A lightweight cutting tool, such as a reamer, includes a front cutting body, a front cutting ring, a center tube, a rear cutting ring and a rear machine connection member. An arm assembly of the front and rear cutting heads includes one or more leading arms, one or more trailing arms and a cutting head supported by the leading and trailing arms. The leading arms and the trailing arms curve in opposite directions. To reduce weight and moment of inertia of the reamer, a cross-sectional area of the leading arms and the trailing arms is largest proximate the sleeve member and is smallest proximate the cutting head. In addition, the front cutting body, the front and rear cutting rings and the center tube may be made by additive manufacturing. Fluid can be transported entirely through the reamer to the cutting insert/workpiece interface and the guide pad/workpiece interface.