Oak Arts and Crafts Table
Thursday 06 November 2008
Mark Ripley makes a oak dining table in the Arts & Crafts style
This English oak (Quercus sp) dining table was commissioned for a large riverside cottage on the Thames. The dining room does full justice to the piece with its high timber framed ceiling and generous proportions. The client required an extension, from 2100 to 3000mm (approx 83 to 118in). This involved adding two leaves and was easy to accommodate from an engineering point of view. The top is drawn out to cantilever over the ends of the fixed frame. The 'Hayrake' stretcher arrangement is associated with the Arts & Crafts movement and this, together with heavy sections, pegged mortice and tenon joints, and chamfers, gives the table a strong, uncompromising feel. Proportion is just as important in this type of work, as in more delicate furniture, and I spent a lot of time resolving the design. An 1/8 scale model was made and later oversized components were gradually worked down until they felt just right.
Timber preparationThe oak was bought from Alec Golesworthy at Timberpride, near Cirencester. My main concern was finding clean, sound 100mm (4in) stock for the legs and these came from one of a massive stack of boards that had been air drying for several years. I prefer air dried stock for anything over 63mm (2 1/2in). Kiln drying often causes 'honey combing', which is not visible until the board is opened up. This is where the fibres pull apart inside the timber if it dries out too fast leaving an effect similar to cutting down through a honeycomb. If present it can render a board more or less useless.
The board I'd selected registered a consistent 9 to 10% mc (moisture content) throughout its thickness, when sawn through, which is fine. The surface of the board had 'catspaws' on it. These are clusters of very small knots which, in moderation, I quite like. As this is subjective, I did check the client agreed with me before committing myself. She didn't want a solid oak table that looked like veneered MDF. I feel just the same about solid wood, so I could see we were going to get on.
The top was ex-stock, 50mm (2in), some of it a bit uneven but it planed down to a clean 38mm (1 1/2in). As the top alone weighs about 100kg (220lb) I was pleased it was not thicker. For one thing it looks right and, secondly, the leaves themselves are quite heavy and would be awkward for one person to fit if they were much thicker. The top boards were quarter sawn and 9% mc, though kiln dried. Hayrake and top frames were also ex-stock, 50mm (2in), though I ended up using some 25mm (1in) already in stock for the long side rails. This matched perfectly and allowed greater freedom in selecting for the top. As the side rails are braced by the runner guide assembly, nothing was lost structurally and the project still came nicely within budget.
Timber selectionQuarter sawn stock is advisable for extending table tops as the main tops and leaves have relatively little or no supporting framework to keep them flat. In order to ease timber selection, the grain usually runs across rather than along the top on extending tables. Even if the wood was available to create a very large top, with the grain running long ways, the grain would only follow through when the table was fully extended with the leaves in the right order.
Timber selection is obviously important to the overall appearance of a table, but balance rather than blandness is the aim. Production line, solid wood furniture looks uniform because all the products need to match each other, and the samples in the catalogue. People also need to be able to buy pieces from the same range at different times. As makers of one-off furniture we can be more creative with timber selection and finishes.
ConstructionThe leaves needed to be made of boards of equal width, namely two times 225mm (approx 9in). The main tops are made up of 225mm wide boards as well, with the two outer panels being graduated down to form the required overall length. The tops are butt jointed and fitted with biscuits. Both faces are planed flat with a jointer plane and the edges trued up but left slightly oversize for final calibration after fitting to the frame.
The frame - legs and top rails - are marked out for haunched mortice and tenon joints. The legs fitted comfortably under my morticer for a 12mm (1/2in) mortice. These joints are too deep to cut with a router, and biscuits are certainly not strong enough in this context. If a morticer is not available, the bulk of the mortice waste can be removed with a drill and the sides and ends cleaned up by hand.
Drill 8mm (5/16in) holes for the pegs in the legs and clean up any breakout inside the mortice. I use my Startrite 352 bandsaw set with a standard 20mm (2 5/32in) skip-tooth blade to cut tenon cheeks and the bench saw aided by the sliding carriage to cut the shoulders. This is efficient and accurate. Whatever equipment you have it's useful to devise a system for frequently repeated jobs - such as mortice and tenons - so time is not wasted reinventing the wheel for each project. It's also interesting to see how versatile two or three simple machines - bandsaw, jointer, planer and portable router - can be when used in conjunction, often curtailing the need for more sophisticated and expensive equipment. This is particularly relevant in one-person, one-off workshops where profit margins are small and overheads need to be minimalised.
Construction - twoClamp up the frame dry and, having checked all is square, push the 8mm (5/16in) drill bit in to mark the position of the holes in the mortices. Label each joint so they can be reassembled in the same position. Do note, though, these are the positions of the holes in the mortice, not the tenons. For the draw pegs to work, the hole in the tenon has to be offset by about 1mm (3/64in) in the direction of the tenon shoulder. When the tapered peg is hammered in, it will 'draw' the joint up tight. While the frame is clamped up, the exact size of the Hayrake can be measured and a template made in MDF of the stretcher framework.
FrameOnce the Hayrake framework and dovetail for the legs are cut - see main drawing - the whole frame is dismantled and fine sanded. The chamfers are routed using a bearing guided 45 degree chamfer cutter.
The underside of the top rails and the edges of the legs are all stopped chamfers and are marked for length before routing. The ends of the stopped chamfers are trued up with a chisel either using a guide block or free hand to a marked 45 degree line.
On the hayrake the chamfers are continuous. The 90 degree and 135 degree angles are squared off with a chisel. The 45 degree corners are finished with a small fishtail carving gauge. A V-grooving cutter is used to rout the detail around the feet. The legs are clamped together and one side of all four legs is routed in one pass. This operation is repeated for all four sides. A heavy chamfer is machined around the bottom of the legs to allow for easy movement across a carpet and give a slight visual lift.
The bases of the guide rail notches are cut with a morticer but a router would do as well and the remainder removed on the bench saw.
After a final check, the frame is ready for assembly. The top rails and legs are first glued into two sub assemblies and the end rails and Hayrake assembled in a third operation. The guide rail box is screwed in to complete the frame. Once everything is cleaned up, coat the whole frame with white spirit to check for glue marks which will show up as pale patches.
The top of the frame is planed flush. The T-section rails are made up allowing a 2mm (5/64in) margin above the top of the frame. These are then fine sanded and waxed and checked for fit. Any high spots in the notches will be shown up by the wax and can be eased off.
TopsOnce the rails are moving in and out freely, the tops can be planed to a tolerance of 1mm (3/64in). It's important that any future movement in the frame or table top, or settling to the floor, does not cause the top to bind on the frame. The tops are fitted with screws on the inside ends of the guide rails and slot screw blocks on the outside ends. An expansion plate is fitted at the centre of each guide rail. These also act as stops, preventing the tops being pulled out too far.
FinishingI'm under no illusions about the working life of a family dining table and have finished this one accordingly. A piece of furniture like this should be associated with friends, children, enjoyable meals and celebrations; not endless anxiety about damaging the precious thing.
Consequently I gave it three coats of polyurethane: the first two thinned with white spirit, the final one applied with a rubber and full strength. These are gently cut back between coats. Danish oil - three coats - is applied with a rubber at 24 hour intervals. After three to four days, the top is burnished with 0000 wire wool and dressed with Danish oil.
I recommend a bi-monthly dressing of teak oil on table tops. I've found that polyurethane is flexible, so does not chip or craze and has excellent heat and moisture resistance. It also has UV protection and wood does not darken as much as it does under a pure Danish oil finish.
The legs and frames do not need quite so much work, a sealing coat of polyurethane and two to three coats of Danish oil will suffice.