I recently repaired our lawnmower and thought I’d share some pictures of it.
The gasoline powered push mower is front wheel driven via ring gears that are part of the plastic wheels.
As you can see in this picture, some of the teeth inside one wheel stripped which is really annoying because the driving power cuts out half of the time.

To fix this, I decided to replicate this section of the ring gear with my 3D printer and glue it into place. I took some measurements like the diameter and the tooth count and generated the gear profile using this online tool. Then I imported the resulting SVG file into Fusion 360 and created a part that could replace the old teeth.

This is the part I ended up with. It was printed in black PLA on my Ender-3.

I then removed the old material from the wheel using a Dremel and some hand tools. This took more time than I anticipated. If I were to do this again, I would make the replacement section thinner so less material has to be removed. Anyway, this is how the inside of the wheel looked when I was done with this step:

Afterwards, I glued the new gear section in using some two-part epoxy. The end result can bee seen below. I’m quite pleased with how it turned out and so far it has been holding up great. If you found this small repair interesting, stay tuned for my future projects!