Damanik, M.A. et al. 2026. Effect of Cutting Speed on Surface Roughness in Stepped Turning of ST37 Mild Steel Using HSS Cutting Tools: A Six Sigma DMAIC Approach. Inspire Global Insight Journal. 1, 03 (Jul. 2026), 83–87. DOI:https://doi.org/10.53905/igim.v1i03.16.