small electric drill made from a pager motor, about 2cm tall. #small
on 02025-06-17#Chronova hand #manufacturing an electric motor whose shaft is 90μm across, like William McLellan’s answer to Feynman’s “Lots of Room” challenge. It’s a permanent-magnet rotor nestled in between four straight electromagnets wound with 20μm wire. He kept losing parts. He spent several months on it. His soft iron rotors had coercivity that was too low, and #machining alnico on his lathe turned out to be impossible until he used grinding wheels. He finally gave up and just floated the alnico disc in watch oil on the other side of a cover slip. He got an electromicrograph. #small #motors #hardware
on 02025-06-17