Synchrotron X-ray-enhanced scanning tunnelling microscopy (SXSTM) is a novel technique by which materials can be studied with elemental-sensitive and nanometre-spatial resolution. This poster covers the mechanical engineering design for the prototype SXSTM instrument. System performance and sample handling requirements along with the desire to use existing components constrained the design. The SXSTM needs to be mechanically and acoustically isolated from the environment. In addition, all sample preparations are done in situ, and thus, the sample and SXSTM tips need to be prepared and moved inside the vacuum chamber with a wobble stick. The final design incorporates an Advanced Photon Source-designed vacuum chamber, existing components and commercial parts to provide the user with a robust prototype system to demonstrate the impact of this new technique.