Three-dimensional printer components

A device for directional traversal in an environment contaminated by debris of three-dimensional printing, the device comprising:

• a flexible coupler configured to couple wheels including a first wheel and a second wheel, the flexible coupler configured to facilitate travel of the wheels along a long axis of a railing that is imperfect and/or is contaminated by the debris, the wheels being (i) coupled to a carriage by the flexible coupler and (ii) configured to engage with the railing along which the wheels are configured to directionally traverse, the flexible coupler is configured to facilitate bearing loads that are even or substantially even, the bearing loads being on the wheels as they travel along the railing, the device being comprised in, or being operatively coupled to, a three-dimensional printer.