Our foldable kitchen chairs tilted sideways too easily and were a bit dangerous, so we printed these to make the chairs more stable.
No assembly required, the model will snap fit on chairs whose tubes are 22-23mm in diameter.
You will need to modify the FreeCAD file if your chair has different tubes diameter.
Printed in PETG at 0.20mm, 30% infill, no supports required.
The author hasn't provided the model origin yet.