Tools of the trade. The tool investment is not huge and many of these things you may have already. Hearing and eye protection tops the list. You will need lights to shine into ports. A high-speed die grinder (air or electric) and an assortment of long-shaft carbide cutters. Sharp ones... they wear out. A bunch of 80-120 grit carbide rolls for the final smoothing, with the arbors to carry them. One of the more important tools is the digital internal caliper—a Fowler is shown—used to make sure you get the ports dimensionally correct and even with each other.