Specimen stability during metallographic polishing is critical to obtaining accurate microstructural observations, yet inconsistent pressure in single disc polishing machines often causes non-uniform surface finish and unreliable results. While previous studies have extensively addressed polishing parameters and machine performance, limited attention has been given to auxiliary fixtures that actively maintain specimen stability and pressure consistency, a gap this study addresses. This paper proposes a novel jig holder design that integrates finite element-based structural verification with experimental validation, offering a more consistent alternative to conventional manual polishing. The design methodology comprised requirement analysis, three-dimensional CAD modeling, structural simulation via finite element analysis (FEA) to evaluate von Mises stress, displacement, and factor of safety (FOS), followed by fabrication and experimental testing on Aluminum 6061 specimens under polishing loads of 50 g and 150 g, with manual polishing as a baseline. FEA results confirmed the structural safety of the jig holder, with a maximum von Mises stress of 0.103 MPa and a minimum factor of safety of 10. Experimentally, the jig holder consistently produced lower and more uniform surface roughness (0.220–0.225 μm) than manual polishing (0.235 μm), indicating that consistent, controlled pressure distribution rather than operator dependent manual force is the primary mechanism improving surface quality. These findings demonstrate that the proposed jig holder offers a practical, low cost solution for improving specimen preparation reliability in metallographic laboratories, with potential application in quality sensitive materials characterization workflows.