Home › Blog › Buying Guide › From Factory Floor to Your Workshop: Evaluating a Pre-Owned , Used , Secondhand, Surplus CNC Machines Before Purchase Mitsui-Seiki 4DNII – CNC JIG Coordinated Hole Grinding made in Japan Here is a structured guide for evaluating a pre-owned / used / surplus Mitsui-Seiki “4DNII” CNC jig / hole grinding / coordinated hole grinding machine (or similarly classed 4DN / 4-axis jig /hole grinder), from factory floor to workshop....