This research aims to build a preliminary magnetic abrasive polishing machine to polish various mold materials such as stainless steel, electroless nickel and OFCu. Ferromagnetic particles (Fe3O4) are homogeneously mixed with fine abrasive particles (Al2O3 or SiC) in this study to work as magnetic abrasive. The main polishing action is done by those abrasive particles trapped inside the ferromagnetic particles brush shaped by rotating electromagnet pole (magnetic field). Effort has been made to investigate the effect of abrasive particle size, ferromagnetic particles size, and gap between the workpiece and electromagnet pole on the achievable surface roughness. The results show that gap distance has very profound effect on the attainable surface roughness. Surface roughness (Ra) of 18 nm, 27 nm,16 nm and 29 nm are achieved on copper, OFCu, electroless nickel and stainless steel(H13) specimens respectively.