With adequate pride, I wish to present my latest design in chair making!
Some parts will prove trial and error, such as the flexibility of the front to the back. I wonder whether it might start ‘walking’, as the parts bend and flex.
Otherwise I’m excited, as I know it’s going to be quite a challenge.
I next step is making the lamination clamps!
Above, you can see a calculation of the amount of springback, when compared to the amount of laminating layers.
So 10 layers divided by, 40mm of displacement = 0.2mm display.
With my pressing mold finally working, I stumbled across a major structural issue: that it is actually WAY too flexible…
I have done some basic stress calculations, but think I will need to just experiment most of all.
As you can see, a similar wood birch will flex immensely.
The original 9 mm will flex nearly 9 cm!! But when I brought this up to 15 mm, the sag is way less. My plan is to actually try and switch the grain on some layers.
So this is what I am up to today! 🙂
Wish me luck 😀
For the next trick, i cross grained my different layers of wood, and in stead of 3 I used 5 layers. Summing up to a total of 15mm instead of 9.
The cross graining is a technique used in Multiplex, to assure plate stability and rigidity.
By starting with a layer that bends in the cross direction and then a layer that bends in the length of the shape, and so on, they both keep each other from bending.
Additionally, I made sure the majority didnt bend in the length, so it looked like,
Looking, and feeling as hard and rigid as a plate of 15 mm multiplex! but then round! 😀 very pleased with these results.
Now, as the wood process is a working one, i can move on to thinking about the fabric part.
as I have planned, I printed the basic fabric shapes I had designed, and went to work from there.
Now I have my basic fabrics cut and sewed together, I can get to work on the padding, next you see some of my experiments, to get a bit of a feel of what its going to be like.
As it turned out, just one layer of 200gram Dacron fibre was enough to give it that lush puff, but still not too thick for my sewing machine to handle. Consistent results on the stitchlength and tension are as allways with sewing, of dire importance.
Next up, the edging. I wish to run a cord through, to distribute the weight to the ends of the rope.I decided to use fake leather, as it was all my budget at the time would allow for.
after trying several widths and colours, I tried a break test, and it held up quite well, but once it started ripping, there was no hope left.
Not a good quality for a chair. So I made sure it was backed by an extra layer of fabric. Then I sewed it all together.
Giving it some nice padded sewing lines.
And then back to the wood part of the process!
Picked up some gorgeous Elm, Amsterdams most beautiful wood, and set to work making it into nice planks. Then i glued them together as bars of 80x80mm, to work down to a total of 75x75mm.
As is visible throughout my design process, I have been of two minds whenever I thought of the front legs. On the one hand I really liked the heavy front, just huge blocks of legs, in contrast to the springiness of the back legs.
But also I made plans to do the classic cabriole leg, which I sort of left as a thing if i had enough time.
Leaving that to lay for a little longer, i made all the connections in the wood, and drilled a wide hole for the bumbone. (the lower laminated curve)
Back on the home front, I had received my new parts.
Not able to resist, I had to try the parts temporarily with clamps.
what an peculiar shape!
seeing this, I definitely felt the front needed more form-definition, and also a bit more sexyness.
So I decided to roll with the Cabriole Legs!
and also made a basic temporary armrest sketch.
I also considered trying the armrests as blocks.
Very pleased about how the legs curve and feel ready to jump into the air.
This binds it in visually with the back.
Also seeing this, I realized blocks wont do, and as i wanted the front of the leather strap to be as wide as where it attaches to the back, this 3D armrest design would not do.
After thinking for some time, I drew a mirror image of the cabriole leg, and also tried ways of making the shape stronger. After some google reasearch of archetypical classic design shapes, I quickly realized what I was aiming for was a Lyre shaped armrest.
Taking inspiration from it,
I added a ball to the top, and presto!
So i have been very busy the last week.
Lots and lots of exams for school, and of course, the chair!
on the side I secretely experimented with decorative nails ad ways of attaching leather to my wood., for the armrests.
Glueing the laminations.