Have you ever sat in a chair where one leg is just a little bit shorter than the rest causing an annoying rocking? Well these PLA and TPU 3D printed parts fit over the feet of a chair to ensure the legs stay level and even. School chairs and desks often become uneven over the years causing frustrating wobbling for many students. Our design allows for a cheap and durable solution to this common nuisance.

Supplies

Here are all of the supplies/tools we used:

Chair with uneven legs
Calipers
Computer for CAD modeling
3D printer (specifically a Bambu Labs X1 Carbon)
PLA 3D printing filament
TPU 3D printing filament

Step 1: Brainstorm/Design

At first we had to brainstorm a design to use. We proposed adding disc shaped rubber spacers under the chair feet and using adhesive to attach them but we thought this would not be very durable, especially if chairs/desks were slid across the ground (Image #1). We then thought of attaching the rubber spacers to the chair through the use of a plastic shell that could fit over the feet of the chair without the use of adhesives (Image #2). Our last design didn't use any rubber, but instead used one piece of plastic with curved arms that would slightly bend while supporting the chair (Image #3). This would allow the uneven legs to passively gain more or less height as the plastic is bent.

We ended up settling on the second idea due to its durability, simplicity, and smaller size.

Step 2: Finalizing and Printing the Design

We finalized the second design by measuring the exact dimensions of the chair we wanted to fix and applying these dimensions to our CAD model. This design allows us to vary the amount of rubber used to alter the height of the chair using specifically size rubber disks that fit inside the plastic attachment. For this chair, we decided to use two 0.25 inch TPU disks.

The design was then printed in PLA and TPU 3D printing filament on a Bambu Lab X1 Carbon 3D printer.

Step 3: Testing and Demonstrating

Once the design was printed all we had to do is test it out! The PLA shell allowed for a snug fit over the feet of the chair while being durable enough to support the weight of a person and sliding of the chair. We could finally say goodbye to that pesky chair wobbling!