Tuesday, June 29, 2010

Stylish Bench from Walnut Slabs

One of the great things about making wood furniture is that sometimes you get the chance to let nature do most of the work - then all you have to do is add a little bit here and there, and you get a great looking piece. This bench is just such a case. The walnut slabs, sourced from an orchard in the San Juan Bautista area, are the real star. All I had to do was add a little styling in the form of legs, and voila. It got a great response at the Marin Art Festival, and now is available for purchase. It measures roughly 70" long x 35" high, x 28" deep.

This is a look at the back and leg structure.

As you can see, the material speaks for itself.

Tuesday, June 15, 2010

Designing for Movement

Even though its been dried and milled, solid wood lumber still experiences expansion and contraction with changing environmental conditions. This movement must be taken into account when building furniture because if seasonal movement is restricted, the internal forces brought to bear can cause cracking and splitting. The challenge with this piece was to come up with a joinery system that would allow the spare design, just two slabs and two leg assemblies, to be strong and rigid, while still allowing movement of the slabs. Because the grain orientation of the seat and back supports are perpendicular to the grain of the slabs, simply doweling, tenoning, or screwing the pieces together would not allow the slabs to move, and result in failure. The answer that best suited this project was to attach one edge of each slab with a mechanical fastener (aka, a screw), and the other edge with a form of sliding dovetail, known as a blind keyhole dovetail. In this type of joint a dovetail-shaped tenon fits into an elongated sloped-sided mortise - the dovetail shape keeps the slab firmly snugged to the leg structure, but allows the slab to expand and contract by sliding along the tenon.

This is a picture of one of the mortises. You can see that half the mortise is square in profile, to allow the tenon to be inserted, while the other half is dovetail-shaped.

This photo shows one of the back supports. You can see the attachment screw near the top of the support that is the fixed attachment point, and below it the hard maple dovetail tenon that will slide into the blind mortise. To the left you can see the other leg assembly already attached to the back slab.

This next photo shows the similar arrangement for seat slab attachment. You can see that the front of the seat slab will be fixed, with the rear of the slab allowed to move in and out.

Here is the fully assembled bench (upside down) showing the slab-to-leg assembly attachments.

Stay tuned for more images of the final, finished piece. Thanks!

Thursday, June 10, 2010

New Bench Project

With the Marin Art Festival coming up fast, I wanted to create a new piece to show at the festival. I've had a couple of matched walnut slabs from an orchard near San Juan Bautista for a few years, and have thought from time to time that they would make a great bench. So, this seemed like the time to get off the stick and make that happen. I'm going to keep the slabs in as raw a form as possible, in other words, not hiding the worm holes and checks. To counterpoint that roughness, and give the piece a little sophistication, I'm going to use wenge for the sculpted leg structures. Although I wouldn't be so bold as to suggest that my work is at their level, I think of this as a sort of a Kagan meets Nakashima design. Hopefully, I can get it done in time!

Here's a picture of the slabs and the leg blanks. You can see the final leg form from the plywood template. The slabs will be attached to the flat seat and back surfaces. Notice the great colors in the slabs that have been preserved by letting them air dry, rather than kiln drying. The only down side to air drying is that the moisture content of these pieces is only down to about 9%, which is a little high for furniture. So, I'm going to have to design joinery that will allow for extra movement.