Bicycle Chain Z-lift?
I’m pitching one of my kid’s crappy Walmart bikes and am looking to recycle any parts possible and come to the chain. @Shauki’s designs use chain parts all over for connectors and spacers and the like, but I was wondering if using them to drive the Z-axis was something that’d been tried and rejected years ago? There’s this: http://www.thingiverse.com/thing:197896/#files
Which could be adapted to a Nema17 shaft, I’m sure.