Dimar's Carbide Tipped Canoe Bits may be known as Flute & Bead bits, the Canoe bits are perfectly matched to join two pieces of wood by means of Ball & Socket.
The bits may be used to create circular planters and Strip-built canoes. Canoe makers use these bits to make long, seamless joints in the curving hulls of their canoes. Use one bit for the cove, and then the matching bit to cut the mating bead. The resulting interlocking joint has a hinging action that is perfect for any curved element. The bits may be used in hardwood, softwood, and plywood, on portable and stationary routers.
The multi-bit is made of exact matching profiles on the same bit. That ensures perfect join even after several sharpening. The Two Bits Set is a less expensive version, but it may require switching bits often.