Reamers wear out faster when which condition exists?

• A. Not enough stock left for reaming
• B. Excess stock left for reaming
• C. Reaming at high speed
• D. Using coated reamers

Answer: (A)

Reaming needs enough material to cut along the full length of the tool’s flutes. When there isn’t enough stock left in the bore, the reamer can’t engage the material for its entire cutting length and ends up rubbing against the bore near the exit. This rubbing generates extra heat, accelerates dulling of the cutting edges, and speeds up tool wear.

The other factors affect wear in different ways: going at a high speed increases heat and wear, coatings can reduce wear, and having more stock to cut doesn’t force the tool to rub the exit and is not the primary cause of rapid wear in this scenario.