As Primus tells us: “Jerry was a race car driver.” Jeri Ellsworth was both a race car driver and a race car designer. In this segment from a Fat Man & Circuit Girl episode, she talks about the concept behind Watt’s linkages she used in a rear suspension system she designed and how this mechanical linkage could be used in rapid prototyping/CNC machines to achieve precision positioning using much less expensive parts.
The linkage model she has in the video might be hard to understand. This animation on Wikipedia might make it easier.
BTW: I finally got to meet my new idol at Maker Faire, but alas, I did not get to hear her talk or to see her booth where she had her Easy Bake Chip Fab set up. I was there to see her present her “homebaked” solar cells to JÃ©rÃ´me Demers, Solarbotics’ intern (and MAKE Contributor), for him to build them into a BEAMbot. Can’t wait to see what he does with them.