Low Helix, Upcut, Rougher, Spiral Router Bits - (3 Flute) Solid Carbide - Vortex 5250. Cutting Edge Diameter 1/2 Cutting Edge Length 1 /14 Shank Diameter 1/2 Overall Length 3 1/2. The two and three flute roughing tools are designed for high feed rates on CNC routers and are used when surface finish is not important in dense materials such as hardwoods, particle board and plywood. These tools are very successful in CNC applications where the roughing bit makes the first cut, followed by a second cut using a profile type tool. This tool will produce a rippled edge cut and is extremely quiet and smooth cutting, even in heavy cuts and high feed rates.