Linear actuators without shafting
A major obstacle standing in the way of total self-replication by rapid prototyping machines, notably RepRap, is that certain of the components, particularly ground shafting (or threaded rod) for the Cartesian robot’s linear actuators, require greater precision than the machines are currently capable of. Thingiverse user fdavies is engaged in a noble effort to design printable linear actuators that require no shafting and are instead based on the hinged Sarrus linkage (Wikipedia). Excelsior!
