Straight and spiral carbide bits for cutting grooves, dados, rabbets and pockets rather than profiles. Double-flute straight bits clear chips sideways and are the general-purpose choice; up spirals pull chips out of the cut, down spirals push them down so the top face does not tear out, and O-flute geometry is for plastics and soft material where chips weld to the cutter. Cutting diameters run 1/8 in. to 1/2 in. in 2 to 4 in. overall lengths, with chipbreaker and compression versions for sheet goods.
