Yes, it is apparently possible to build a working 3D printer out of Lego blocks! Don’t believe us? Check out the link below to Instructables, where Gene Hacker provides a step-by-step process for creating the device.
Interestingly, he used a Polar coordinate system rather than the traditional XYZ scheme, because “I didn’t have enough Legos to build a Cartesian printer”. As they say, necessity is the mother of invention.
Via Instructables
Back in March 2001 Elektor Electronics provided an article on a polar based PCB drilling machine. The drilling arm moved on an arc and the PCB was rotated on a table. There was also a clever thin gearing system for moving the table. It had a ratio of 231:1 in just one stage (a stage consisting of 2 gears and 2 annular gears) with 60:22 and 23:63 teeth. ref: VDI 2157