Attachable Cushion+Back Rest for Stool

by Shahid Maniar in Workshop > CNC

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Attachable Cushion+Back Rest for Stool

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When I first entered the new school year as a new student at Metro Early College High School, I was greeted to a new building. It was bigger and included a workshop for students to use to build projects for school or otherwise. However, a few days in I, along with many of my classmates, noticed a big problem. There were no chairs, only stools! At first, this wasn't a major issue but as time passed we noticed that the lack of a back to the stools was causing significant back pain overtime and the lack of a cushion on the metal chairs was causing immense discomfort as we would sit in class for nearly 3 hours every day. So me and my friends Jack and Sudman devised a strategy to actually build an attachable seat cover that would solve the issue plaguing us.

Supplies

  • Fusion 360
  • Plywood 
  • Wood Glue 
  • Velcro Adhesive Tape
  • Sharpie 
  • CNC machine (could easily use something else but we had access to a CNC machine at school which helped speed up the process)
  • Band Saw
  • Sand Paper (60 grit or higher) 
  • Latch (3) (PLA filament) 
  • Bolt Cutters
  • Prusa Slicer

Sketch Ideas and Measurements in Notebook

Back.jpeg
Full Diagram.jpeg
Seat Bottom.jpeg
Concept 1.jpeg
Concept 2.jpeg

After coming up with the idea to make the attachable back we experimented with a multitude of ideas before eventually settling on the one we decided to go with that involved attaching the seat to the stool with latches. We then dimensioned the stool and made plans on the material we would use for the various parts like the cushion, cover, and filament.

Model in Fusion 360

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Before actually modifying and plywood we modeled all the pieces in Fusion 360 to see a general overview of how it would look. We also imported a latch model we imported the latch model but later modified it before 3d printing to fit the needs of our project

Making the Back

Sudman Sanding.jpeg
Back pic.jpeg

After modeling the pieces in fusion 360 we picked out the pieces of plywood we would use we first started on the back of the attachment. For that, we used wood glue to glue 2 pieces of plywood together then sanded it down for a few hours until we got the shape we wanted. The shape was modeled to give back support to the natural curve of the spine.

Making the Seat

For this step, we used a CNC machine to speed up the process. We CNC'd two different pieces then glued them together The reason for this is we needed a thicker piece of wood so the cushion would have a deep enough pocket to stay in to be comfortable. The first piece had a cavity taking up most of the space. The second piece had the same dimension but without the hole it also had a socket so the back could easily slide into it.

Aseembly

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Chair Done.jpeg

For this step, we glued the back and the seat together then nailed them for extra support. We had to use bolt cutters to get rid of the pieces of nail sticking out of the back before filing them down. We then sanded everything down to get rid of the possibility of splinters. Then we stuffed the Velvet Dining Room Chair Seat Covers with Polyfil to make a cushion for comfortability. Then we attached part of the latch to the seat with adhesive velcro and the other half to the seat to make it easily attachable and detachable.