This paper explores Downloadable Assistive Technologies (DAT) and the possibilities as well as the limitations of publishing and fabricating DAT through online 3D printing communities. A design probe was used for this research within the context of Thingiverse, in the form of a 3D printed dog wheelchair design probe – the FiGO Dog Wheelchair. FiGO enabled an exploration of co-customization of tools and processes for DAT, issues of design and communication around modification and personalisation, with several other themes emerging from the research. It is concluded that implementing communication guidelines for publishing DAT on Thingiverse by involving both end users as well as health professionals in the research process is vital to the process of co-fabrication and modification in an open design context.