends of the cross pieces. With no gaps between the parts, it’s time to create the mortises to accept the floating tenons.
There are several options for creating the mortises. A router, equipped with an edge guide and straight bit, could be used. A horizontal mortising machine is another option. Even a table saw and dado blade could be used, though the parts would have to be carefully secured during the cuts. I have a Festool Domino XL so I opted for that route. It created aligned mortises in all the parts with relative ease. Multiple cuts needed to be made to create the wide mortises, but that was an easy operation with the Domino.
The tricky thing about the joints that secure the top rails to the cross pieces is that because the cross pieces go together with a half lap joint, there’s no option for a standard closed mortise and tenon joint between the cross pieces and the top rails. You just won’t be able to assemble it. This is why I used mortises that were open at the top of each base, sub-assembly.
I lined the mating parts up, marked where the mortises needed to be positioned, then adjusted my Domino to make the plunge cuts. I ensured the mortises stayed about 1/4″ away from the visible portion of the joint. When machining the mortises in the upper ends of the cross pieces I could only get the Domino cutter so close to the end of the workpiece without having it tilt during the operation. Instead of risking a loose joint I used the Domino as close to the end as I thought was safe, then removed the remaining waste with a flush cut hand saw and chisel before using a chisel to ensure the faces of the mortises were smooth and even.
With the mortises complete I set my sights on the floating tenons, which were uniquely shaped to fit into each mortise. I dressed some solid cherry to the thickness of the mortise, then a bit of trial and error left me with a floating tenon to secure the joint. Although the thickness of these floating tenons needs to be accurately considered, the width and length don’t need to fit perfectly to form a strong joint. Their strength comes from both of their faces, not their edges.
Each one of these joints, as well as the floating tenons, have been fine-tuned to mate with another specific part. Ensure you mark each joint so there are no problems during assembly. I added a letter to each mating part of the joint, but there are many other solutions to this challenge.
To finish off the top rails add two counter-bored screw holes to their undersides. Once assembled, the cross pieces will get in the way of being able to drill these holes. I used #12 screws to attach the top to the base sections.
Base assembly #1
Sand the edges of the parts, as you won’t be able to easily gain access to them after assembly. Be sure you don’t sand the edges of the half lap joint or gaps will be revealed.
With clamps and parts organized, apply glue to both faces of the half lap joints and bring the two cross pieces together with clamps. You could leave this joint to dry, then add the horizontal rail later, but if you go this route ensure the horizontal braces fit perfectly now. If the two cross pieces are glued together at even a fraction of a degree off, the top rails will not fit properly. I opted to continue with gluing the assembly, and added glue to the mortises and floating tenons, then brought the top rails into position and used light hammer taps to persuade the floating tenons into position. While doing this I ensured the top rails remained in their proper position, relative to the cross pieces, for a visually tight joint. When dry, I used my track saw to flush the upper edge of the sub-assembly, leaving the lower ends of the cross pieces long.
Create another triangle
As we know, the triangle is a strong shape, as it naturally resists racking. Although the two base sections would support a small vehicle, they would would offer little resistance to a racking force if someone leaned against the end of the table. My client wanted to keep the underside of the table as visually and physically clean as possible, so I opted for a simple angled brace attached to each base assembly.
To do this I needed to add two more parts to each base assembly. An angled brace would provide the racking protection, and a brace extension rail would keep the end of the angled brace in place for decades to come.
After marking out a notch in the top of the base assemblies (to accept the brace extension rail) I used a hand saw to make kerfs and allow me to quickly remove much of the waste. A router equipped with a straight bit was then used to machine the sides of the notch square and create a flat bottom so the brace extension rail could be glued directly to that surface. I used a simple shop-made plywood square to guide my router to produce the two sides of the notches.
I then machined the two brace extension rails to the exact size needed to fit into these notches. Although it didn’t need it, I overhung the upper rail on the outer edge of each base assembly by 2″, cut a visually pleasing curve onto their ends, then added texture to the end grain. This was strictly for aesthetics. At this point the brace extension rails were still oversized in length, even though one of their ends was complete.
The angled braces were then dressed to thickness and width, and a 45° miter was added to the ends that would be joined to the center of the X-base assemblies. A few Domino tenons were added to these joints to hold them in place. With Dominos inserted in the joint, and the miter on the angle bracket fitting snugly against the inside surface of the X-base assembly, I used a carpenter’s square to determine where to cut the other miter on each of the cross braces so they would align properly with the brace extension rails. With the cross braces cut to size and dry fitted I could determine the length of the brace extension rails, cut them to length, add the curve and texture to their other ends and predrill a few screw holes through the brace extension rails, down into the angled brace and the X-base top rails. I also drilled screw clearance holes through the brace extension rails so screws could be driven into the underside of the table.
Prepare for final assembly
I used my table saw to trim the bottom ends of the legs to length. This could also be accomplished with a track saw, circular saw and guide, or router and guide. I also chamfered all the corners of the base with a trim router, leaving a flat surface about 3/16″ wide. I finished the corners with a chisel, taking time to ensure an even look.
Next, I sanded all of the parts, as these surfaces would be hard or impossible to access once the base sections were assembled.
Base assembly #2
The final two parts of each base assembly were next to be secured into place. Thankfully, neither of the base assemblies are really that onerous. I started with gluing the Domino joints to fasten the angled brace to the cross piece assembly, then added the brace extension rails with some glue and screws. Clamps brought everything together nicely. A 45° clamping caul temporarily clamped to the angled brace provided me with a surface for proper perpendicular clamping pressure.
Finishing the base sections
Although it was strictly for aesthetics, I wanted to add black cherry inserts on the upper edges of the base to hide any slight visual imperfections that resulted from gluing the loose tenons in place. You can skip this step if you’d like.
I first cut a template to act as a guide for a router equipped with template guides. With a straight bit in my router and the template guides in place, I routed two grooves into the upper edge of both base sections. After a bit of work cutting and fitting the solid inserts, I was ready to glue them in place. When dry, I used a plane to level the surface.
Making a 38″ wide solid wood tabletop is easy if you have a 38″ wide planer. If you’re like me, and don’t have that luxury, you’ll need to glue up the top in stages by preparing narrower sections, then gluing them together to obtain the width you need.
I paid special attention to grain and colour when planning where the boards would go. I also alternated end grain growth ring patterns to minimize overall cupping of the finished top.
I have a 12″ wide planer, so I dressed and glued lumber to form sections no more than 12″ wide. When dry I was able to dress them to final thickness, true their edges for edge gluing and laminate these panels together. My approach included gluing two boards about 5″ wide together, then gluing four of these sections together.
I jointed the rough lumber, dressed to within about 1/8″ of the final thickness of the tabletop, ensured their edges were straight and glued them together. At this stage a perfectly aligned joint isn’t mandatory, but it sure does make the process easier. The more evenly the mating boards meet, the better chance you have of success. I was able to manually align the two boards during glue-up, but adding a few dowels, biscuits, splines or Domino tenons along the length of the board will assist you during glue-up.
When the four laminations were dry, I planed them down to final thickness and straightened their edges. I glued the center two sections together, paying extra attention to keep the mating edges aligned. Cauls will help keep the dressed edges undamaged, as clamps can exert enough pressure to cause damage. I like to leave the panel to dry for just an hour or two before removing the clamps and scraping off the partially dried glue. Leaving glue squeeze-out to dry overnight makes it hard to remove cleanly.
Next, I tested the joint for the third panel, and made any necessary adjustments to ensure an even joint. Some glue on both edges of the joint and clamps meant the joint closed nicely. Once all four panels were assembled, I cut the top to size using a track saw. I then used a hand plane to remove any high spots, followed by a belt sander to leave a smooth surface.
I added a small chamfer on the top edge of the tabletop, and a low angle chamfer on the underside. There are many options for creating a pleasing edge on a tabletop, or the edge could also be left square.
Attach the base
The two screw holes on each X-base top rail would house a screw that would attach the tabletop, but I wanted a bit more strength just in case. I cut a Domino mortise into the inside face of either end of both base assemblies. I made sure these mortises were in the X-base top rails of the base, rather than the top end of the leg, as the resulting short grain in the leg would have been too weak. I then made four cleats that would help fix the tabletop to each base section.
With the tabletop upside down, I positioned the base 15″ in from either end of the tabletop and marked the screw locations for the #12 pan head screws. I was careful not to drill through the tabletop while boring the pilot holes. I then drilled pilot holes for the four cleats and screwed them in place.
To protect against rocking I installed a T-nut and leveller foot in the bottom of each of the four legs.
Finish it off
With the base sections removed from the tabletop, I made sure the entire piece was sanded and prepped for a finish. This included marking the base sections, four cleats and underside of the tabletop so I could put everything back in the same pilot holes.
When choosing a finish, weigh the pros and cons of each finish and put them up against the sort of usage the piece will get and the look you want for it. My clients didn’t want a heavy film finish, but they did want a decent amount of protection from spills and wear. They also wanted to be able to still feel the grain when they ran their hand over the wood.
With this in mind, I opted for an oil / varnish mixture. Equal parts oil-based polyurethane, tung oil and boiled linseed oil were mixed and applied with a rag onto all surfaces of the table. After drying for almost two days, I gave the piece a light sand and applied another coat, and another one two days later. After each liberal application of finish, I used a clean rag to wipe all the excess off the wood’s surface, leaving a light, yet protective, layer of finish. This is an easy finish to apply, and good results are almost guaranteed. Just make sure you test it on a piece of scrap wood of the same species before you commit to the entire table, as the look will be different for each species.
After a few days I used #0000 steel wool and wax to smooth the finish. I was happy with the smooth feel as well as the look.