Two flute straight cutters produce a cleaner finish than the single flute cutters & are suitable for grooving rebating mortising & drilling. Use Tungsten Carbide tooling when working with abrasive materials such as chipboard MDF plywood & certain hardwoods. Two flutes give a clean finish to cut edges. 1/4 in. Shank. C = 11 mm. D = 4.0 mm. 5/32.