The PORTER-CABLE 43671PC Bearing Guided Dado Router Bit is designed for mortising of doors to accept hinge butts - use with No.59370 for 3", 3-1/2", and 4" hinges. This bit features ball bearing pilot for smooth cuts and even feed rates without chatter; for trimming high-pressure plastic laminate or Corian flush with substrate; trimming high-pressure plastic laminate countertop edges where a bevel is required.