Straight Flute—The most common flute style, these reamers are suitable for a wide range of applications, but not recommended for holes with a keyway or other breaks in the surface.

Spiral Flute—Since these reamers clear chips better than straight flutes, they leave holes with a smoother finish. They're better for holes with breaks in the surface, such as a keyway, because they cut continuously across the breaks instead of moving in and out.

High-Speed Steel—Durable and wear resistant, these are good for general purpose reaming in most materials.

Left-Hand Spiral—These reamers push chips downward as they cut, so they're often used in through holes.