Drill without damage
1. Start with the right bit
Do-it-all twist bits are inexpensive and designed to punch through wood, metal, and plastics. To achieve this versatility, manufacturers typically grind their cutting tips to 118°. This shallow angle can allow the bit to wander on entry and blow out wood fibers on exit, so reserve twist bits for plastic, metal, and holes smaller than 1/8" in wood where the small size minimizes those tendencies.
For holes sized from 1/8" to 1/2", instead select a brad-point bit. The center point of a brad-point bit prevents wandering on entry, while the sharp outer spurs shear the wood for far less tear-out.
When you need to drill holes larger than 1/2", move up to a Forstner bit. Like brad-point bits, Forstners feature a center guiding point and cut very clean holes. Multispur Forstner bits, like the one shown right, add sawlike teeth to the rims, which cut more aggressively without sacrificing cut quality. When using this type of Forstner, slow the feed rate, and secure the workpiece with clamps.
2. Back up your cut
Regardless of bit choice, any time you punch metal through wood, unsupported wood fibers on the back of the workpiece can tear out. So get in the practice of backing up your workpiece with scrap wood. The backing board traps the wood fibers around the exit point, preventing the bit from pushing out the last splinters. At the drill press, simply slip a scrap beneath the workpiece; for handheld drilling, clamp the backer in place, as shown right. If your bits lift fibers around the entry points, apply masking tape to the face of the workpiece before marking your layout lines and drilling.
3. Drill from both directions
If the location of a hole makes it difficult to clamp a backer board in place (such as when drilling cord-access holes in the back of an entertainment center), instead drill from both directions, as shown right, for a hole with clean edges.
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