Enlarging Existing Holes

Often, we become aware of avoidable injuries suffered from the improper use of cutting tools. One very common injury occurs from attempting to enlarge an existing hole with either one or successively larger drill bits to achieve the desired hole size. This injury is most common when using a portable electric, air, or cordless drill. The problem occurs when a 2-fluted drill grabs and wedges itself in the existing hole and the torque of the drill pulls it out of the user's closed hand. As the drill body continues to rotate at very high RPMs, it normally strikes the user on the hand and broken bones are the usual result. This happens very quickly and is very violent. Occasionally, if the power tool is large, like a 1/2” or 3/4” chuck capacity, an arm or leg bone can be easily broken.

The solution? Use the right tool for the job! Never attempt to enlarge an existing hole with a drill bit. To enlarge an existing hole, use only: a) a countersink in very thin gauge material; b) a core drill for enlarging to 60% of the hole diameter; or c) a reamer for very slight and precise hole enlarging.