- Achieve superior precision, speed, and quality on your CNC machine with the 90° Amana Tool RC-1142 Decorative Insert V-Groove Router Bit (1/4″ Shank). Specifically designed for machining v-groove designs, these router bits ensure clean, accurate cuts while maximizing efficiency. Perfect for adding decorative touches 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.