[budadre75]

metal gear to metal shaft first, then attach plastic gear for further reduction? Also the article mentions metal-core plastic gears.

[justinator]

I guess then - why not go all-plastic, or all-metal. I fear that if there's large differences in temperature, you're going to start having a really bad time.

[tripletmass]

You can for that matter pick a glassy self-healing core near the appropriately made metal shaft, continuous rubber as you fill out the radius, and coated harder (UHD) nylon at the outer, but who's to care to make it like that? Ship it with the dough hooks, maybe.

Or as you suggest, printing open-grid metal-inclusion ceramics could go swimmingly for the less green home refactory applications. There goes little Sigfried, recasting his molybdenum iWatch band with the concentrated symmetry-breaking solar from the shed.