by OmlOml, published
This is a CNC rocking chair. The bed is made from a single sheet of 18mm Birch plywood and the sides from another sheet of 12mm Birch ply. I was working with "living hinges" made from zig-zag cut wood and wanted to see if a whole chair could be made that was flexible enough to bend around the curved form but strong enough to support a person. The clamping joint and "T" peg that I designed for it make it super sturdy once it is assembled. It is really comfy to sit on and makes a wonderful lounger for watching TV, reading or just hanging out. An extra bonus - the lower bed is at pet-level. The family dog, cat or raccoon (some families are bigger than others!) can enjoy the ride with you!
I used a Shopbot to cut this chair out it out. The file took 10 1/2 hours to cut/print so be prepared to monitor it for a long time! I used a combination of 3mm and 6mm end-mill bits to cut out the upper bed (used the 6mm on the interior of the ends of the upper bed [ON THE LINES] and a 3mm bit on the exterior profile[OUTSIDE THE LINES] and the middle of the upper bed [INSIDE THE LINES]. For the bottom bed and the sides I used a 6 mm bit to cut the outside profile [OUTSIDE THE LINES] and the interior cut-outs [INSIDE THE LINES] ). I cut the upper bed in two phases: PHASE 1: cut out the pocket for the "T" notches (located at the outside ends of the ribs - they look like a square with mouse-ears on two of the corners) on the back of the sheet of ply used. (to do this I had to carefully set up the board so the Shopbot drilled placement holes in the center line and corners of the sheet. I used these to locate the board in the same position when I flipped it to begin phase 2. PHASE 2: Flip and align the plywood; Cut out the interior pocket cuts for the "T" joints; Cut the interior cavities of the pattern; Then cut the outside profile. My settings for the Shopbot were: Feed: 60, Plunge: 30, Passes 5, RPM 12000. The Pockets of the clamping end of the "T" joints were set at 9.25mm deep.
I only used a 3mm bit for the sides and the lower bed. I chose the 3mm bit because it gave a cleaner cut but it does take longer!
When you have cut out the four pieces you will probably want to lightly sand off any splinters from the cuts.
I assembled it by first laying the lower bed on a table and placing one of the middle "T" notches in the clamping joint. To do this I used 4 Irwin brand quick clamps to open and clamp the joint into place. This process took some time and it pays to go slowly so that you don't damage the parts of the chair. after working the first side into place I then set the lower bed on a low stool and let the assembled side rest face down on the work bench while I worked the second side into place using the same process - start in the middle and work to the ends
With the bottom assembled I set the partially assembled chair on a table and draped the top bed over the sides. Again, I started in the middle of the bed and worked toward one end then the other using the quick clamps to open the joints and slip them into place over the "T" notches. The only part that was assembled out of this order was the end with the tightest bend. This end didn't look like it would make the turn if the last clamp joints were connected. I put this in place after I fixed, by hand, the connection problem I mentioned in the warning section above. There are some pictures of the assembly process and the design process at: http://therchair.wordpress.com
This chair was inspired by: the Frank Lloyd Wright re-designed chair made at the Makelab ( http://makelab.wordpress.com/2012/05/08/dining-chair-inspired-the-wright-way/# ) , "Relax" rocking chair by Vernon Panton in 1974, and the work of Gregg Fleishman ( http://www.greggfleishman.com/furniture.html )
Special Thanks to the Fab Lab Wellington and to Massey University for the use of their facilities. https://www.facebook.com/FabLabWGTN
or see their thingiverse page: