Glued-up Tabletops

The following is excerpted from Derek Jones’ new book “Cricket Tables.”

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Edge jointing narrow boards to make up a wider panel is the most common way to achieve large components. The technique is a constant theme among woodworkers working with solid timber because it forms the basis of nearly every project both large and small. Though the concept is simple, execution is quite a different matter when faced with a list of the recommended dos and don’ts. Take a deep dive into the subject, and you’ll no doubt conclude that everyone else is an expert in this field, blessed with an unlimited number of boards to choose from that somehow result in the perfect panel. If only that were the case.

In the quest for the ideal panel, the best piece of advice I can offer is to take a few deep breaths first, then consider what role the panel has to play in your project. This is the most important decision you’ll make in the entire process so be clear about what you are aiming for and base everything else around that conclusion. Do not waver. You can start by asking yourself a few questions about the performance qualities of the panel. The conversation should go something like this:

– Does my panel need to be stable across its surface, i.e. not cup or bow?
– Am I concerned about shrinking?
– Am I more concerned about the visual impact of the component or do none of these matter because I just need to be able to work the material with the least amount of effort?

Get the answers to these questions nailed down first, and I promise you’ll be building furniture while everyone else is still making enemies down at the timber yard, pulling planks off the rack in a quest for the perfect board. It’s a fortunate paradox that the conscientious woodworker will struggle a lot less with this. They’ll have resolved all the moral issues about dismissing inferior but perfectly usable boards in favour of a better one and worked out that perfection is the enemy of progress. Now that’s not to say there won’t be some awkward conversations along the way, but a better way of framing the question is to regard it as a non-confrontational negotiation where everyone’s voice is heard and maybe even accommodated.

What is required of a panel to make a top for a cricket table? Historically it would appear that every type of board is up to the job. A single slab of elm, for example, will look stunning if you like random swirly grain, but it will twist and bow in every direction before it’s completely at ease in its surroundings. By all means make a note now if this doesn’t sound appealing – but don’t rule it out completely because I guarantee that a few years down the line it will give great pleasure to somebody. In some instances, dimensional stability is crucial to the success of a product. Wooden handplane makers covet quartersawn blanks for their plane bodies; for case furniture, cabinetmakers will select them for drawer components. Luthiers are notoriously selective in their choice of material for reasons associated with resonance and tone. In fact, every woodworking discipline has a preference. Quartersawn boards are generally easy to spot because their grain pattern is visually dull compared to other boards. On the large face of the best boards the grain will run in evenly spaced lines that are parallel to the long edge. At the end of the boards the grain will run perpendicular to the wide faces for the full width of the board. Boards that display these characteristics are your best chance of achieving dimensional stability, but offer little in the way of visual stimulation. They will, however, garner you some brownie points from the more technical observers in years to come. There is one notable exception to this rule and that is quartersawn oak. The wide faces on these boards can often feature pale translucent flecks known as medullary rays.

Perhaps the boards you are most likely to find in your timber yard are those referred to as plain-sawn boards, sometimes referred to as crown-cut boards. These are the ones that feature a large arrowhead-shaped grain pattern on the wide face of the board running along its length. The grain pattern on the edge of these boards will typically run diagonally from large face to large face. The closer these lines are to being parallel to the wide face the better in terms of strength and workability. The ends of these boards will display anything from a perfect semicircle to a gentle curve grain pattern emanating from the centre (core) of the tree. All of the above details can be applied to the species of wood most commonly used to make cricket tables in the past, and those featured in this book. They are, in no particular order, oak, ash, elm, beech and pine….

Joined Boards
Tops that are made by joining boards together generally result in tops that are thinner than slab tops and require a different technique for fastening the legs. Quartersawn boards, as discussed earlier, offer little resistance to aesthetic compliance or construction. The preamble leading up to a good edge joint between boards is fairly straightforward. There’s more on this subject in Chapter 5. Plain-sawn boards, on the other hand, require some extra thought.

I’ve noticed over the years that one of the trickiest things to get right when demonstrating or teaching something, whether it’s a face-to-face delivery or written explanation, is to pitch it right. Aim too high and you risk going into detail that’s either theoretical or subjective. Too low and your audience loses interest before you can get your core message out. Somewhere in the middle is a sweet spot with carrot and stick in equal measure. The key is to never assume prior knowledge, and it’s with that in mind that I’m going to talk about board selection from the ground up in relation to plain-sawn boards.

If you want to understand how a piece of timber will react to changes in the conditions it’s being worked, used or stored, try this simple exercise. Take a ream of standard copy paper from the printer – the more sheets the merrier. Ask your bench buddy to hold it mid-air with one hand at each end so that it sags down in the middle. Now take a Sharpie or similar felt-tipped marker and draw the shape of your board as viewed from the end directly onto the side of the ream of paper. The sheets of paper roughly represent the annual growth rings of your timber displayed as arcs of light and dark grain. Now let your bench buddy relax slowly to allow the ream of paper to lay flat and note what happens to the sketch of your flat board. That’s right, inside every straight plank there’s a bent one trying to get out.

You can try this with quartersawn boards, too, and even boards that have irregular grain to give you information about how your board wants to react. The results may be extreme and a little exaggerated, but at least now you can see in what direction the faces and edges are likely to go as the board loses moisture. The opposite happens when a board takes on moisture. Now apply this information to the orientation of your boards and note the directional forces that come into play as the edge joints are aligned. Assuming that joint integrity is your primary concern over that of flatness, then orientating your boards in a repeating pattern of arcs up and then down will give you a joint with the least stress. In fact the stresses are working in your favour. If you’re one of those people who see data and convert it into probability this is your algorithm of choice. But there’s a downside – you’ll never have a truly flat top.

Earlier when I explained how to identify plain-sawn boards I mentioned that the grain on the edge of the boards runs diagonally from face to face. In finishing terms this could be problematic as planing toward grain that is poking up is likely to leave behind a rough surface. The fix should be quite simple, just turn the panel through 180° or plane in the opposite direction. But what if the adjacent board or boards now have grain exiting the face up toward you? Again the fix is quite simple but not always effective – first try skewing your plane as you pass over the offending area. If that doesn’t work consider localised planing in the safe direction with a shorter plane; if that fails, reach for the card scraper. When this happens you’ll immediately start to question your decision-making process and wonder if it could have been avoided. The answer is almost certainly not.

The final conundrum in selecting boards for a panel is the way they look. This is often where people get sidetracked from what is important and it’s completely understandable. If wood were uniform in grain structure, density and direction, you could align your boards and therefore avoid difficulties in processing by following a strict set of rules. The reality is that there aren’t any, apart from the one where you actually look each piece of timber in the eye and read the grain. There’s really no substitute. In the likely event that you will end up with boards that can only be planed in one direction without tearing out you’re going to need a repertoire of reliable techniques to deal with them. Some of these include adjustments to your plane setup like creating a back-bevel on the back of the blade to increase the working angle (pitch) of the blade. Increased angles behave more like a scraper and therefore are less likely to tear up the surface of the board. They also require more effort to produce a cut, which can be counter-productive in some cases. The most common school of thought related to this is to set up the plane with the finest mouth aperture possible, although I know of one planemaker who eschews the idea.

It’s fairly obvious by now that I’ve never found logic to be a particularly helpful resource when it comes to selecting boards for a panel. In theory it’s feasible to join boards of the same thickness together edge to edge without creating lips but it’s more common not to – even those prepared on a machine.

Typically when the clamps are removed you’ll have some leveling off to flatten and smooth the panel. If you do carry out your timber prep with machines, you’ll need to do something to remove the compression marks from the cutting edge. Although the board will appear flat, straight and square, the surface is a series of ripples that alter in size depending on the depth of cut with each pass and the speed at which the board was fed through the machine. If not dealt with, the crests of these ripples can show when you add a finish to your work. Taking to the surface with a coarse abrasive is one way of removing them, but as the ripples are caused by compression and not just a cutting action, you’ll need to do a lot of sanding. With the exception of some hard waxes, all finishes have a degree of moisture in them, whether it’s oil, alcohol, water or any other solvent. As soon as it comes into contact with the compressed area at the bottom of the ripple, the fibres begin to swell, causing the peaks to rise up again. If you have just laid down your first coat of finish this can be a real pain. Sanding the surface now will clean the peaks of any finish, leaving stripes of bare wood. If sanding is your only option, a good way to avoid this happening is to wet the surface with a slight mist of water or a damp cloth to raise the grain and allow it to dry. (If time is limited, a 50/50 blend of water and alcohol dries slightly quicker.) The effect is to neutralise the compressed areas and make the surface stable. When it’s dry you can sand to your heart’s content knowing that when you apply your first coat of finish it could possibly be the last. A good alternative to this is to treat every surface to a light pass with a smoothing plane.

The amount of work required to improve the surface of your panel after gluing up varies from project to project and to a large extent success depends on the tools you have at your disposal. But first of all let’s not measure success in terms of quality; instead try using efficiency as your benchmark. For example, if a lot of material needs to be removed then you’ll want to be using a plane with a cambered blade. You’ll also want to be traversing the panel diagonally from corner to corner to save time and minimize the chances of tear-out. You’ll want to follow up with a shorter plane that also has a slightly cambered blade to dress the final surface. And you’ll want to have a well-tuned card scraper on standby for when a plane just isn’t cutting it.

None of the above requires specialist equipment. You probably have a number of these tools in your armoury already: a jack plane, a smoothing plane and perhaps even a regular block plane. It’s worth mentioning that all and none are indispensable when it comes to wasting away unwanted material. The only advantage in owning all three is that you might be quicker – that’s it.

To put this in perspective and to stop you fretting over the way you lay out boards consider this comparison: If two eight-studded LEGO bricks can be assembled in 24 different ways, how many ways are there to join three boards of timber to make a perfect panel? Answer: Who cares? It’s a rhetorical question because my point is that the panel you end up with is the perfect panel. So here’s the deal, work with what you have to get you building quickly, and spend your time developing strategies for coping with some of the less desirable features. Sorry, I said spend your time; what I should have said was invest.

If there’s an underlying theme to this book it’s to encourage you to recognise and embrace naivety, and for good reason. At no other time in your quest for knowledge and proficiency at designing and building furniture were you more exited and driven than when you first got the bug for it. Return to that headspace as often as you can because if you’re not careful you’ll acquire so much knowledge that it makes progress impossible for a while. My advice here is not to confuse theoretical knowledge with real-world experience. Make mistakes, learn how to correct them or, better still, learn how to spot them before they happen.