Thoughts & Ideas

The Cabinetmaker’s Ultimate Challenge – Part 2

As explained in Part 1, we set ourselves the challenge of designing a dining chair. In doing so, we will be trying to find the ideal balance between comfort, strength, lightness, style and cost.

Where to begin? There are certain design features that are predetermined – A dining chair seat is normally about 450mm high and is usually a little lower at the back. The back supports should curve in a little to support the sitter’s back but should curve outwards at the top to be comfortable at the shoulders.

Chairs can be made using many different materials but we’re keen to have our chairs made predominantly out of wood. Timber is our material of choice. We’re always keen to promote the use of our own locally grown timber so these chairs will mostly be made using Aberdeenshire hardwoods – principally Oak, Ash, Elm and Sycamore.

Graeme Winram has spent many evenings looking through his collection of furniture making books, absorbing the different design options and working out which elements could be adapted to suit our own design. He has always liked the curvaceous and ergonomic chairs of Sam Maloof but that style is very time consuming to build. He loves the simplicity of George Nakashima’s Conoid chairs and the characterful personality of David Savage’s Love Chairs…

We keep coming back to the cost though. We don’t want to make chairs that are fabulous but out of reach for most people. So the design has to be made with machine production in mind. We can’t have the guys in the workshop carefully spokeshaving every component into beautiful organic shapes because that would take days to produce. Our chairs will need to be produced using carefully designed jigs so the shaping can be done on the spindle moulder rather than by hand. The joints will need to be strong, simple and quick to make. We’ll use the classic mortice and tenon where required for maximum strength but some of the joints can be made using the Festool Domino Jointer.

One of the attractions of chairmaking is that it requires a large number of relatively small components so it’s a great way to make use of the timber off cuts we produce.

Every designer has their own method of coming up with a design. Some work on the drawing board, others on the computer. Some go straight into construction and just make it up as they go along. Graeme is always scribbling out ideas on scraps of paper and he has ended up with a folder of sketches. Over time, the main elements of the design become clearer.

The seat will be curved for comfort but we don’t want to make classic carved Winsor seats as it’s hard to mechanise that process. We don’t want to use laminations of bent plywood as we like the integrity of solid timber. We ended up with the concept of building the seats using five separate slats of timber. Each one will be curved to a comfortable shape and they’ll be dowelled together. This is a system that can be adapted for batch production. We like the idea of keeping a small gap between each slat. It’s a small detail but we think it adds to the design. The seat is simply screwed in place through the frame below. This means it’s simple to supply the chairs with a timber or an upholstered seat

We like the idea of having the two back legs quite close together and also parallel rather than splayed apart. The joinery becomes simpler as the joints are set at 90 degrees to each other. The design of the back splat and the crest rail are very important as these components contribute greatly to the style of the chair. We spent a long time experimenting with different crest rail shapes. Each option seems to give the chair a different personality.

For the crest rail, we felt drawn to the last shape on my sketch with a straight bottom edge and a concave upper edge. An artist friend of Graeme’s commented that it resembles the traditional Torii Gate of Japanese Shinto Buddhism.

The Y shaped back splat evolved by extending the crest rail design. Graeme simply sketched out a shape that suited the rest of the chair and ended up with a water diviner’s dowsing rod which gave the chair its name.

As the design takes shape on paper, we moved to full size elevations on a large sheet of plywood. This provides us with the actual size of each component so we could come up with a cutting list. Looking at the design in full size does throw up some unexpected design issues so we need to make changes as we go.

The Mark One chair was made using Ash – just because that was what was easily to hand. There’s no point in carefully jointing the components at this stage so everything is simply screwed together. Similarly, we don’t spend time making assembly jigs at this stage. It’s better to quickly assemble a fairly basic version. This will really let us see how the proposed design works in three dimensions. No mater how much time is spent at the drawing board or on the computer, it’s only once that first full size version is assembled and we get the chance to walk around it, looking from every angle, that we can finally say, “So, that’s what it looks like!”

The next stage is to see what it feels like. Straight away, we can feel the parallel back legs don’t feel comfortable. They need to conform to the 650mm radius of the crest rail. This means that the front edges needs to be reshaped to a 10 degree bevel. The seat feels really quite comfortable but we find it feels even better if we raise the front edge by an extra 12mm. This tilts the body slightly back against the crest rail which feels more supportive.

Both these changes make for a more comfortable chair but they also add to the work and therefore the cost. This is the kind of dilemma we face in furniture design – where do we find the right balance between cost and comfort?

There are several small changes that need to be made but in general, we’re really quite happy with how the Mark One chair is looking. The next stage is to put together a Mark Two version. This will be take account of the changes and we’ll build this one properly jointed together. We’ll also finish it with a hardwearing satin lacquer. We’ll prepare three seats – one in lacquered hardwood, one upholstered in fabric and one upholstered in leather.

To find out how we got on and to see photographs of the completed chair, look out for The Cabinetmaker’s Ultimate Challenge - Part 3….