Wednesday 11 July 2018
Rustic materials are made even more interesting by contrasting design elements. This table has a 559mm wide natural-edge spalted soft-maple plank top. The base is a trestle that uses an interesting joinery technique of overlapping parts. The natural-edge top contrasts with the more contemporary finely finished trestle base. You can easily modify this design to fit the size of slab you may have available.
But I also made a second base, which uses a branch-and-twig style construction more common in rustic work (see technique on page 55).
Making the top
1-2 The first challenge was to plane the board for the top with my planer, which was narrower than the width. This could have been done with hand planes and sanding, but if you have a planer and a jigsaw, there is an easier way that also adds interest to the finished table. I make a meandering end-to-end cut through the plank after sketching it out on the wood.
3 I can now run the two halves through the planer to flatten and make them the same thickness. Another advantage of this cut is that it better allows for seasonal expansion and contraction of the top. The small gap in the middle narrows in wet weather and widens in the dry. After the board is cut in two parts, it is easier to plane both parts down to uniform thickness. Plane the wood down in small increments for the best results.
4 To create a hint of symmetry, I cut angles on one end that roughly reflect the angles of the crotch on the other end. On the crotch end, I left the marks of the saw that cut down the tree and the weathered surface, allowing these surfaces to tell a bit of the wood's story. These decisions are where a woodworker's natural creative judgment comes into play. Each piece of wood is unique, requiring unique decisions on the part of the craftsman.
5. I use a rotary chisel to create a texture on the edges of the stock. It is an easy way to hide the sawmarks. But it also provides an interesting contrast with the more finely finished top surface. I do this on both the cut between the two halves and the edges and ends of the boards. The texture eases the transition between the sawn and natural edges.
6 Sand all the surfaces of the tabletop. Using a random-orbit sander, move through a progression of grits, from 100grit through 320grit. I use Danish oil finish that penetrates into the wood, building up a slight gloss over successive coats. One additional advantage of this approach is that I can give it extra protection with a spray coat of satin polyurethane after the Danish oil is dry â€“ usually 24 hours. I use the polyurethane when I know that the table will be subjected to hard use and requires extra protection, or when the gloss from the Danish oil is uneven.
Make the table trestle
The design of this base comes from the simple concept of the log-cabin corner. By overlapping parts, a rigid structure can be created. Although a similar base could be made using solid, thick materials and mortise-and-tenon joints, this technique makes very strong long-lasting construction easier, using fewer tools. I first saw it used for furniture in Fast Furniture by Armand Sussman. Although I made my base using white oak planed on both sides to uniform dimensions, an even more rustic base can be made by just planing the centre boards on two sides and planing the outer boards only on the inside surfaces, leaving rough weathered wood to present a rustic look.
7 I begin by ripping planed stock on the tablesaw to the dimensions shown in the materials list. Here I used white oak, but any other wood will work as well. This same work can be done with a handheld circular saw and ripping guide. I use a crosscut sled on the tablesaw to cut the parts accurately to length.
8 Join the parts of the centre layer with biscuit joints. This process could be done without this step and the next, but I find that I get more precise results this way. Building up this centre layer with biscuits and glue holding the parts together first, will make it easier to align the parts that are attached to the outside.
9 Glue and clamp each middle layer together, giving special attention to ensure that all the edges line up. The extra C-clamps shown in the photo are intended to ensure alignment. Once dried, trim the angled ends on the assembled trestle core sections.
10 I chamfer the edges of the centre trestle sections with a router, but you can choose your own profile. A roundover would work as well and be easier when it comes to sanding.
Mortising the trestle legs
This is the hardest part of making this table. You need to mark out the position of the mortises accurately, then drill from both sides. This is important to avoid tearout on the underside when the drill exits the wood. Next, some chisel work is required. So, if you are an inexperienced woodworker, please welcome the opportunity to learn a new technique.
11 Mark the beginning and end, or length, of the mortise on the trestle with a pencil. Set a marking gauge so that the pin scribes at the centre of the assembly, whether you scribe from one side or the other. Then pull it toward you between your pencil marks to scribe the centreline for drilling.
12 Use a power drill, brace and bit, or drill press to drill pilot holes for forming the mortise. If using an auger bit, the drill can exert a great deal of force, so clamp the workpiece down to a solid surface to hold it steady. Also, drill in from both sides to avoid tearout where the drill exits the wood. Space the holes to overlap, so that most of the waste wood is removed by the drill.
13 Next, use a wide chisel to remove the remaining stock between the holes, finishing the mortises. Chisel in from one side and then turn the workpiece over to finish the cutting from the other side.
Make the trestle rail
The trestle rail, like the legs, has three layers, glued and nailed together. The longer centre forms the tenon for attaching it to the legs, and the side strips and faces attached to each side provide a firm shoulder that butts up against the legs to hold it in position.
Plane stock for the centre board in the trestle assembly to 19mm thick. It should fit into the mortise perfectly. If not, it can be planed down slightly to fit, or the mortise can be widened with a chisel. Use a 9.5mm quarter-round bit to round the corners about 100-125mm in from the ends. You only need to round the centre of the trestle partway, just beyond the point where it's hidden inside the side strips and faces. Drill the mortises in the trestle centre – these will capture the wedges when assembling the table. Finish the mortises by paring the waste out with a chisel. By paring from both sides, you can avoid tearout.
14 The next stage is to glue and clamp the side strips on the edges of the trestle rail.
15 After those strips have been glued in place, add the face pieces to the rail. You can use a nail gun in place of clamps to hold these parts in place as the glue sets.
Make the wedges
Making wedges is easiest and safest to do by hand. Rout the corners of a piece of wood 19mm thick (or the width of the mortise in the trestle board), 75mm wide, and about 203mm to 254mm long. Use a 9.5mm quarter-round bit. Next, mark a line at a slight angle (2 or 3°) along the length of the board to form the shape of the wedge.
16 Saw out the wedge with a fine-tooth handsaw.
17 Slide the wedge tightly in place and mark it for trimming to length. I cut each end at a slight angle so that it aligns on both sides of the trestle.
Attach the trestle to the top
18 Attaching the base to the two top boards is easily done with wood screws. I used four screws to attach each board. These connect through the upper part of the base and are just a few inches apart. This reduces the impact of expansion and contraction of the top boards, as they can freely expand both toward the centre gap and toward the outside.