The lock miter is an interlocking edge-to-edge joint, typically used at the corners of casework. Used in a table-mounted router, run at reduced speed, this bit cuts both halves of the joint. The same setup of bit & fence cuts both parts. One part is laid flat on the tabletop & fed across the cutter. The second is braced vertically against the fence and fed across the cutter. For best results use in a table-mounted router.