REAMING; EXCESSIVE REAMER WEAR OR BREAKAGE:
The following is a list of items to consider that may adversely affect reamer life or in some cases, damage the reamer.

Misalignment creates a bell mouth condition and premature wear.
Lack of chip space in the flutes.
Inconsistent material condition.
Dirt or burs in the holding collets or spindle.
Over or underfeeding/speeding.
Lack of proper lubrication.
Bottoming out in blind holes.
Leaving too little/too much stock to remove.
Poor hole quality.
Improper regrinding.
Careless handling of the reamer.
Reamer chatter.
Lack of rigidity of the set-up.
Wrong reamer design for the application.