The straight-flute design is recommended for most general purpose reaming.
9/32" HSS Straight Shank Spiral Flute Chucking Reamer 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. They are regularly pointed with a 45ยบ chamfer. The right-hand spiral-flute reamer has the smooth, chatter-free action necessary for fine finishes.