More ideas from jim
Build guide for an easy to make metric barn door tracker for astrophotography. Cheap and simple to construct with DIY build plans, photo gallery and MP3.

Build guide for an easy to make metric barn door tracker for astrophotography. Cheap and simple to construct with DIY build plans, photo gallery and

Scratch-built hand-cranked gear cutting machine - side view

This is a working wheel cutting engine based on historical designs. "Wheel" is the term that clock-makers use for larger gears, while "pinio.