"Uniform circular motion into reciprocating linear motion, by means of a mutilated pinion, which drives alternately top and bottom rack."
Instead of brass I made my rack out of a graphene sheet, carved out to make two rows of linear teeth and end points. I capped the exposed inner carbon atoms with nitrogen. This was inspired by the nitrogen caps I used for the clutch plate on the simple nanotube clutch. For my "mutilated pinion" I inserted a pre-made carbon nanotube from the parts library. I transmuted six carbon atoms from sp2 to sp3 and place one oxygen sp3 atom across each carbon couplet to complete the pinion. To keep the rack aligned I placed four additional graphene plates with multiple anchors around their perimeter.
I guess some more alignment plates are needed? My favorite part is when after the rack flies off, all the hydrogen atoms go flying too; I can almost hear them go "Boing!"