Sidewalk Chalk Spirograph

Spirograph gears painted
This summer the folks behind Haha Bird posted about the giant sidewalk chalk Spirograph they had made. It has a large ring gear made from interlocking segments. The smaller internal gears ride on 3 casters each and carry the chalk. I thought the design was great and that we should have our own for The STEAM Carnival. Haha Bird had used a plotter and a jigsaw to cut their gears; I luckily had access to a CNC mill. Continue reading