For finishing a blind hole by hand or machine reaming, which reamer flute style is preferred to control chip evacuation and protect the finished surface?

Introduction / Context:
Reamer flute geometry governs chip flow. In blind holes, chips must be directed back toward the shank to avoid packing at the bottom, which would score the surface or prevent reaching size. The question focuses on choosing the correct spiral direction.

Given Data / Assumptions:

• Blind hole (bottom present); finishing to size by reaming.
• Requirement: clean evacuation away from the bottom.
• Standard right- or left-hand spiral flutes available.

Concept / Approach:
Right hand spiral flutes tend to lift chips back toward the shank when the tool rotates in the conventional right-hand direction, making them suitable for blind holes. Left hand spiral reamers drive chips forward and are more suitable for through holes. Straight flutes give neutral chip flow and may pack chips in blind holes.

Step-by-Step Solution:

Verification / Alternative check:
Tool vendor catalogs explicitly recommend right hand spiral for blind holes and left hand spiral for through holes to manage chip flow safely.

Why Other Options Are Wrong:

• Straight flute: poor chip lifting; risk of scoring and jam.
• Left hand spiral: pushes chips downward; bad for blind holes.
• “Any one of these” is unsafe; choice is application-specific.

Common Pitfalls:
Confusing drill flute direction rules with reamer recommendations; always verify chip direction relative to rotation and flute hand.

Final Answer:
right hand spiral fluted reamer