- Achieve superior precision, speed, and quality when cutting plastic on your cnc machine with the 3mm Amana Tool 51491 Metric Plastic Spiral End Router Bit (3mm Shank). Specifically designed for machining plastic materials, these router bits ensure clean, accurate cuts while maximising efficiency. Perfect for carving and shaping plastic with ease and reliability Amana Tool Amana Tool’s cnc machine router bits are crafted from premium sub-micron grain carbide, ensuring exceptional durability and precision. Utilising an advanced edge processing system, each router bit is finished with a mirror-like polish and a razor-sharp cutting edge. This meticulous process results in clean, precise cuts, minimal chip re-welding, an outstanding surface finish, and. most importantly. an extended tool life.