The bored hole quality is directly affected by the cutting vibrations in a boring operation. The aim of this study is to determine an optimum condition for the conicity of the bored hole (COBH) and deviation from circularity of the bored hole (DFC) by using the experimental design method. In this study, the effects of cutting parameters and boring tool material in relation to the overhang ratio of boring tool on both of the COBH and DFC quality criteria were examined experimentally. The optimal combination of test factors was determined by using the analysis of the signal to noise (S/N) ratio. Both the lower depth of cut values and the higher effective tool length lead to deterioration in the hole quality for both criteria. Besides, an increase in the depth of cut values as well as decreasing in the feed rate lead to quality improvement with regard to the COBH and DFC quality criteria.