Enhanced penholder for SphereBot

thingiverse

The pen lift mechanism elevates the pen perpendicularly, allowing for precise straight lines on an egg. To achieve this, I utilized 5mm plywood and a Teflon (PTFE) rod for a smooth bearing. Drilling a hole in the rod to accommodate the pen is crucial; it should be snug but not too tight. A lathe was necessary for me to fine-tune the diameter of the pen. Additionally, a small spring is required to retract the pen. Lastly, assemble the components as depicted in the image.