David Barron does battle with a 2.4m long slab of oak to create a bench with a difference
I first discussed this project with a good customer several years ago; it was one of those non-urgent jobs. The brief was to make an attractive bench which was to live under a large, deep window. It was to be used occasionally for large dinners to seat four people, so it had to be comfortable and fit in height-wise to the existing table and chairs.
With a top of 2.4m long x 50mm thick, I was restricted to using timber from my stocks, especially as the board needed to be clean. I had some very large boards of figured oak buried at the back of my wood store; this is the hardest and heaviest oak I have ever handled. The board in photo 1 was 2.44m long and more than 0.6m wide and I had to drag it along the floor to get it into the workshop and trim it upright with a sabre saw to reduce it to a size I could get on my 405mm planer. After two hours hard labour I had converted the massive plank to a clean square board ready for the top to be shaped.
A convex top
Leaving the top of the bench flat would certainly have saved a great deal of making time but it would not have made for a very comfortable seat. I decided to go for a convex top rather than the usual dished chair design, and this shape is surprisingly comfortable. I marked out the curve on both ends with a template and marked the depth along both of the long edges. If the board had been smaller I would have used the planing machine to remove the bulk of the waste but as it was, an electric hand planer had to be used. Once this had been taken down to the lines all round I turned to my No.7 hand plane to refine the curves and remove any track marks. This was followed up with a Stanley No.81 scraper to remove any tearout from the figured grain.
Achieving even cures
At this stage the surface was clean but the curve wasn’t even across the board, so I turned to my random orbit sander with an 80-grit disc. I kept working this across the grain until the curve felt smooth to the touch. This took about 45 minutes of more hard work and used up about 10 sanding discs. I don’t normally use 80 grit as it leaves some deep scratches which only have a habit of showing up when the finish is applied. So I worked methodically through the grits taking a lot more time than usual to try to avoid this happening. The effort was worth it as the curve ended up smooth and even down the length of the board; and it also felt comfortable to sit on!
The base
Next it was time to look at the base. I had an idea of the position for the two slab legs which needed to be between the legs of the two diners sitting at each end of the bench; however, before deciding on the exact position I put the top in place and stood back to have a look. I try never to stick rigidly to my drawings. Once decided I could cut the oak rail to length, allowing for the tenons plus 5mm each end
to be trimmed off later. I had in mind to use a blackish timber for the legs which would contrast nicely with the oak, and found some suitable wenge from Timberline.
I trimmed the wenge so that the arched grain was central to each leg for a balanced look, a little wasteful but worth the effort and cost. The single rail was attached to the legs with wedged-through mortise and tenons for strength as well as looks. I had originally thought to use pairs of tenons but realised that this would be in conflict to the grain direction of the rail and legs, so I used a single tenon and positioned it close to the top of the rail. This meant that any contraction of the rail would not leave a gap between the underside of the top and the rail.
The Barnsley way
With just one tenon and a single rail the joint needed to be as tight and firm as possible. Since being shown how they execute this joint a few years ago at the Barnsley Workshops I have used their method ever since. I marked out the mortise on both sides of the legs and then used the router with a fence attached coming from both edges so that the mortise was centred. I also worked from both sides to give a clean finish and to cope with the thickness of the wenge. The round ends on the inside were squared off with a chisel.
The outside of the mortise was flared to accommodate the wedges and this needed to be cut accurately. I drew the angle of the flare on paper and set my bevel gauge accordingly, this was then used to sight the angle of the chisel when making the chopping cuts. The tenons were cut on the bandsaw to keep the cheeks exactly square. The tenons were skimmed with a shoulder plane until they were a nice tight fit in the mortises and the ends were chamfered to avoid break-out on assembly. The cuts for the wedges were made evenly on both sides of the tenons and they were angled outwards so that the wood bent easily when the wedges were inserted. This method doesn’t weaken the joint as you may think, but it allows the wood to fill up the flared mortise without undue force.
Little details
The wedges were made at exactly the same angle as the flare and were cut on the tablesaw using the bevel gauge to set up. They were cut to exactly the same length so that when they were inserted by the same amount the result would give an even look to the joint. The wedges could be inserted and all the dimensions checked before putting the joint together for real. I used Cascamite glue which needs to be carefully weighed and mixed with water; it dries rock hard and was the favoured type of glue at the Barnsley Workshop. With all this attention to detail it was no surprise that everything went together nicely and the resulting joints looked good as well.
I put a curved chamfer on the bottom of both legs with a spokeshave to echo the curve to the top; it was a subtle detail but it didn’t take long. As the bench was to be sited on a wooden floor I drilled two very shallow holes under each leg to take adhesive felt pads. This would stop the annoying habit of these pads coming off. These little details were done before the rail was glued.
Attaching the top
Attaching the top was achieved with a mixture of dominoes and pocket hole screws. It would have been best to use wedged through tenons for the top as well but I wanted an uninterrupted finish for the figured oak. With hindsight I could have used ‘foxed’ wedged tenons which use the same wedged principle but are inserted into ‘blind’ holes. If you use the same level of accuracy as detailed here, this potentially risky joint should be no problem. As it was thecombination of the dominoes and screws were plenty strong enough and the grain of the legs and top were in harmony so there were no issues there. I hadn’t used pocket hole screws before and they worked accurately and well. The walnut plugs for the screw holes were not as successful and required filling for a good finish.
I used Osmo Hard Wax Oil – satin/matt – for all parts and the legs, rail and underside of the top were given three thin coats before assembly. I gave the top four ragged on coats cut back with 600 grit between. Applied thinly it gives more of a stain/gloss than a satin/matt so the fifth coat was mixed 50/50 with the Osmo Matt. This gave a dull sheen which is exactly what I was looking for.
While I was pleased with the result, I was glad when this project was out of my workshop; my equipment, space and manpower – me! – were stretched to their limit.
