Drill America DWRRTSSP Series Taper Shank, Spiral Flute Chucking Reamers Chucking Reamers are designed for accurate reaming in most materials using all types of equipment including screw machines, turret lathes, drill presses, and machining centers. They are regularly pointed with a 45º chamfer. The straight-flute design is recommended for most general purpose reaming. The right-hand spiral-flute reamer has the smooth, chatter-free action necessary for fine finishes. It is recommended over the straight-flute for more difficult materials, better surface requirements, and applications with an interruption such as a keyway or cross hole.