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.

Oversized Fractional—Oversized reamers are larger than the fraction by 0.001" in diameter to create a looser fit than standard sizes. They're typically used in holes where objects such as pins need to stay in place, but still can be easily removed.

Undersized Fractional—Undersized reamers are smaller than the fraction by 0.001" in diameter to create a tighter fit than standard sizes. They're typically used to press-fit a pin, bearing, or other object into a hole.

Cobalt Steel—With better heat and wear resistance than high-speed steel, these reamers run up to 25% faster, last longer, and perform better on hard materials, such as cast iron, hardened steel, titanium, and stainless steel.

Right-Hand Spiral—These reamers pull chips upward as they cut, so they're often used in blind holes.