To reduce chatter during reaming, reamers are designed with flutes cut in which pattern?

• A. Flutes cut on a spiral or helix
• B. Straight flutes
• C. Flutes cut at a right angle
• D. Random flute angles

Answer: (A)

Chatter during reaming comes from uneven cutting forces and vibrations as the tool engages the workpiece. Designing the flutes in a spiral or helix pattern makes the cutting edges engage gradually as the tool rotates, so the load is distributed around the circumference and along the flute length. This smooths the cutting action, helps carry chips out of the hole, and keeps the tool better centered, all of which reduce vibration and produce a steadier, more accurate hole finish. Straight flutes tend to bite more abruptly and don’t evacuate chips as efficiently, which can increase chatter. Flutes cut at a right angle or in random orientations would create inconsistent engagement and poorer chip removal, making chatter worse rather than better.