Friday, March 13, 2009

Chair of the Board

Client C, who generously gave me the opportunity to make the pentagonal table and step tansu described in previous postings on this blog, also required a set of dining chairs, to seat five. Chairs are something many furniture makers avoid tackling, apparently, however I didn't know enough about furniture making at the time to be hesitant in that regard, so I plunged right in.

When you study chairs a while - and I recommend Galen Cranz's book "The Chair" (1998) as an excellent resource - you will find that it isn't actually possible to create a chair that is comfortable for the human frame. Not for a long sit anyhow, humans simply aren't meant to sit in chairs- nature evolved us without attached chairs (what was she thinking?!).

Chairs that look cozy and comfortable to sit in, inevitably must provide inadequate body support, and thus fatigue the sitter by placing stresses on their skeletal system. Chairs need to allow the sitter freedom to shift position, which is necessary, just as when we sleep in a bed.

At the time I made the chairs for Client C, I was laboring under the delusion that I could make an 'ergonomic' chair that provided some balance between immediate comfort and skeletal support. Any such attempt is really a compromise at best, since no chair can be comfortable ultimately, however in this case it was very much in my favor that these were to be dining chairs. A dining chair should not allow the sitter to recline too far back, as the physical effort of bringing the torso back and forth to the plate is tiring after a while. Since a comparatively short period of time is usually spent in a dining chair, as compared to a sofa or recliner, etc, the dining chair can be made with greater emphasis on posture concerns than long-term sitting comfort (which isn't really attainable anyhow).

I suppose a lot of furniture makers avoid chairs because in their construction, they necessarily feature curvilinear parts, in most cases, especially if they are to look non-clunky, and conform somewhat to the human form. Also, while it is easy enough to make a very strong chair, since the chair user at a dining table slides the chair back and forth quite frequently, no client is going to appreciate a heavy chair. Like the vanity I described in an earlier thread, the challenge with a dining chair is to make it both strong and light, and look nice, and be comfortable, and give good support for the duration of use. That's a lot of challenging requirements to meet - chairs are probably one of the most demanding pieces of furniture to construct successfully.

I studied a lot of chair designs before starting in on these ones for client C. Having, like most people, experienced chairs that were coming apart, and threatening to dump me on the floor if I made the wrong move, I wanted to design a chair that would be strong at the critical junction of seat rails to rear legs. This ruled out a design along the lines of the famous Nakashima 'Conoid' Chair, which cantilevers the seat and thus makes the seat-rear leg join even more stressed than otherwise:


I confirmed my impression of the Conoid Chair design when I visited the Museum of Fine Art in Boston (MFA), where they provide chairs by famous makers all around the museum, and you can actually handle them and sit in them. They had a Conoid chair, and sure enough, the seat-rear leg joint creaked when I sat down. It was reasonably comfortable, well made and cleanly finished, but the structural concept is flawed in my opinion - not only in the seat to rear leg joints, but also where the legs attach to the feet.

I admired a chair made by Josh Metcalf, and detailed in the (now defunct) magazine "Fine Home Furniture":


This chair, described in the article as "English Chair, Asian details", elegantly incorporates some features of classic Chinese furniture. I choose to do joinery a little differently than that maker, and have different ideas than about chair ergonomics. Nonetheless, a very nice chair indeed and a source of inspiration.

I also liked the look and construction of some of the Greene and Greene chairs, in particular the ones seen in the Blacker House, made around 1907:


I liked the way the lower cross-stretcher is turned on its side and moved back to clear the diner's heels (compare to the Metcalf chair). I like the tapering of the chair seat from front to back, though I must say, having seen one of these chairs in the New York Metropolitan Museum of art, I find the taper excessive. In fact, 'a bit excessive' characterizes a large part of my take on this chair today.

Years back, I used to really like Greene and Greene, but these days I think it is a bit, well - the brush strokes are a little too thickly painted for my taste. It's seems to me that they borrowed an aspect of the 'Asian' aesthetic and made a cartoon image out of it - especially the little brackets - properly termed 'spandrels' - in the corners between the legs and the seat rails, which are sorta reminiscent of a temple bracket arm assembly. Chinese chairs also feature brackets at these locations on tables, and much in Chinese furniture does derive from temple architecture, however I would argue that the subtlety and beauty the Chinese masters evolved in these details is not met in the Blacker Chair. More than that though, I find the piece a bit loud in all it's exposed joinery - too much for me anyhow, especially when envisioning a room filled with similar pieces. Also, I know that some of the exposed pegging actually is either strictly decorative, or conceals screw holes, which goes against the, er, grain for me (I now brace for the howls of protest from outraged readers). I like a peg that you can see to actually function as a peg.

Still, Greene and Greene pieces are revered and much-copied in North America, and I very much admire their holistic approach to building. I'll talk about that more in an upcoming post.

So, here goes some photos of my first set of chairs, the only ones I have made thus far.

Since the pentagonal table was made from Mahogany and Pacific Yew, it made sense to use the same materials, and incorporate similar stylistic cues, after all the chairs were to be used in concert with the table.

The side rails of the seat, like the stretchers of the table, have beaded and rounded lower edges, the pieces carved from solid. The most stressed part of the chair is the joint of side rail to rear leg, so I tackled this issue by swelling the height of the rail and forming a doubled tenon arrangement:


Pegs here were made from Wenge, which has a crushing strength of approximately 10 tons.

The connection between rear legs and crest rail I chose to do by means of the double mitered locking joint, which proved to be quite challenging to execute given the thickness of the locking wedges at 0.09375" (3/32"). Here's the rough-cut top of the leg:


A 'before and after' photo:


Here's another view of the completed crest rail joint, crude to be sure, but it proved effective:


I designed the back splats to be flexible, fixed at the bottom and floating at the top, so that when the diner reclined back, the splay would conform to their spine:


Pacific Yew was an ideal choice for the splats, I believe, given its resilience, and I happened to have some really nice edge grain Yew with a beautiful flame-like pattern and fine black streaks on hand at the time. That was really special material, and I haven't come across anything like it since.

One of the chairs was to have armrests, and I connected the arm to the support post using a through tenon, with double wedges to lock it:


I'll save the pictures of the completed chairs for the next post, but here's a sneak peak:


In the above picture, you can see in the lower chair frame, at the seat side rails, the dovetail slots for the armrest support pieces. This is something I borrowed from Metcalf's chair design. I don't totally trust this type of joint in side-loading however, and later opted to reinforce it with a machine screw from the inside - call me paranoid. The next time I make chairs, if there is a next time, I will revisit this area of design which, like the junction of seat and rear leg, is a critical and highly stressed point in chair construction. It requires careful consideration if you want the construction to last, as chairs take more of a beating than any other piece of furniture. I've examined many fine Chinese Qing/Ming Dynasty chairs in the years since I made these chairs, and as a result have some new ideas with which to move forward.

Well, hopefully I haven't repelled too many readers by my early attempt at making chairs - I'm hopeful that with more practice I can improve upon my results.

No post tomorrow as I'm off to the south of Connecticut to look at an interesting potential building project.

11 comments:

  1. Chris,
    I have yet to attempt to make a chair, but chair design and in particular the issues joinery and comfort have been swimming through my head for a while. One interesting thing is that, in seeing photos of 'famous chairs', such as the Maloof rocker, I often wondered about the tenons of, what seemed to be flexible, back slats. In my mind I had decided that, if I ever prototyped a chair, I'd do exactly as you did, that is, to leave the top tenons floating. I thought that was rather clever of me :) and I am pleased to see that it's a viable solution.

    Could you say a bit more about these? Have you found references to them in the chairs of other makers?

    thanks for the stimulating blog :)
    -toscano

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  2. Thanks for the question toscano.

    I can't remember any longer where I first picked up the idea of floating the splats, but it made sense, and even more so in a flexible and elastic material like Yew. i sat in a Mallof chair at the MFA - it was solid and fairly comfortable, however I didn't care for the down-sloping armrests. The best of the bunch though.

    The interesting point that Cranz raises is that attempts to provide lumbar support in a chair, to keep the lower back from rounding as it wants to do when the thighs are placed in an approx. 90˚ position to the torso, is actually not very workable. The more you try to push the lumbar area forward, to keep the back in 'good posture', the greater the tension on the sitters hamstrings, which is uncomfortable soon enough. Again, this is less of a concern in a dining chair because the back of the chair is relatively upright.

    I notice that back splats on most of the Chinese chairs seem to be shaped opposite to mine, to cradle a rounded back. In addition the chairs are designed to be used with foot stools, which would tend to round the back even further as the legs are raised. Hmm...

    It's an an intriguing design challenge, and at best you achieve a compromise it would seem.

    ~Chris

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  3. Uh, that's a Sam Maloof chair, not 'mallof'. I wish these comments could be edited after posting!

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  4. Hi Chris,

    IMHO, you don't need to be (and should not) apologizing for your chairs! I would question the existence of an "expert" chair maker, rather I would lump he or she into an "expert" wood worker. Your projects thus far have handily put you in that category.
    After all, functionally, a chair is a chair (given some variation for design which attributes to better strength/longevity). After that, its just style and cost. Even though the chairs you have made thus far are a first attempt, you have put a great deal of time and thought into the design, both structurally and stylistically and as usual, the craftsmanship is excellent.

    Steve

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  5. Chris,

    I agree about the sloping armrests. They don't seem to make a lot of sense to me, but I think he may not have intended them as armRESTS entirely. He has some chairs, if I recall correctly that have 'armrests' only a couple of inches above the seat and parallel to it (i.e. non-sloping). The idea behind those being that they are not so much rests, as handles so the chair can be moved around and so the sitters can use them to lift themselves up.

    I also wonder what you think of chairs made by Danish makers, such as J.L. Moller and H. Wegner (who, as I am sure you know, has a dozen or so variations on a Chinese chair theme).

    cheers
    -toscano

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  6. Chris,

    one other feature of interest I noticed in your chairs is that the back edge of the seat is not flush with the back but moved forward a little bit. I presume this was for lower back comfort in unison with the back splats?

    -t

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  7. Thanks Steve. I'm working on showing the stuff, like these chairs, that was my first attempt, or was done with no money (like the Cob hut) or where I made major blunders in the estimating (like the deck). I feel like it helps me in other ways to take that risk, and to show that even if I might do one thing relatively well, in other areas I am stumbling around. I'm hoping other people might see fit, by my example, to take similar risks in their own work, and that you don't have to be 'perfect' at anything, simply keen to do your best work. I hope that makes some sense.

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  8. Toscano, i think you've done some good thinking and research into chairs. I agree that the other function, probably the most important, is the use of the arms to help push oneself up and out of the chair. I don't see the reason why they should slope downhill though to accomplish that, and the downward slope to the front seems to fight the overall lines of sight (to a vanishing point, say) generated by other parts of the chair.

    I moved the rear seat rail forward NOT to allow for lower back comfort with the splats, but to remove the need to add cross-wise mortises at the connection of the side rails to the rear legs, the structurally vulnerable spot of the chair frame. Even if I did place the rear seat rail through the legs, that portion of the seat immediately under the rail isn't usable anyhow, so it made sense to move the rail forward and go for strength in that area or the rear legs.

    ~Chris

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  9. Nobody starts out as an expert or doing things perfectly. Whatever standard you decide to compare yourself against, you have to realize that making it to that level is going to take time and along the way there will be less than satisfactory results (well, they may be satisfactory, but always room for improvement).
    In the martial arts, we are taught that making a mistake (i.e., doing something the wrong way) is valued because it is the only way to learn to do something right. Losing a match is irrelevant. It is being allowed the chance to see what was necessary for success, and learning (trying) to do it that way. You know,... we could fill pages with cliches about try and try again, etc.
    It is the measure of a person who can be shown or discover another way and see the value without feeling ridicule, inadequacy or some loss of prestige, as much as it is to, as you said, to attempt to do something without the fear of the same.
    Perfection is certainly something to reach for, but each step short, like the lost match, is a necessary lesson along the way.
    So I think, "taking risks and being keen to do your best work" is exactly the right way.

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  10. The Pacific Yew spalts (Yew is a local wood for me) are indeed beautiful, but I am also taken with the grain pattern of the curved top rail above the spalts. Were you able to get that effect on all the chairs?

    I also think the exposed joinery of the locking mitre joint adds visual appeal to the transition of grain from the top rail to the back leg, from its side view.

    Marv

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  11. Marv, nice of you to notice that. I did strive to get that pattern in all the crest rails, and was not completely successful. I ended up making more than 5 chairs, as I'll explain when i take this up again tomorrow, and 4 of the 7 had the grain come out as I wanted. 2 of the 7 had a partial patter, and in one chair i got the piece turned around backwards before I ran it through the bandsaw, and the pattern ended up to be completely upside-down. That became my chair.

    ~Chris

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