Submission Day!

After a sleepless night of worrying about the possibility of my stool collapsing beneath me in front for the entire class, I am pleased to announce that it didn't! Coming in at just under 2.5kg, the stool still exceeded the weight limit, but still functioned as a massively over-engineered stool. There were no signs of twisting, buckling, bending or cracking, which was a massive relief, as it was the first time anyone had sat on this stool. The stool is actually more comfortable than an implied seating plane made of metal tubes might suggest. I would consider this design a success, though if I had to redo this stool, I would, as mentioned before, increase the thickness of the plywood frame and do away with the aluminium sheets, in favour of a cleaner aesthetic; tubes that protrude out of the wood, without any apparent fasteners. Having said that, the aluminium sheets do have a certain aesthetic appeal, and when considering the weight constraints of this project, are indeed necessary for load distribution and structural rigidity.

Prototyping Day 3

Today was the final day in the workshop and the last few tasks to complete included spraying WD-40 on the aluminium frame to remove dirt and glue from the frame.

Domino joints were cut using the domino cutter

 The aluminium frame was glued in with Liquid Nails and screwed into place, starting with the standing plywood frame, before applying PVA to the domino joint and Liquid Nails to the lower part of the plywood frame.

Tomorrow when the glue has set, the final part of construction will include sanding the frame to a natural and smooth finish and polishing the aluminium.

Prototyping day 2

Today in the workshop, 16mm holes were drilled into the standing plywood frame, to hold the aluminium tubes. The length of the lower plywood frame was trimmed to account for the offset.

The aluminium tubes were welded through the bottom and angle ground to flatten the base.

Holes were drilled for screws to fit in.

 The above image is of the stool standing on its own, without any glue, screws or domino joints cut.

On Monday the stool is expected to be finished, all that remains is cutting the domino joints, screwing the aluminium frame in, gluing the aluminium to the wood for extra support with Liquid Nails, gluing the domino joint and polishing the frame.

Prototyping

This is the tube bender, which was used to bend 10 aluminium tubes at a right angle. Luckily I was able to find aluminium tubes at a hardware store with a diameter of 16mm and with half of the wall thickness of the aluminium tubes I had found earlier, this helped substantially with the problem of possibly exceeding the weight limit.

Aluminium sheet metal was cut and bent at right angles, to have the tubes welded to.

 I finally received the CNC routed plywood frame I submitted more than a week ago, which I chiseled out of the plywood board. To further reduce the weight, each middle section of the frame is perforated.

 After sanding the frame components, the frame was glued together and clamped for an hour, the two sections of the frame are not glued together, the photo was taken to depict the scale of the final product.

 After foreseeing some difficulties with welding the aluminium frame together (unsightly weld lines, long duration to receive welding instructions from lab assistants, etc.), the prototyping process was rethought to account for the potential of waiting until next week to be able to weld the frame, whilst maintaining the aesthetic of the final product. The solution was to cut 16mm holes in the aluminium sheets and into the wooden frame itself, to allow the tubes to sit inside and be supported by the wood.

 This is not the final prototype, the last three photos were taken to give a representation of the final form of the stool.

Tomorrow in the workshop: drilling 16mm holes into the wooden frame, cutting domino joints into the wooden frame, drilling screw holes into the aluminium sheet, polish, sand, assemble.

After a lot of going back and forth with the design that I happy with a few weeks ago, I managed to refine the design further due to the weight constraints outlined in the brief and also some issues relating to joint strength I may have encountered with the particular shape of the last design.This stool is still expected to be somewhat overweight, I did the best I could by replacing steel rods with aluminium tubes and also drastically decreasing the amount of plywood to be used. The two plywood frames will now connect with a domino joint and a the overall dimensions of the stool remain 400x400x400mm. Construction begins next week.

Rendered Sketch

Scale Prototype

Due to the lack of appropriate materials, the scale prototype does not include the metal rods which act as the seating plane.

This 1:5 scale model is made from a single cardboard net, cut and folded to produce this shape. This model has opened up the possibility of perhaps replicating the net and making it out of laser cut steel for the full sized prototype, instead of wood. The advantage of having a laser cut steel sheet may be in reducing the overall mass and also increasing the precision of hole alignment for the steel rods, by reducing the tolerances often attributed to human error during manufacturing with wood.