I saw
this tool, an adjustable wrench that uses a fluid/valve system to adjust and lock in place.
It got me thinking about using a fluid to transmit force from a motor to the carriage. the motor, mounted to the printer frame, would be attached to a peristaltic pump. The hobbed bolt on the carriage would have a similar pump, with a loop of tubing connecting the two. in a perfect system, when the motor turns, the hobbed bolt should mimic it's movements. it would act just like a belt.
liquids are messy, but it might be an interesting area to explore.
