Michael Thonet Goes With the Grain

The bentwood No. 14 Chair is a chair you know.  It is more produced than any chair in the history of man.  Can you picture it?   It was called "the coffee shop chair" or the "chair of chairs" and below is a photo of one of the 50 million or so produced.

The primary inovation of this chair was the use of complex fixtures and steam bending to create the simple and comfortable light-weight form.  Using this technique, Thonet was able to overcome the orthotropic character of wood by keeping the wood grain all in the same (and stongest) direction.  Unlike metal, wood has dramatically different strength in the different three axis.  The strength along the grain is many times greater than across the grain  or radially.  A bit later, Alvar Alto demonstrated his command of the othotropic material with this chair...

Sometimes woodworkers can get the wood to bend with just steam and some muscle, other times they rely on a process of laminating multiple thin sheets together with glue.  Either way, it demonstates that if one is aware of and repects the unique properties of wood, amazing things are possible!

Turning Japanese

You may  have noticed that The California Workshop appears to have an undeniable Japanese influence.  We don't have Japanese ancestors that we know of but we do have some shared values.  

Woodworking in Japan is a long respected and preserved tradition.  It goes back centuries to a time of woodworking guilds that protected the secrets of their trade.

Why are the Japanese so skilled in this area?   To start with, Japan is a country with abundant forests that encouraged the use of wood as a raw material when masonry was commonly paired with wood construction in Europe.  The tradition of woodworking is unbroken from a time when the use of metal for fasteners or joinery was unavailable.   And over the centuries, Chinese carpenters and their skills and practices were absorbed by the Japanese guilds. Also, woodworking was intimately tied to spiritual practices as shrines and temples were routinely constructed and reconstructed in a diciplined, traditional, and mindful manner.   A perfect storm for mastery....   

In many cases, woodworkers would go into the forest and select a tree for a specific project.  Today there are woodworkers that determine what they will make based on the piece of wood that they have available.  The wood "chooses" its purpose and it is a manner of giving the wood a second life.  While we are unable to do this yet at our shop, we admire and share the appreciation for the tree and the thoughtfulness in execution.

Japanese Woodworking Joint

So back we go to work, striving to appreciate as much as we can of the delicate nuanced skills of a centuries old trade. 

How is it so light and yet so strong?

Using the same "first principles thinking" that the brilliant Elon Musk gives credit to for his many novel and groundbreaking innovations, we redesigned the chair.

In Physics, there is a concept called Area Moment of Inertia.  You don't have to understand the details to understand the concept.  Basically, it is a method of calculating the resistance to forces applied to different cross-section shapes to determine which will provide the greatest stength in a given application. This teaches us that under many common loading conditions, material that is further away from the center of gravity of the cross-section is far more effective than the material near the center of gravity. It explains why a popsicle stick can be easily broken when flat but when rotated up ninety degrees takes on suprising strength. It also explains the shape of I-beams, bicycle frames and just about everything else you see that was designed by an engineer.

How much more effective is material that is further away from the neutral axis?  A lot more.  The moment of inertia is a function of the cube of the distance "d".  This difference is so dramatic that it makes the material that is close to the neutral axis insignificant by comparison.

So, why not remove it then?  

The 9611-010C Chair is completeley hollow. 1.27Kg

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Getting Frugal with Energy & Materials!

Here are the first of the 9711 light fixtures.  Driven by one of the most efficient long-lasting lamps on the planet, these linen/origami shades cast a lovely diffuse warm bath of light.  With a bulb life of 22 years, you may never change the bulb in these lamp!

9711-760 Six drop Chandelier

Large Single Pendant 9711-310

Small Sconce 9711-160

Furniture Means Mobile

I am often asked what the purpose is of making a lightweight chair or table and I usually respond by saying how using less material makes it cheaper to make, ship or relocate. Sometimes I add some comments about sustainability or mention a quote like this one: "Art is the elimination of the unnecessary" - Pablo Picasso  .  But I always fail to mention that the word funiture and mobile are the same in many languages and the fact that mobility is the defining characteristic of funiture.   The word for funiture in Spanish is Muebles (moveables) Here are some other examples:

The word for furniture in French is meubles,  In Danish: møbler, Turkish: mobilya, Italian: mobili, Dutch: meubilair,  Swedish: möbler...you get the idea so lets get moving!

9611-008 Chair

And...two more

The most visisble changes occuring now are in the back rest.  It is a stuggle to find the right mix of comfort, stength, weight and ease of assembly.  Revision "S" below is difficult to put together and isn't that comfortable. Revision "T" below it goes a long way to solving both of those problems but still needs a little more strength.  Back to the drawing board!

9611-009 RevS

9611-009 Rev T, 1.32Kg

It looks the same, but it's different

Each iteration of the 9611 chair solves some problems...and creates some new ones.  Below is an image of the most advanced version to date.  And yes, it still has some details to be worked out but we get closer with every new effort.  

The 9611-009P chair in its natural habitat

Excuse me miss, is this your chair?

No special tools are required to build the lean 9209-009P chair.  Just some glue, some masking tape and some sand paper (I like to use a little brush to move the glue around).  I compressed an hour build time into about a minute.

9611-009K Drops below 1290g!

The skeleton without the "skin".  

The lightest Chair we have made to date.  1290g

We're still learning and evolving.  This chair utilzes ultra-light poplar plywood and has hollow braces between the legs to prepare it for the 113Lb leg test loads it must withstand to comply with the ANSI/BIFMA standard. 

Fast Forward, Dinner for Eight

Chair Numbers two thru eight, each a one-of-a-kind experiment

Hundreds of variations were attempted in this iterative process.  Each chair incorporates dozens of changes from the previous one as we changed the seat, back-rest, plywood material, experimented with lightening strategies and made structural revisions.  The chairs are shown in chronological order, with the closest being the oldest.  Each chair took about a week to design cut and assemble and the weight slowly dropped as we learned where we could remove material.