Which of the following tools is primarily used for filing or shaping solid materials?

The triangular file is primarily used for filing or shaping solid materials due to its specific design. Its triangular cross-section allows it to create sharp edges and precise angles when working on various materials such as wood, metal, or plastic. This tool is particularly effective for shaping corners and creating grooves, making it essential in detailed work.

In contrast, an eyewash station is a safety device used for rinsing the eyes in case of exposure to harmful substances, and it does not have a purpose related to shaping materials. A cork borer is designed for cutting circular holes in materials like cork or rubber but does not serve the general purpose of filing. A graduated cylinder is used for measuring liquid volumes and is not related to shaping solid materials at all. Thus, the triangular file stands out as the correct tool for the task described.