10 Tips for Better Table TopsComments (0)
This article is from Issue 85 of Woodcraft Magazine.
They all add up to a stunning surface.
What’s it take to make a table top? You just edge-glue a few boards together, sand ‘em, and there you go, right? Not so fast. Not if you want something that looks great and represents quality workmanship. After all, a table’s top is its most prominent feature. Sure, it’s basically just a panel, but you can screw it up any number of ways by mismatching boards, milling them incorrectly, or improperly joining them, among other errors. If you want to create table tops that dress up rooms in style, and that show people you know your stuff when it comes to woodworking, check out these 10 time-tested techniques.
- Jointer Fundamentals
- Composing with Grain
1 Start with good material
A good table top starts with good material. If you can, buy boards graded FAS (firsts and seconds). An FAS-graded board must be at least 6" wide, 8' long, and 83.33% free of knots and defects (depending on the species). Unfortunately, many small mills don’t sort by grade, in which case you’ll just have to do the best assessment you can on your own.
Your stock should be close to flat in the rough. Crook, minor bowing, and cupping can all be dressed out, but seriously bowed or twisted boards are almost always a bad choice because they tend to suffer from indomitable internal stresses. Also, dressing out the warp often leaves insufficient thickness.
For the 15-1/2"-wide table top at the bottom of page 32, I needed a board at least 8" wide and twice as long as the top. That way, I could use a single piece for the whole panel, which helps in getting a good grain and color match right at the start.
It’s not all about workability, though. Also look for a board with the potential to be a beautiful table top. Before cutting the board down, scrutinize its edges, considering where to create the seam. For a natural transition, arrange to join straight-grain to straight-grain edges if possible, and try to avoid abutting edges with grain runout, which can create a visual clash at the seam.
Stare it down.
Sight down a candidate board to check for crook and bow. This crook can be ripped away, and there’s very little bow, so it’s in promising shape.
No propellers. A twisted board presents milling problems, and should generally be avoided for table tops. Twist is easily detected by sighting across the tops of winding sticks: a pair of straight sticks of contrasting color placed at the ends of a board.
2 Flitch it if you can
Getting a good grain and color match is much easier if you’re working with a flitch, which is a series of sequentially sawn boards from the same tree.
A flitch can be costly, but it’s well worth the bookmatching opportunities that can create high drama in a glued-up panel. With the walnut flitch shown here, I’m careful to locate my edges so my book match lines up on all of the boards that will comprise the tabletop. Picking a couple of identifying marks like small knots or streaks helps me keep the boards aligned. In the case of these pieces, I measured in from the waney edge.
A matched set. There’s no better way to ensure grain and color consistency than to use only boards from the same tree. These walnut slabs will be judiciously milled and edge-joined to create a simple, but singular, rectangular table top.
3 Switch, flip, and slip to make a match from a random batch
When composing a table top from random stock, enjoy the puzzle! Take advantage of your myriad potential matches by trying every possible combination of boards in every possible orientation. Try to work with the flow of the grain. With flatsawn boards, take advantage of the straight grain typically found on either edge to make a panel with blended seams. The cathedral patterns in the centers of such boards can be artfully arranged, even though such a multi-board constitution will never mimic the grain of a single plank.
If you’re bookmatching a tabletop, a seam in the center makes sense. However, I’m often trying to make up one unified panel without bringing attention to the seams. In that case, using an odd number of boards and keeping the seams off-center will help to randomize the look, leading to a more visually natural composition.
Some woodworkers claim that alternating the heart face and sap face on adjacent boards will “equalize” a panel, ensuring a flatter surface, but I’ve found this to be a myth. Instead, compose the visually best surface, and rely on the panel’s attachment to the table base to keep it flat. Use denatured alcohol as shown to bring out the natural color tones.
In the near photo at right, I arranged the seams to incorporate the sapwood as a design element. In order to achieve this effect successfully, it’s important to use the sapwood from both mating edges to form a natural transition. Otherwise, the colliding heartwood and sapwood would create a hard, straight, visually ruinous glue line.
Once you have a pleasing arrangement, be sure to view it from all sides and angles. Depending on the way the grain is laying, it can reflect light differently, especially with figured material. I’ve been surprised on multiple occasions when the top looked perfect when viewed from one end, but completely wrong from the other.
So just do your best to make the most pleasing arrangement possible. And don’t fret if you don’t get it “perfect.” Keep in mind that wood is a natural material and will only bend to your will so much.
Alcohol enhanced. When working with random boards, do your best to integrate color and grain into one solid composition. Wipe and/or spray denatured alcohol onto the surface to pronounce both grain and color in order to get the best possible match. At left, the lighter sapwood meets at the seams, drawing attention to them, but also providing visual interest. At right, the opposite faces of the same boards join to create a cohesive heartwood composition.
4 Locate rips to minimize grain disturbance
You’ll often need to rip a board down to minimize cupping or just to suit your jointer’s capacity. But before ripping, consider where the kerf is going to fall, and the 1/8" or so of wood that will be lost to it. After the rip, and after jointing both edges, you may lose close to 1/4" of wood to the cuts. If you’ve sliced through the slope of cathedral grain, the interruption is likely to be obvious when the edges are rejoined. It’s best to choose a path through straight grain, where the joint usually comes back together without a trace of a glue line. If your straight grain doesn’t fall in the right place, try bisecting the peaks of the cathedral pattern, which will tend to rejoin nicely.
When rejoining ripped sections, don’t be afraid to shift the parts to achieve the best match. This is particularly a good approach when trying to reestablish cathedral grain flow. It helps to leave yourself as much extra length as possible to make this work.
Also, try to use natural variations in color to create an artful arrangement. Notice the two dark streaks flanking the center seam in the photo at far right. This creates visual interest that also helps draw attention away from the joint.
Don’t interrupt. This panel is constructed from one 8'-long board that was crosscut in half, aiding color- and grain-matching. Each half was then ripped to alleviate cupping. Board #1 was ripped through a straight-grained section, while board #2 was ripped through the tips of the grain cathedrals. At the center of the panel, the two boards meet with a straight-grain-to-straight-grain joint, which makes the seam nearly undetectable.
5 Lay out to avoid tearout
Make sure to keep track of your individual boards’ grain direction throughout the planing process and afterward. If you don’t, you risk accidentally edge-joining them together with opposing grain directions, which invites tear-out when planing the final, composite panel.
I mark the feed direction on every board as it exits the planer. If I notice tear out, I’ll reverse direction on the next pass. If the tearout is reduced, I mark the leading end of the exiting board with “GD” for “good.” This label means “Only plane this board in this direction, or you’ll be sorry.” For example, the crotch grain on the board next to the planer in the photo below looks beautiful as is, but if fed in the opposite direction it would be chewed up beyond repair. The most beautiful boards will often struggle in both directions. The notations made at the planer help me to work with the lesser of two evils and minimize clean-up after the glue up.
Marked for travel. Chalking the leading end of a properly oriented board as it exits the planer ensures that you won’t accidentally feed it the wrong way on the next pass, inviting tearout. You’ll need to re-mark after every pass, so keep the chalk handy as you work.
6 Use a jointer!
Nothing beats a jointed edge for making perfect seams. In my experience, even table saw blades that purportedly create a “glue line rip” don’t really create the kind of neat seam I’m interested in. Joint all mating edges, then do a dry clamp to ensure absolute closure. I like to test the joint using a light-duty “F-style” clamp. If it closes the joint perfectly, I know that pipe clamps will have no problem. Be picky at this stage, and make sure each joint closes perfectly. To help detect the offending edge in a gap, slide one board past the other. If the gap moves with the board, rejoint that edge. If the gap stays in place, rejoint the opposite board.
Feed with care. A successfully jointed edge depends on proper feed technique, especially with longer boards. Make sure to press the face of the board firmly against the jointer fence, and maintain leading end contact with the outfeed table. If the board is short enough, begin with your hand on the trailing end so that you can feed in one uninterrupted stroke.
7 Biscuit long boards
For table tops under 30" long, a simple edge joint is easy to assemble and plenty strong. For longer table tops, I use biscuits as alignment aids to bring adjacent board faces flush. They won’t create a dead-level seam, but they’ll get you pretty close. I start my biscuit layout 4" in from the end to prevent exposing a biscuit when crosscutting the top to finished length. Lay out and cut your biscuits 8-12" apart.
Don’t get sloppy with the slotting, as an angled biscuit may actually force your boards out of alignment. I keep my hand planted firmly down on the joiner’s fence, with the edge of the board overhanging my bench to ensure unimpeded contact with the tool.
Alignment aid. Biscuits help align boards during the glue-up.
When joining the boards, I typically apply glue to only one edge of each joint and to all of the slots, but not the biscuits themselves.
8 Stagger your clamps and clean up the panel’s show face
Pipe clamps offer plenty of power to close an edge joint, while helping to keep the table top flat under pressure. I place the clamps over and under, making sure that the pipes contact both faces of the panel in order to keep it flat. Look for a nice, even bead of squeeze-out along the entire length of each joint.
I use strips of wax paper to prevent black iron stains on the “show” face of the top. I use the bandsaw to cut these little 2"-wide rolls from a standard roll of supermarket wax paper.
Careful clamping and clean-up. Placing half of the clamps on top of the panel assembly equalizes the tendency of the panel to cup under pressure. On the “show” side of the panel, I scoop up the wet excess glue with a putty knife, then remove the upper clamps one at a time to clean up each unimpeded section in turn with clean water. Finally, I protect against black stain by placing a strip of wax paper under each reapplied clamp.
9 Plane in parts
Make things easier on yourself by working to the capacity of your planer. For example, to make a 44"-wide dining table top, I’ll begin by gluing up two separate 22"-wide panels from boards that I planed slightly oversized in thickness. Then, after planing both assembled panels to almost-finished thickness on our 24" planer, I have only have one seam to deal with in my final glue-up. You can apply the same idea to smaller planers. Gluing up separate parts first, rather than gluing up the entire panel at once, might seem like an extra step, but you’ll thank yourself when it comes to leveling the finished surface.
10 Plane and scrape before sanding
Sanding isn’t the best option for leveling seams. A belt sander works in theory, but the reality is usually fraught with divots and tracks. And a random-orbit sander will ride up on the high spots, producing an uneven surface. It’s best to attack the seams with hand planes and cabinet scrapers, which will create a much flatter surface. Start planing at a diagonal with a jack plane, using a straightedge to gauge your progress. Then plane diagonally again, but at 90 degrees to your original direction. When your straightedge indicates a relatively flat surface overall, plane parallel to the grain. Then switch to a smoothing plane and scraper to clean up the previous plane track marks. Don’t worry about creating a glass-smooth surface at this point, just get it to the point where a random-orbit sander can take over.
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